Pittsburgh, Pennsylvania
Mowing
When you can next cut it, and the best slot this weekend.
Best weekend slot
Saturday 9am–7pm
Verdict: Prime time, >95% chance it holds
ground soft in places — 0mm rain over the last week, fine (clay) soil
Next mow
Thursday 3pm–7pm
Verdict: Prime time, >95% chance it holds
ground soft — 38mm rain over the last week, fine (clay) soil
- Worth watching: Ground still soft. 90mm rain over the last week, fine (clay) soil. A mower will mark it, and a ride-on will rut it. 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.
Monday 19 October: no hours worth using. No — ground saturated, 90mm rain over the last week, fine (clay) soil.
Monday 19 October, hour by hour 5am 6am 7am 8am 9am 10am 11am midday 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm Chance — — — <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% — — Verdict dark dark dark Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it dark dark Rainchance 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% Rainmm — — — — — — — — — — — — — — — — Grass soaked soaked soaked soaked soaked soaked wet dry dry dry dry dry dry dry dry dry Ground sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden Temp 4° 4° 4° 4° 6° 9° 12° 14° 15° 16° 17° 17° 16° 15° 13° 12° Windkm/h 5 5 4 1 5 2 2 4 4 3 3 5 4 3 4 5 Daylight — — — ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ — — Growth: barely growing (growth potential 0.11). 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 OctoberConfident
No — ground saturated, 90mm rain over the last week, fine (clay) soil.
<5% forget it. Almost every run found the ground too soft.
Limiting factor:ground firmness
Tuesday 20 October: no hours worth using. No — ground saturated, 90mm rain over the last week, fine (clay) soil.
Tuesday 20 October, hour by hour 5am 6am 7am 8am 9am 10am 11am midday 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm Chance — — — <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% — — Verdict dark dark dark Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it dark dark Rainchance 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% Rainmm — — — — — — — — — — — — — — — — Grass soaked soaked soaked soaked soaked soaked soaked dry dry dry dry dry dry dry dry dry Ground sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden Temp 6° 6° 6° 5° 8° 10° 13° 15° 16° 17° 18° 18° 17° 16° 14° 14° Windkm/h 6 6 6 4 4 3 5 5 6 8 10 11 8 4 5 4 Daylight — — — ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ — — Growth: barely growing (growth potential 0.19). 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 OctoberConfident
No — ground saturated, 90mm rain over the last week, fine (clay) soil.
<5% forget it. Almost every run found the ground too soft.
Limiting factor:ground firmness
Wednesday 21 October: no hours worth using. No — ground saturated, 90mm rain over the last week, fine (clay) soil.
Wednesday 21 October, hour by hour 5am 6am 7am 8am 9am 10am 11am midday 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm Chance — — — <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% — — Verdict dark dark dark Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it Forget it dark dark Rainchance 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% Rainmm — — — — — — — — — — — — — — — — Grass wet wet soaked soaked soaked damp dry dry dry dry dry dry dry dry dry dry Ground sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden sodden Temp 9° 8° 8° 8° 9° 11° 14° 16° 17° 18° 19° 19° 18° 16° 15° 14° Windkm/h 5 4 4 4 4 4 5 5 5 3 5 6 7 5 4 3 Daylight — — — ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ — — Growth: growing slowly (growth potential 0.31). 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 21 OctoberConfident
No — ground saturated, 90mm rain over the last week, fine (clay) soil.
<5% forget it. Almost every run found the ground too soft.
Limiting factor:ground firmness
Thursday 22 October: 4 hours worth using. 3pm–7pm — ground soft — 38mm rain over the last week, fine (clay) soil
Thursday 22 October, hour by hour 5am 6am 7am 8am 9am 10am 11am midday 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm Chance — — — <5% <5% <5% <5% <5% <5% <5% >95% >95% >95% >95% — — Verdict dark dark dark Forget it Forget it Forget it Forget it Forget it Forget it Forget it Prime time Prime time Prime time Prime time dark dark Rainchance 0% 0% 0% 0% 0% 0% 1% 1% 0% 1% 1% 0% 0% 0% 0% 0% Rainmm — — — — — — — — — — — — — — — — Grass wet soaked soaked soaked soaked damp dry dry dry dry dry dry dry dry dry dry Ground sodden sodden frozen sodden soggy soggy soggy soggy soggy soggy soggy soggy soggy soggy soggy soggy Temp 8° 8° 7° 7° 9° 11° 13° 15° 16° 18° 18° 18° 18° 16° 15° 14° Windkm/h 4 5 4 4 4 4 6 6 7 8 8 8 7 5 6 6 Daylight — — — ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ — — 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.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 October · 3pm–7pmConfident
3pm–7pm — ground soft — 38mm rain over the last week, fine (clay) soil
>95% prime time — the chance it holds right through, not the chance at any one hour. Every forecast run agrees.
