ERA5 almanac comparison — 8 years of real data
Atlanta vs Sun Valley: weather in October
Atlanta is the clear winner for sun in October: 34% of days historically clear versus just 3% in Sun Valley — a 31-point gap across 8 years of ERA5 data. This isn't close.
What you are reading: 8-year historical averages, not a forecast.
Either destination can still surprise you this specific October. For this
week’s actual forecast, each destination links to its live page below.
Atlanta
GA
- Clear days, October
- 34%
- Sample size
- n=248 days
- Avg high
- 73°F
- Early October (1st–15th)
- 45%
- Late October (16th–end)
- 24%
Sun Valley
ID
- Clear days, October
- 3%
- Sample size
- n=248 days
- Avg high
- 55°F
- Early October (1st–15th)
- 6%
- Late October (16th–end)
- 0%
Compare Atlanta vs Sun Valley 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 7-day outlook for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.