ERA5 almanac comparison — 8 years of real data
Big Sur vs Missoula: weather in May
Missoula edges out Big Sur for sun in May: 22% clear historically versus 5% (8-year ERA5 average, a 17-point gap). Both are viable — Missoula is the safer bet.
What you are reading: 8-year historical averages, not a forecast.
Either destination can still surprise you this specific May. For this
week’s actual forecast, each destination links to its live page below.
Big Sur
CA
- Clear days, May
- 5%
- Sample size
- n=248 days
- Avg high
- 63°F
- Early May (1st–15th)
- 3%
- Late May (16th–end)
- 6%
- Rain frequency
- 10% of days
Missoula
MT
- Clear days, May
- 22%
- Sample size
- n=248 days
- Avg high
- 68°F
- Early May (1st–15th)
- 21%
- Late May (16th–end)
- 23%
Compare Big Sur vs Missoula 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.