Limiting factor:ground firmness
Friday 23 October: 11 hours worth using. 8am–7pm — ground soft in places — 38mm rain over the last week, fine (clay) soil
Friday 23 October, hour by hour 5am 6am 7am 8am 9am 10am 11am midday 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm Chance — — — >95% >95% >95% >95% >95% >95% >95% >95% >95% >95% >95% — — Verdict dark dark dark Prime time Prime time Prime time Prime time Prime time Prime time Prime time Prime time Prime time Prime time Prime time dark dark Rainchance 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% Rainmm — — — — — — — — — — — — — — — — Grass dry dry dry dry dry dry dry dry dry dry dry dry dry dry dry dry Ground soggy soggy soggy soggy soggy soggy soft soft soft soft soft soft soft soft soft soft Temp 9° 9° 9° 9° 10° 12° 14° 16° 17° 18° 18° 18° 18° 16° 15° 14° Windkm/h 4 4 4 4 5 7 7 8 8 9 9 9 10 8 7 9 Daylight — — — ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ — — Growth: growing slowly (growth potential 0.30). 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.
Friday 23 October · 8am–7pmReasonably confident
8am–7pm — ground soft in places — 38mm rain over the last week, fine (clay) soil
>95% prime time — the chance it holds right through, not the chance at any one hour. Every forecast run agrees.
Limiting factor:ground firmness
Saturday 24 October: 10 hours worth using. 9am–7pm — ground soft in places — 0mm rain over the last week, fine (clay) soil
Saturday 24 October, hour by hour 5am 6am 7am 8am 9am 10am 11am midday 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm Chance — — — <5% >95% >95% >95% >95% >95% >95% >95% >95% >95% >95% — — Verdict dark dark dark ground frozen Prime time Prime time Prime time Prime time Prime time Prime time Prime time Prime time Prime time Prime time dark dark Rainchance 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% Rainmm — — — — — — — — — — — — — — — — Grass dry dry dry dry dry dry dry dry dry dry dry dry dry dry dry dry Ground frozen frozen frozen frozen soft soft soft soft soft soft soft soft soft soft soft soft Temp 9° 8° 8° 8° 9° 11° 13° 15° 16° 17° 18° 18° 17° 16° 15° 13° Windkm/h 10 10 9 8 8 8 8 8 7 7 7 9 10 11 11 11 Daylight — — — ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ — — 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.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 October · 9am–7pmReasonably confident
9am–7pm — ground soft in places — 0mm rain over the last week, fine (clay) soil
>95% prime time — the chance it holds right through, not the chance at any one hour. Every forecast run agrees.
Limiting factor:ground firmness
Sunday 25 October: 10 hours worth using. 9am–7pm — ground firm — 0mm rain over the last week, fine (clay) soil
Sunday 25 October, hour by hour 5am 6am 7am 8am 9am 10am 11am midday 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm Chance — — — <5% >95% >95% >95% >95% >95% >95% >95% >95% >95% >95% — — Verdict dark dark dark ground frozen Prime time Prime time Prime time Prime time Prime time Prime time Prime time Prime time Prime time Prime time dark dark Rainchance 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% Rainmm — — — — — — — — — — — — — — — — Grass dry dry dry dry dry dry dry dry dry dry dry dry dry dry dry dry Ground frozen frozen frozen frozen firm firm firm firm firm firm firm firm firm firm firm firm Temp 9° 8° 8° 8° 9° 11° 13° 15° 16° 18° 18° 18° 17° 16° 15° 14° Windkm/h 5 5 4 5 6 7 8 9 9 10 9 9 8 7 7 7 Daylight — — — ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ — — 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.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 October · 9am–7pmReasonably confident
9am–7pm — ground firm — 0mm rain over the last week, fine (clay) soil
>95% prime time — the chance it holds right through, not the chance at any one hour. Every forecast run agrees.
Limiting factor:ground firmness
Monday 26 October: no hours worth using. No — ground frozen.
