Stamford, Connecticut

Stamford, Connecticut41.0534, -73.5387

Mowing

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

Current conditions · 2pm, this hour

Prime time>95% chance

Grass
dry
Ground
firm
Rain
0% chance
Temp
18°
Wind
19 km/h

Forecast for this hour, not a measurement.

Best weekend slot

Saturday 8am–6pm

Verdict: Prime time, >95% chance at its best hour

temperature — 11°C

Next mow

Now until 7pm

Verdict: Prime time, >95% chance at its best hour

no rain since Saturday, ground firm

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. Tuesday 20 October: 5 hours worth using. Now until 7pm — no rain since Saturday, ground firm
    Tuesday 20 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance—————————>95%>95%>95%>95%>95%——
    VerdictAlready goneAlready goneAlready goneAlready goneAlready goneAlready goneAlready goneAlready goneAlready gonePrime timePrime timePrime timePrime timePrime timedarkdark
    Rainchance·········0%0%0%0%0%0%0%
    Rainmm·········———————
    Grass·········drydrydrydrydrydrydry
    Ground·········firmfirmfirmfirmfirmfirmfirm
    Temp·········18°18°17°16°14°12°11°
    Windkm/h·········191816129910
    Daylight·········✓✓✓✓✓——

    Growth: growing slowly (growth potential 0.23). 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.

    Tuesday 20 October · now until 7pmConfident

    Now until 7pm — no rain since Saturday, ground firm

    >95% prime time at its best hour, >95% that all 5 hours stay mowable. Every forecast run agrees.

    Limiting factor:none

  2. Wednesday 21 October: 11 hours worth using. 8am–7pm — temperature — 11°C

    Loading the hour-by-hour forecast…

    Growth: barely growing (growth potential 0.13). 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.

    Wednesday 21 October · 8am–7pmConfident

    8am–7pm — temperature — 11°C

    >95% prime time at its best hour, >95% that all 11 hours stay mowable. Every forecast run agrees.

    Limiting factor:temperature

  3. Thursday 22 October: 11 hours worth using. 8am–7pm — temperature — 12°C

    Loading the hour-by-hour forecast…

    Growth: barely growing (growth potential 0.15). 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.

    Thursday 22 October · 8am–7pmConfident

    8am–7pm — temperature — 12°C

    >95% prime time at its best hour, >95% that all 11 hours stay mowable. Every forecast run agrees.

    Limiting factor:temperature

  4. Friday 23 October: 11 hours worth using. 8am–7pm — temperature — 10°C

    Loading the hour-by-hour forecast…

    Growth: barely growing (growth potential 0.18). 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.

    Friday 23 October · 8am–7pmConfident

    8am–7pm — temperature — 10°C

    >95% prime time at its best hour, >95% that all 11 hours stay mowable. Every forecast run agrees.

    Limiting factor:temperature

  5. Saturday 24 October: 10 hours worth using. 8am–6pm — temperature — 11°C

    Loading the hour-by-hour forecast…

    Growth: barely growing (growth potential 0.15). 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.

    Saturday 24 October · 8am–6pmReasonably confident

    8am–6pm — temperature — 11°C

    >95% prime time at its best hour, >95% that all 10 hours stay mowable. Every forecast run agrees.

    Limiting factor:temperature

  6. Sunday 25 October: 10 hours worth using. 8am–6pm — temperature — 10°C

    Loading the hour-by-hour forecast…

    Growth: growing slowly (growth potential 0.28). 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.

    Sunday 25 October · 8am–6pmReasonably confident

    8am–6pm — temperature — 10°C

    >95% prime time at its best hour, >95% that all 10 hours stay mowable. Every forecast run agrees.

    Limiting factor:temperature

  7. Monday 26 October: 10 hours worth using. 8am–6pm — dry for over a week by then, ground firm

    Loading the hour-by-hour forecast…

    Growth: growing steadily (growth potential 0.45). 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.

    Monday 26 October · 8am–6pmReasonably confident

    8am–6pm — dry for over a week by then, ground firm

    >95% prime time at its best hour, >95% that all 10 hours stay mowable. Every forecast run agrees.

    Limiting factor:none

  8. Tuesday 27 October: 10 hours worth using. 8am–6pm — dry for over a week by then, ground firm

    Loading the hour-by-hour forecast…

    Growth: growing well (growth potential 0.51). 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.

    Tuesday 27 October · 8am–6pmReasonably confident

    8am–6pm — dry for over a week by then, ground firm

    >95% prime time at its best hour, 95% that all 10 hours stay mowable. Every forecast run agrees.

    Limiting factor:none

  9. Wednesday 28 October: 10 hours worth using. 8am–6pm — rain earlier that day, ground firm

    Loading the hour-by-hour forecast…

    Growth: growing slowly (growth potential 0.23). 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.

    Wednesday 28 October · 8am–6pmLow confidence this far out

    8am–6pm — rain earlier that day, ground firm

    >95% prime time at its best hour, 90% that all 10 hours stay mowable. Every forecast run agrees.

    Limiting factor:none

  10. Thursday 29 October: 10 hours worth using. 8am–6pm — grass damp — dry again 3 hours after a shower

    Loading the hour-by-hour forecast…

    Growth: growing slowly (growth potential 0.27). 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.

    Thursday 29 October · 8am–6pmLow confidence this far out

    8am–6pm — grass damp — dry again 3 hours after a shower

    >95% prime time at its best hour, 90% that all 10 hours stay mowable. Every forecast run agrees.

    Limiting factor:grass wetness

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

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 under it in each day's table 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 hit.

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.

23%Growing slowly

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

Growing slowly — roughly 0.8mm a day. It will not put on enough to need cutting within the next 10 days.

Held back by both temperature and short days — 10.9 hours of daylight at 12°C.

Over the next 10 days
about 9mm 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 Stamford, Connecticut

61°F16.0°C

at 6cm — germination depth

Too cold to seed — 16.0°C at 6cm, and it doesn't reach 12.5°C within the next 10 days.

Holding steady over the next 10 days.

Cross-checks against an independent estimate from air temperature (11.1°C), which agrees to within 0.8°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

Stamford, Connecticut in detail

Soil temperature in Stamford, Connecticut is currently 16.0°C at 6cm, and barely moving. 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 — 16.0°C at 6cm, and it doesn't reach 12.5°C within the next 10 days.

9 of the next 10 days are good mowing days. The other one is held back by wet grass or soft ground. The best weekend slot right now is Saturday 8am–6pm, on the basis that temperature — 11°C.

The next recommended window in Stamford opens at 2pm on Tuesday 20 October, and holds while conditions stay put. Underfoot, the ground reads as firm after 0mm rain over the last week, coarse (sandy) soil.

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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.