Ithaca, New York

Ithaca, New York42.4406, -76.4966from your postcode

Mowing

When you can next cut it, and the best slot this weekend.

Best weekend slot

Nothing doing

Verdict: Not worth it

Nothing to cut — the grass is barely growing (growth potential 0.05). Conditions themselves are fine.

Today morning is your first decent window.

Next mow

Today 9am–7pm

Verdict: Prime time, >95% chance it holds

temperature — 11°C

  • Warning: Frost about. Wednesday 21 October has frosted hours. Stay off it until it lifts — walking on frosted grass bruises it, and mowing it ruptures the leaf. More

The next 10 days

Each row is a day, morning on the left. The more solid a block, the more of the forecast runs agree you can mow. Open a day for the hour-by-hour forecast behind it.

  1. Monday 19 October: 10 hours worth using. 9am–7pm — temperature — 11°C
    Monday 19 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance———<5%>95%>95%>95%>95%>95%>95%>95%>95%>95%>95%——
    VerdictdarkdarkdarkForget itPrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timedarkdark
    Rainchance0%0%0%0%0%0%0%0%0%0%0%0%0%0%0%0%
    Rainmm————————————————
    Grassdrydrydrydrydrydrydrydrydrydrydrydrydrydrydrydry
    Groundfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirm
    Temp5°5°4°4°7°11°15°17°19°20°20°20°19°15°13°12°
    Windkm/h101078732432598888
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: barely growing (growth potential 0.16). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.Chance is the share of 82 forecast runs — the same weather models re-run from slightly different starting conditions — in which you could have mowed that hour. The rows below it are what those runs expect on average, which is why an hour can look reasonable line by line and still fall short: the chance only counts runs where everything came together at once. Hover any cell for what the runs that ruled it out actually hit.

    Monday 19 October · 9am–7pmConfident

    9am–7pm — temperature — 11°C

    >95% prime time — the chance it holds right through, not the chance at any one hour. Every forecast run agrees.

    Limiting factor:temperature

  2. Tuesday 20 October: 11 hours worth using. 8am–7pm — temperature — 11°C
    Tuesday 20 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance———>95%>95%>95%>95%>95%>95%>95%>95%>95%>95%>95%——
    VerdictdarkdarkdarkPrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timedarkdark
    Rainchance0%0%0%0%0%0%0%0%0%0%0%0%0%0%0%0%
    Rainmm————————————————
    Grassdrydrydrydrydrydrydrydrydrydrydrydrydrydrydrydry
    Groundfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirm
    Temp6°6°6°6°8°11°13°15°17°18°17°17°16°13°10°8°
    Windkm/h0632479131718171716141210
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: barely growing (growth potential 0.17). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.Chance is the share of 82 forecast runs — the same weather models re-run from slightly different starting conditions — in which you could have mowed that hour. The rows below it are what those runs expect on average, which is why an hour can look reasonable line by line and still fall short: the chance only counts runs where everything came together at once. Hover any cell for what the runs that ruled it out actually hit.

    Tuesday 20 October · 8am–7pmConfident

    8am–7pm — temperature — 11°C

    >95% prime time — the chance it holds right through, not the chance at any one hour. Every forecast run agrees.

    Limiting factor:temperature

  3. Wednesday 21 October: nothing to cut. Nothing to cut — the grass is barely growing (growth potential 0.07). Conditions themselves are fine.
    Wednesday 21 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance———<5%<5%<5%<5%>95%>95%>95%>95%>95%>95%>95%——
    Verdictnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growing
    Rainchance0%0%0%0%0%0%0%0%0%0%0%0%0%0%0%0%
    Rainmm————————————————
    Grasssoakedsoakedsoakedsoakedsoakedsoakedsoakeddrydrydrydrydrydrydrydrydry
    Groundfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirm
    Temp4°4°3°4°7°10°12°14°15°16°16°16°15°11°9°8°
    Windkm/h2111134469988876
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: barely growing (growth potential 0.07). Not enough to be worth cutting, which is why no hour is recommended today whatever the weather does.Chance is the share of 82 forecast runs — the same weather models re-run from slightly different starting conditions — in which you could have mowed that hour. The rows below it are what those runs expect on average, which is why an hour can look reasonable line by line and still fall short: the chance only counts runs where everything came together at once. Hover any cell for what the runs that ruled it out actually hit.

    Wednesday 21 OctoberConfident

    Nothing to cut — the grass is barely growing (growth potential 0.07). Conditions themselves are fine.

