Calgary, Alberta

Best weekend slot

Sunday 10am–9pm

Verdict: Good

growing slowly — growth potential 0.27

Next mow

Today 6pm–9pm

Verdict: Good

temperature — 22°C

How you feel about mowing

Sensible middle ground.

Petrol or battery. The baseline.

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 24.0°C cooling to 0.0°C

Tuesday 1 September: Good. 6pm–9pm — temperature — 22°C

Tuesday 1 September · 6pm–9pmConfident

6pm–9pm — temperature — 22°C

Good:Grass wetness
Grass dryno rain in over a week
Good:Ground firmness
Ground firm0mm rain over the last week
Good:Growth
Growing wellgrowth potential 0.84
Good:Temperature
Temperature22°C
Good:Wind
Wind light15 km/h
Sociable hours
A bit early or late, but fine

Limiting factor:temperature

Wednesday 2 September: Good. 8am–2pm — no rain in over a week, ground firm

Wednesday 2 September · 8am–2pmConfident

8am–2pm — no rain in over a week, ground firm

Good:Grass wetness
Grass dryno rain in over a week
Good:Ground firmness
Ground firm0mm rain over the last week
Good:Growth
Growing wellgrowth potential 0.97
Good:Temperature
Temperature13°C
Good:Wind
Wind light2 km/h
Sociable hours
A bit early or late, but finestarts when it stops being antisocial

Limiting factor:none

Thursday 3 September: Good. 8am–9pm — grass dry — rain earlier today

Thursday 3 September · 8am–9pmConfident

8am–9pm — grass dry — rain earlier today

Good:Grass wetness
Grass dryrain earlier today
Good:Ground firmness
Ground firm1mm rain over the last week
Good:Growth
Growing wellgrowth potential 0.61
Good:Temperature
Temperature10°C
Good:Wind
Wind light4 km/h
Sociable hours
A bit early or late, but finestarts once the dew has burnt off

Limiting factor:grass wetness

Friday 4 September: Marginal. No — 0.6mm of rain falling.

Friday 4 SeptemberConfident

No — 0.6mm of rain falling.

Poor:Grass wetness
Grass dampraining now
Good:Ground firmness
Ground firm2mm rain over the last week
Marginal:Growth
Growing slowlygrowth potential 0.30
Good:Temperature
Temperature12°C
Good:Wind
Wind light9 km/h

Limiting factor:grass wetness

Saturday 5 September: Good. 5pm–8pm — ground soft — 14mm rain over the last week

Saturday 5 September · 5pm–8pmReasonably confident

5pm–8pm — ground soft — 14mm rain over the last week

Marginal:Grass wetness
Grass dryrain earlier today
Poor:Ground firmness
Ground soft14mm rain over the last week
Poor:Growth
Growing slowlygrowth potential 0.21
Good:Temperature
Temperature11°C
Good:Wind
Wind light6 km/h
Sociable hours
A bit early or late, but fine

Limiting factor:ground firmness

Sunday 6 September: Good. 10am–9pm — growing slowly — growth potential 0.27

Sunday 6 September · 10am–9pmReasonably confident

10am–9pm — growing slowly — growth potential 0.27

Good:Grass wetness
Grass dryno rain since Friday
Good:Ground firmness
Ground firm36mm rain over the last week
Marginal:Growth
Growing slowlygrowth potential 0.27
Good:Temperature
Temperature12°C
Good:Wind
Wind light7 km/h
Sociable hours
Fine by the neighboursstarts when it stops being antisocial

Limiting factor:growth

Monday 7 September: Good. 8am–1pm — no rain since Friday, ground firm

Monday 7 September · 8am–1pmReasonably confident

8am–1pm — no rain since Friday, ground firm

Good:Grass wetness
Grass dryno rain since Friday
Good:Ground firmness
Ground firm36mm rain over the last week
Good:Growth
Growing steadilygrowth potential 0.38
Good:Temperature
Temperature11°C
Good:Wind
Wind light4 km/h
Sociable hours
A bit early or late, but finestarts at first light

Limiting factor:none

Tuesday 8 September: Good. 8am–7pm — rain earlier today, ground firm

Tuesday 8 September · 8am–7pmReasonably confident

8am–7pm — rain earlier today, ground firm

Good:Grass wetness
Grass dryrain earlier today
Good:Ground firmness
Ground firm36mm rain over the last week
Good:Growth
Growing steadilygrowth potential 0.38
Good:Temperature
Temperature11°C
Good:Wind
Wind light7 km/h
Sociable hours
A bit early or late, but finestarts at first light

Limiting factor:none

Wednesday 9 September: Not worth it. No — ground frozen.

Wednesday 9 SeptemberLow confidence this far out

No — ground frozen.

Good:Grass wetness
Grass dryrain earlier today
Good:Ground firmness
Ground firm36mm rain over the last week
Good:Growth
Growing wellgrowth potential 0.63
Good:Temperature
Temperature12°C
Good:Wind
Wind light4 km/h

Limiting factor:grass wetness

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 Wednesday
Good:Ground firmness
Ground firm36mm rain over the last week
Good:Growth
Growing wellgrowth potential 0.87
Good:Temperature
Temperature13°C
Good:Wind
Wind light8 km/h

Limiting factor:none

Soil temperature

24.9°C77°F

at 6cm — germination depth

Cooling over the next 11 days.

Too cold to seed — 24.9°C at 6cm and not warming.

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.

Soil temperature at 6cm for reliable germination. Sources onthe method page.
SpeciesSoil tempDays
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

What this means right now

  • Warning: Too cold to seed

    Too cold to seed — 24.9°C at 6cm and not warming.

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Forecast from Open-Meteo, refreshed hourly. Soil temperature is modelled, not measured — how that works and where the thresholds come from.