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SunnyDays

ERA5 almanac comparison — 8 years of real data

Denver vs Sun Valley: weather in January

Essentially a tie in January: Denver is 0% clear historically, Sun Valley is 0% clear (8-year ERA5 average) — within the noise. Avg high 41°F vs 32°F. Sun Valley also sees measurably more rain than Denver this month (33% vs 16% of days). Pick based on flight time or price, not weather — the weather won't decide this one for you.

What you are reading: 8-year historical averages, not a forecast. Either destination can still surprise you this specific January. For this week’s actual forecast, each destination links to its live page below.

Denver

CO

Clear days, January
0%
Sample size
n=248 days
Avg high
41°F
Early January (1st–15th)
0%
Late January (16th–end)
0%
Rain frequency
16% of days
See this week’s live forecast →

Sun Valley

ID

Clear days, January
0%
Sample size
n=248 days
Avg high
32°F
Early January (1st–15th)
0%
Late January (16th–end)
0%
Rain frequency
33% of days
See this week’s live forecast →

Compare Denver 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.