    >95% nothing to cut. Every forecast run agrees.

    Nothing to cut. The odds below describe the weather only — growth decides whether a cut is wanted, and it is judged separately.

    Limiting factor:growth

  4. Thursday 22 October: nothing to cut. Nothing to cut — the grass is barely growing (growth potential 0.06). Conditions themselves are fine.
    Thursday 22 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance———<5%<5%<5%>95%90%90%90%>95%>95%90%>95%——
    Verdictnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growing
    Rainchance0%0%0%0%0%2%0%9%8%9%2%4%8%3%2%4%
    Rainmm————————————————
    Grasssoakedsoakedsoakedsoakedsoakedsoakeddrydrydrydrydrydrydrydrydrydry
    Groundfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirm
    Temp3°2°3°3°6°9°11°13°15°15°16°16°15°11°9°8°
    Windkm/h656679111414161617151197
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: barely growing (growth potential 0.06). Not enough to be worth cutting, which is why no hour is recommended today whatever the weather does.Chance is the share of 82 forecast runs — the same weather models re-run from slightly different starting conditions — in which you could have mowed that hour. The rows below it are what those runs expect on average, which is why an hour can look reasonable line by line and still fall short: the chance only counts runs where everything came together at once. Hover any cell for what the runs that ruled it out actually hit.

    Thursday 22 OctoberConfident

    Nothing to cut — the grass is barely growing (growth potential 0.06). Conditions themselves are fine.

    >95% nothing to cut. Every forecast run agrees.

    Nothing to cut. The odds below describe the weather only — growth decides whether a cut is wanted, and it is judged separately.

    Limiting factor:growth

  5. Friday 23 October: nothing to cut. Nothing to cut — the grass is barely growing (growth potential 0.08). Conditions themselves are fine.
    Friday 23 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance———<5%<5%<5%95%>95%>95%>95%>95%>95%>95%>95%——
    Verdictnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growing
    Rainchance0%1%0%0%1%1%1%1%0%1%0%0%1%0%0%0%
    Rainmm————————————————
    Grasssoakedsoakedsoakedsoakedsoakedsoakeddrydrydrydrydrydrydrydrydrydry
    Groundfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirm
    Temp5°5°4°4°6°9°11°13°14°14°14°14°13°9°7°6°
    Windkm/h78888912131312131311863
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: barely growing (growth potential 0.08). Not enough to be worth cutting, which is why no hour is recommended today whatever the weather does.Chance is the share of 82 forecast runs — the same weather models re-run from slightly different starting conditions — in which you could have mowed that hour. The rows below it are what those runs expect on average, which is why an hour can look reasonable line by line and still fall short: the chance only counts runs where everything came together at once. Hover any cell for what the runs that ruled it out actually hit.

    Friday 23 OctoberReasonably confident

    Nothing to cut — the grass is barely growing (growth potential 0.08). Conditions themselves are fine.

    >95% nothing to cut. Every forecast run agrees.

    Nothing to cut. The odds below describe the weather only — growth decides whether a cut is wanted, and it is judged separately.

    Limiting factor:growth

  6. Saturday 24 October: nothing to cut. Nothing to cut — the grass is barely growing (growth potential 0.05). Conditions themselves are fine.
    Saturday 24 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance———<5%>95%>95%>95%>95%>95%>95%>95%>95%>95%>95%——
    Verdictnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growing
    Rainchance0%0%0%1%0%0%0%0%0%0%0%0%0%0%0%0%
    Rainmm————————————————
    Grassdrydrydrydrydrydrydrydrydrydrydrydrydrydrydrydry
    Groundfrozenfrozenfrozenfrozenfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirm
    Temp2°2°2°2°5°8°11°13°14°15°15°14°13°11°9°7°
    Windkm/h910101111111212131312109101111
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: barely growing (growth potential 0.05). Not enough to be worth cutting, which is why no hour is recommended today whatever the weather does.Chance is the share of 82 forecast runs — the same weather models re-run from slightly different starting conditions — in which you could have mowed that hour. The rows below it are what those runs expect on average, which is why an hour can look reasonable line by line and still fall short: the chance only counts runs where everything came together at once. Hover any cell for what the runs that ruled it out actually hit.

    Saturday 24 OctoberReasonably confident

    Nothing to cut — the grass is barely growing (growth potential 0.05). Conditions themselves are fine.

    >95% nothing to cut. Every forecast run agrees.

    Nothing to cut. The odds below describe the weather only — growth decides whether a cut is wanted, and it is judged separately.

