Oshawa, Ontario
Best weekend slot
Sunday 10am–8pm
Verdict: Good
ground soft — 101mm rain over the last week
Next mow
Thursday midday–8pm
Verdict: Good
ground soft — 101mm rain over the last week
The next 10 days
Column height is how mowable the day is; the lighter band is the best stretch within it. The line is soil temperature at 6cm. It crosses the seeding threshold inside this forecast.
12.5°C — seeding
Soil at 6cm 21.6°C cooling to 0.0°C
Tuesday 1 September: Not worth it. No — grass wet, dew forming, rain earlier today.
Tuesday 1 SeptemberConfident
No — grass wet, dew forming, rain earlier today.
- Poor:Grass wetness
- Grass wetdew forming, rain earlier today
- Marginal:Ground firmness
- Ground soft in places45mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.99
- Good:Temperature
- Temperature20°C
- Good:Wind
- Wind light7 km/h
Limiting factor:grass wetness
Wednesday 2 September: Not worth it. No — 40.0mm of rain falling.
Wednesday 2 SeptemberConfident
No — 40.0mm of rain falling.
- Poor:Grass wetness
- Grass wetno rain since Monday
- Poor:Ground firmness
- Ground soft46mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.99
- Good:Temperature
- Temperature20°C
- Good:Wind
- Wind light14 km/h
Limiting factor:grass wetness
Thursday 3 September: Good. midday–8pm — ground soft — 101mm rain over the last week
Thursday 3 September · midday–8pmConfident
midday–8pm — ground soft — 101mm rain over the last week
- Marginal:Grass wetness
- Grass dryrain earlier today
- Poor:Ground firmness
- Ground soft101mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.96
- Good:Temperature
- Temperature17°C
- Good:Wind
- Wind light6 km/h
- Sociable hours
- Fine by the neighboursstarts once the dew has burnt off
Limiting factor:ground firmness
Friday 4 September: Good. 8am–8pm — ground soft — 101mm rain over the last week
Friday 4 September · 8am–8pmConfident
8am–8pm — ground soft — 101mm rain over the last week
- Good:Grass wetness
- Grass dryno rain since Wednesday
- Poor:Ground firmness
- Ground soft101mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.99
- Good:Temperature
- Temperature16°C
- Good:Wind
- Wind light10 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:ground firmness
Saturday 5 September: Good. 8am–8pm — ground soft — 101mm rain over the last week
Saturday 5 September · 8am–8pmReasonably confident
8am–8pm — ground soft — 101mm rain over the last week
- Good:Grass wetness
- Grass dryno rain since Wednesday
- Poor:Ground firmness
- Ground soft101mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.94
- Good:Temperature
- Temperature14°C
- Good:Wind
- Wind light14 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:ground firmness
Sunday 6 September: Good. 10am–8pm — ground soft — 101mm rain over the last week
Sunday 6 September · 10am–8pmReasonably confident
10am–8pm — ground soft — 101mm rain over the last week
- Good:Grass wetness
- Grass dryno rain since Wednesday
- Poor:Ground firmness
- Ground soft101mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.89
- Good:Temperature
- Temperature14°C
- Good:Wind
- Wind light8 km/h
- Sociable hours
- Fine by the neighboursstarts when it stops being antisocial
Limiting factor:ground firmness
Monday 7 September: Good. 8am–8pm — ground soft in places — 100mm rain over the last week
Monday 7 September · 8am–8pmReasonably confident
8am–8pm — ground soft in places — 100mm rain over the last week
- Good:Grass wetness
- Grass dryno rain since Wednesday
- Marginal:Ground firmness
- Ground soft in places100mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.93
- Good:Temperature
- Temperature15°C
- Good:Wind
- Wind light7 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:ground firmness
Tuesday 8 September: Good. 8am–8pm — ground soft in places — 55mm rain over the last week
Tuesday 8 September · 8am–8pmReasonably confident
8am–8pm — ground soft in places — 55mm rain over the last week
- Good:Grass wetness
- Grass dryno rain since Wednesday
- Marginal:Ground firmness
- Ground soft in places55mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.83
- Good:Temperature
- Temperature17°C
- Good:Wind
- Wind light13 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:ground firmness
Wednesday 9 September: Not worth it. No — ground frozen.
Wednesday 9 SeptemberLow confidence this far out
No — ground frozen.
- Good:Grass wetness
- Grass dryno rain since Wednesday
- Good:Ground firmness
- Ground soft in places54mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.56
- Good:Temperature
- Temperature10°C
- Good:Wind
- Wind light13 km/h
Limiting factor:ground firmness
Thursday 10 September: Not worth it. No — ground frozen.
Thursday 10 SeptemberLow confidence this far out
No — ground frozen.
- Poor:Grass wetness
- Grass wetraining now
- Marginal:Ground firmness
- Ground soft in places0mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.78
- Good:Temperature
- Temperature15°C
- Good:Wind
- Wind light6 km/h
Limiting factor:grass wetness
Soil temperature
21.8°C71°F
at 6cm — germination depth
Cooling over the next 11 days.
Seeding conditions are open — soil is 21.8°C at 6cm and holding above 12.5°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 use12.5°C as the seeding threshold.
I know what grass I have
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 temp | Days |
|---|---|---|
| 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 |
What this means right now
Good: Seeding window open
Seeding conditions are open — soil is 21.8°C at 6cm and holding above 12.5°C.
Warning: Heat stress
Thursday 3 September gets hot enough to stress the sward. Mow early or late, and raise the height.
Worth watching: Ground still soft
46mm rain over the last week. A mower will mark it, and a ride-on will rut it.
Forecast from Open-Meteo, refreshed hourly. Soil temperature is modelled, not measured — how that works and where the thresholds come from.