ERA5 almanac comparison — 8 years of real data
Coeur d'Alene vs Phoenix: weather in September
Phoenix is the clear winner for sun in September: 82% of days historically clear versus just 50% in Coeur d'Alene — a 32-point gap across 8 years of ERA5 data. This isn't close.
Coeur d'Alene
ID
- Clear days, September
- 50%
- Sample size
- n=240 days
- Avg high
- 75°F
- Early September (1st–15th)
- 68%
- Late September (16th–end)
- 33%
- Rain frequency
- 20% of days
Phoenix
AZ
- Clear days, September
- 82%
- Sample size
- n=240 days
- Avg high
- 101°F
- Early September (1st–15th)
- 82%
- Late September (16th–end)
- 81%
- Rain frequency
- 10% of days
Frequently asked
Is Coeur d'Alene or Phoenix warmer in September?
Phoenix runs warmer by day in September. Coeur d'Alene averages highs of 75°F (highs n=240 days); Phoenix averages highs of 101°F (highs n=240 days) (ERA5 2018–2025). Historical averages, not a forecast.
Does it rain more in Coeur d'Alene or Phoenix in September?
Days with measurable rain: Coeur d'Alene 20%, Phoenix 10% (n=240 and n=240 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in September, Coeur d'Alene or Phoenix?
Phoenix is the clear winner for sun in September: 82% of days historically clear versus just 50% in Coeur d'Alene — a 32-point gap across 8 years of ERA5 data. This isn't close.
Compare Coeur d'Alene vs Phoenix in another month
All percentages are historical averages from the ERA5 reanalysis via Open-Meteo, 8 full years (2018–2025). “Clear” means avg high ≥ 72 °F, precipitation < 1 mm, and a non-precipitation weather code. This is history, not a forecast. The live forecast for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.