Monday 26 October, hour by hour 5am 6am 7am 8am 9am 10am 11am midday 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm Chance — — — <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% — — Verdict dark dark dark ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen dark dark Rainchance 3% 0% 1% 3% 0% 1% 0% 0% 3% 1% 1% 3% 0% 1% 4% 0% Rainmm — — — — — — — — — — — — — — — — Grass dry dry dry dry dry dry dry dry dry dry dry dry dry dry dry dry Ground firm frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen Temp 12° 12° 12° 12° 13° 14° 16° 17° 19° 20° 20° 20° 20° 19° 17° 16° Windkm/h 8 8 9 10 10 11 12 13 13 13 12 11 10 9 8 7 Daylight — — — ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ — — Growth: growing steadily (growth potential 0.46). 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 OctoberReasonably confident
No — ground frozen.
<5% forget it. Almost every run went against it.
Limiting factor:none
Tuesday 27 October: no hours worth using. No — ground frozen.
Tuesday 27 October, hour by hour 5am 6am 7am 8am 9am 10am 11am midday 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm Chance — — — <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% — — Verdict dark dark dark ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen dark dark Rainchance 1% 1% 0% 1% 3% 0% 5% 1% 0% 1% 1% 7% 1% 0% 4% 3% Rainmm — — — — — — — — — — — — — — — — Grass dry dry dry dry dry dry dry dry dry dry dry dry dry dry dry dry Ground frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen Temp 12° 12° 12° 12° 13° 15° 16° 18° 19° 20° 21° 20° 20° 19° 18° 16° Windkm/h 6 6 6 7 8 11 13 14 14 14 14 12 11 11 11 11 Daylight — — — ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ — — Growth: growing steadily (growth potential 0.49). 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 OctoberLow confidence this far out
No — ground frozen.
<5% forget it. Almost every run went against it.
Limiting factor:none
Wednesday 28 October: no hours worth using. No — ground frozen.
Wednesday 28 October, hour by hour 5am 6am 7am 8am 9am 10am 11am midday 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm Chance — — — <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% <5% — — Verdict dark dark dark ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen ground frozen dark Already gone Rainchance 1% 1% 1% 1% 1% 3% 1% 1% 1% 3% 4% 0% 2% 3% 0% · Rainmm — — — — — — — — — — — — — — — · Grass dry dry dry dry dry dry dry dry dry dry dry dry dry dry dry · Ground frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen frozen · Temp 13° 13° 12° 12° 11° 10° 9° 8° 8° 7° 7° 7° 7° 7° 7° · Windkm/h 6 5 8 12 14 16 16 16 15 14 12 10 9 8 9 · Daylight — — — ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ — · Growth: growing slowly (growth potential 0.20). 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 OctoberLow confidence this far out
No — ground frozen.
<5% forget it. Almost every run went against it.
Limiting factor:none
good to go touch and go dark, frost or snow already goneFainter means fewer forecast runs agree.
Growth
How fast it is growing, and when it will need cutting again.
11%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 — 11.0 hours of daylight at 9°C.
- Over the next 10 days
- about 10mm 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 Pittsburgh, Pennsylvania
44°F6.4°C
at 6cm — germination depth
Too cold to seed — 6.4°C at 6cm and not warming.
Cooling over the next 10 days.
Cross-checks against an independent estimate from air temperature (10.9°C), which agrees to within 1.1°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.
| Species | Soil needed | Days to sprout |
|---|---|---|
| Perennial ryegrass | 8°C | 5–10 |
| Red / chewings fescue | 8–10°C | 10–14 |
| Tall fescuelikely yours | 10–12°C | 10–14 |
| Browntop bentColonial bentgrass | 10–12°C | 14–21 |
| Smooth-stalked meadow grassKentucky bluegrasslikely yours | 12–13°C | 14–28 |
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.
Pittsburgh, Pennsylvania in detail
Soil temperature in Pittsburgh, Pennsylvania is currently 6.4°C at 6cm, and falling about 6.2°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 — 6.4°C at 6cm and not warming.
7 of the next 10 days are good mowing days. The best weekend slot right now is Saturday 9am–7pm, on the basis that ground soft in places — 0mm rain over the last week, fine (clay) soil.
The next recommended window in Pittsburgh opens at 3pm on Thursday 22 October, and holds while conditions stay put. Underfoot, the ground reads as saturated after 90mm rain over the last week, fine (clay) soil.
Save this lawn and we will email you when the windows open.
We already send you the forecast email? Use the same address.
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.