ERA5 almanac comparison — 8 years of real data
Denver vs Hartford: weather in October
Denver edges out Hartford for sun in October: 38% clear historically versus 11% (8-year ERA5 average, a 27-point gap). Both are viable — Denver is the safer bet.
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.
Denver
CO
- Clear days, October
- 38%
- Sample size
- n=248 days
- Avg high
- 68°F
- Early October (1st–15th)
- 48%
- Late October (16th–end)
- 28%
Hartford
CT
- Clear days, October
- 11%
- Sample size
- n=248 days
- Avg high
- 64°F
- Early October (1st–15th)
- 15%
- Late October (16th–end)
- 7%
Compare Denver vs Hartford 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.