ERA5 almanac comparison — 8 years of real data
Big Sky vs Montauk: weather in July
Montauk edges out Big Sky for sun in July: 29% clear historically versus 18% (8-year ERA5 average, a 11-point gap). Both are viable — Montauk is the safer bet.
What you are reading: 8-year historical averages, not a forecast.
Either destination can still surprise you this specific July. For this
week’s actual forecast, each destination links to its live page below.
Big Sky
MT
- Clear days, July
- 18%
- Sample size
- n=248 days
- Avg high
- 72°F
- Early July (1st–15th)
- 13%
- Late July (16th–end)
- 23%
Montauk
NY
- Clear days, July
- 29%
- Sample size
- n=248 days
- Avg high
- 73°F
- Early July (1st–15th)
- 16%
- Late July (16th–end)
- 41%
Compare Big Sky vs Montauk 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.