    Limiting factor:growth

  7. Sunday 25 October: nothing to cut. Nothing to cut — the grass is barely growing (growth potential 0.07). Conditions themselves are fine.
    Sunday 25 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance———<5%>95%>95%>95%>95%>95%>95%>95%>95%>95%>95%——
    Verdictnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growingnothing to cut — the grass is barely growing
    Rainchance0%0%0%0%0%0%0%0%0%0%0%0%0%0%0%0%
    Rainmm————————————————
    Grassdrydrydrydrydrydrydrydrydrydrydrydrydrydrydrydry
    Groundfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirm
    Temp3°3°2°3°6°9°12°14°16°17°17°16°15°13°11°10°
    Windkm/h11111212131517181817171615141414
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: barely growing (growth potential 0.07). Not enough to be worth cutting, which is why no hour is recommended today whatever the weather does.Chance is the share of 82 forecast runs — the same weather models re-run from slightly different starting conditions — in which you could have mowed that hour. The rows below it are what those runs expect on average, which is why an hour can look reasonable line by line and still fall short: the chance only counts runs where everything came together at once. Hover any cell for what the runs that ruled it out actually hit.

    Sunday 25 OctoberReasonably confident

    Nothing to cut — the grass is barely growing (growth potential 0.07). Conditions themselves are fine.

    >95% nothing to cut. Every forecast run agrees.

    Nothing to cut. The odds below describe the weather only — growth decides whether a cut is wanted, and it is judged separately.

    Limiting factor:growth

  8. Monday 26 October: 11 hours worth using. 8am–7pm — grass dry — dry again 2 hours after a shower
    Monday 26 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance———90%90%90%95%>95%95%>95%>95%>95%>95%>95%——
    VerdictdarkdarkdarkPrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timedarkdark
    Rainchance0%4%1%2%3%1%1%0%5%0%3%4%3%3%1%6%
    Rainmm————0.1———————————
    Grassdrydrydrydrydrydrydrydrydrydrydrydrydrydrydrydry
    Groundfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirm
    Temp8°8°9°9°11°13°15°17°19°20°20°20°18°16°13°11°
    Windkm/h111111101011131517191917141298
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: growing slowly (growth potential 0.29). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.Chance is the share of 82 forecast runs — the same weather models re-run from slightly different starting conditions — in which you could have mowed that hour. The rows below it are what those runs expect on average, which is why an hour can look reasonable line by line and still fall short: the chance only counts runs where everything came together at once. Hover any cell for what the runs that ruled it out actually hit.

    Monday 26 October · 8am–7pmReasonably confident

    8am–7pm — grass dry — dry again 2 hours after a shower

    80% good to go — the chance it holds right through, not the chance at any one hour. About 1 run in 4 found the grass too wet.

    Limiting factor:grass wetness

  9. Tuesday 27 October: 11 hours worth using. 8am–7pm — temperature — 12°C
    Tuesday 27 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance———80%80%80%90%90%95%95%>95%95%90%>95%——
    VerdictdarkdarkdarkGood to goGood to goGood to goPrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timedarkdark
    Rainchance5%3%6%6%6%8%9%11%4%7%1%6%10%4%4%5%
    Rainmm————————————————
    Grassdampdampdrydampdampdrydrydrydrydrydrydrydrydrydrydry
    Groundfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirm
    Temp7°7°6°7°9°12°15°18°19°21°21°20°19°18°16°14°
    Windkm/h6891011121315182020201915119
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: growing slowly (growth potential 0.25). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.Chance is the share of 82 forecast runs — the same weather models re-run from slightly different starting conditions — in which you could have mowed that hour. The rows below it are what those runs expect on average, which is why an hour can look reasonable line by line and still fall short: the chance only counts runs where everything came together at once. Hover any cell for what the runs that ruled it out actually hit.

    Tuesday 27 October · 8am–7pmLow confidence this far out

    8am–7pm — temperature — 12°C

    65% good to go — the chance it holds right through, not the chance at any one hour. About 1 run in 3 hit rain.

