Rapid City, South Dakota
Best weekend slot
Monday 10am–8pm
Verdict: Good
rain earlier today, ground firm
Next mow
Today 7pm–8pm
Verdict: Good
rain earlier today, ground firm
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 23.0°C cooling to 0.0°C
Tuesday 1 September: Good. 7pm–8pm — rain earlier today, ground firm
Tuesday 1 September · 7pm–8pmConfident
7pm–8pm — rain earlier today, ground firm
- Good:Grass wetness
- Grass dryrain earlier today
- Good:Ground firmness
- Ground firm0mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 1.00
- Good:Temperature
- Cool24°C
- Good:Wind
- Wind light9 km/h
- Sociable hours
- A bit early or late, but fine
Limiting factor:none
Wednesday 2 September: Good. 8am–midday — rain earlier today, ground firm
Wednesday 2 September · 8am–middayConfident
8am–midday — rain earlier today, ground firm
- Good:Grass wetness
- Grass dryrain earlier today
- Good:Ground firmness
- Ground firm1mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.88
- Poor:Temperature
- Temperature16°C
- Good:Wind
- Wind light5 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:none
Thursday 3 September: Good. 8am–10am — growing slowly — growth potential 0.35
Thursday 3 September · 8am–10amConfident
8am–10am — growing slowly — growth potential 0.35
- Good:Grass wetness
- Grass dryno rain since Tuesday
- Good:Ground firmness
- Ground firm1mm rain over the last week
- Marginal:Growth
- Growing slowlygrowth potential 0.35
- Poor:Temperature
- Temperature20°C
- Good:Wind
- Wind light13 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:growth
Friday 4 September: Good. 8am–9am — growing slowly — growth potential 0.28
Friday 4 September · 8am–9amConfident
8am–9am — growing slowly — growth potential 0.28
- Good:Grass wetness
- Grass dryno rain since Tuesday
- Good:Ground firmness
- Ground firm1mm rain over the last week
- Marginal:Growth
- Growing slowlygrowth potential 0.28
- Poor:Temperature
- Temperature23°C
- Good:Wind
- Wind light11 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:growth
Saturday 5 September: Good. 8am–9am — growing slowly — growth potential 0.20
Saturday 5 September · 8am–9amReasonably confident
8am–9am — growing slowly — growth potential 0.20
- Good:Grass wetness
- Grass drydried off since a shower 2 hours ago
- Good:Ground firmness
- Ground firm1mm rain over the last week
- Poor:Growth
- Growing slowlygrowth potential 0.20
- Poor:Temperature
- Cool24°C
- Good:Wind
- Wind light12 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:growth
Sunday 6 September: Good. 10am–11am — heat stress — 27°C
Sunday 6 September · 10am–11amReasonably confident
10am–11am — heat stress — 27°C
- Good:Grass wetness
- Grass dryno rain since Saturday
- Good:Ground firmness
- Ground firm2mm rain over the last week
- Good:Growth
- Growing steadilygrowth potential 0.43
- Poor:Temperature
- Temperature23°C
- Good:Wind
- Wind light7 km/h
- Sociable hours
- Fine by the neighboursstarts when it stops being antisocial
Limiting factor:temperature
Monday 7 September: Good. 10am–8pm — rain earlier today, ground firm
Monday 7 September · 10am–8pmReasonably confident
10am–8pm — rain earlier today, ground firm
- Good:Grass wetness
- Grass drydried off since a shower 4 hours ago
- Good:Ground firmness
- Ground firm2mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.93
- Good:Temperature
- Temperature19°C
- Good:Wind
- Wind light11 km/h
- Sociable hours
- Fine by the neighboursstarts when it stops being antisocial
Limiting factor:none
Tuesday 8 September: Good. 9am–11am — cool — 26°C
Tuesday 8 September · 9am–11amReasonably confident
9am–11am — cool — 26°C
- Good:Grass wetness
- Grass dryrain earlier today
- Good:Ground firmness
- Ground firm4mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.73
- Marginal:Temperature
- Temperature21°C
- Good:Wind
- Wind light17 km/h
- Sociable hours
- A bit early or late, but finestarts once the dew has burnt off
Limiting factor:temperature
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 Tuesday
- Good:Ground firmness
- Ground firm6mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.98
- Good:Temperature
- Temperature17°C
- Good:Wind
- Wind light13 km/h
Limiting factor:none
Thursday 10 September: Not worth it. No — ground frozen.
Thursday 10 SeptemberLow confidence this far out
No — ground frozen.
- Good:Grass wetness
- Grass dryno rain since Tuesday
- Good:Ground firmness
- Ground firm6mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.83
- Good:Temperature
- Temperature14°C
- Good:Wind
- Wind light10 km/h
Limiting factor:none
Soil temperature
73°F23.0°C
at 6cm — germination depth
Cooling over the next 11 days.
Seeding conditions are open — soil is 23.0°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 23.0°C at 6cm and holding above 12.5°C.
Warning: Heat stress
Wednesday 2 September gets hot enough to stress the sward. Mow early or late, and raise the height.
Forecast from Open-Meteo, refreshed hourly. Soil temperature is modelled, not measured — how that works and where the thresholds come from.