    Limiting factor:temperature

  10. Wednesday 28 October: 11 hours worth using. 8am–7pm — grass damp — rain falling then
    Wednesday 28 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance———90%90%90%90%90%90%90%85%85%85%85%——
    VerdictdarkdarkdarkPrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timePrime timedarkAlready gone
    Rainchance2%3%3%4%4%1%6%4%1%5%4%3%1%4%0%·
    Rainmm——————0.1————————·
    Grassdrydrydrydrydrydrydrydrydrydrydrydrydrydrydry·
    Groundfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirm·
    Temp10°9°9°8°7°6°6°5°5°5°5°6°6°5°4°·
    Windkm/h141616171718181716151618191612·
    Daylight———✓✓✓✓✓✓✓✓✓✓✓—·

    Growth: barely growing (growth potential 0.10). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.Chance is the share of 82 forecast runs — the same weather models re-run from slightly different starting conditions — in which you could have mowed that hour. The rows below it are what those runs expect on average, which is why an hour can look reasonable line by line and still fall short: the chance only counts runs where everything came together at once. Hover any cell for what the runs that ruled it out actually hit.

    Wednesday 28 October · 8am–7pmLow confidence this far out

    8am–7pm — grass damp — rain falling then

    85% prime time — the chance it holds right through, not the chance at any one hour. About 1 run in 6 found the grass too wet.

    Limiting factor:grass wetness

good to go touch and go dark, frost or snow already goneFainter means fewer forecast runs agree.

How you feel about mowing

Sensible middle ground.

Petrol or battery. The baseline.

Growth

How fast it is growing, and when it will need cutting again.

16%Barely growing

Of the fastest this grass could grow. The turf-industry measure, from today's temperature and day length.

The lawn is barely growing, so it does not need cutting. Leave it — taking leaf off a sward that cannot replace it costs more than it gives.

Held back by both temperature and short days — 10.9 hours of daylight at 11°C.

Over the next 10 days
about 5mm of leaf
Next cut due
not within the next ten days

This only knows temperature and day length. Feeding, watering, shade and cutting height all move it, so treat it as a rough guide.

Worked out from the PACE Turf growth potential model and day length —how and why.

Seeding

Soil temperature at germination depth, and when the window opens.

Soil temperature in Ithaca, New York

45°F7.0°C

at 6cm — germination depth

Too cold to seed — 7.0°C at 6cm and not warming.

Cooling over the next 10 days.

Cross-checks against an independent estimate from air temperature (10.2°C), which agrees to within 0.7°C.

Most cool-season lawns in the northern US and Canada are bluegrass, tall fescue, or a mix of the two. We assume that, and use 12.5°C as the seeding threshold.

Thresholds for every species

The differences are small. Ryegrass is the quickest off the mark; bluegrass is the slowest and wants the warmest soil. Everything else sits between.

Soil temperature at 6cm for reliable germination. Sources onthe method page.
SpeciesSoil neededDays to sprout
Perennial ryegrass8°C5–10
Red / chewings fescue8–10°C10–14
Tall fescuelikely yours10–12°C10–14
Browntop bentColonial bentgrass10–12°C14–21
Smooth-stalked meadow grassKentucky bluegrasslikely yours12–13°C14–28

Feeding

Why timing decides whether a feed does anything at all.

Coming in the app

Grass takes up nitrogen when it is growing. Feed a lawn that has stopped and most of it washes past the roots — which is why timing beats product choice.

Right now this lawn is not growing fast enough to make much use of a feed.

The app will work out the actual feeding windows for your lawn — along with weed control, scarifying and moss treatment — and tell you when they open without you having to check.

Why timing beats product choice

Ithaca, New York in detail

Soil temperature in Ithaca, New York is currently 7.0°C at 6cm, and falling about 5.2°C over the next 10 days. That depth matters because it is where grass seed sits and where roots start working, and it lags air temperature by days — which is why a warm afternoon here tells you very little on its own.

Lawns in this area are typically Kentucky bluegrass with tall fescue, the usual mix for cool-season lawns at this latitude. That blend needs the soil to hold above 12.5°C before seed germinates reliably. Too cold to seed — 7.0°C at 6cm and not warming.

4 of the next 10 days look workable. As for the weekend: nothing doing. Nothing to cut — the grass is barely growing (growth potential 0.05). Conditions themselves are fine.

The next recommended window in Ithaca opens at 9am on Monday 19 October, because anything earlier is the hour your neighbours will remember. Underfoot, the ground reads as firm after 3mm rain over the last week, medium (loam) soil.

There is frost in the forecast for Ithaca, New York: Wednesday 21 October has hours cold enough to freeze the leaf. Stay off the grass until it lifts — mowing frosted turf ruptures the cells and the damage shows for weeks.

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Chances counted across 82 forecast runs from NCEP GEFS, 25km and ECMWF IFS ensemble, 25km. Forecast from Open-Meteo, refreshed through the day. Soil temperature is modelled, not measured — how that works and where the thresholds come from.