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SunnyDays

ERA5 almanac — 8 years of real data

Vail in July

Vail in July is historically a poor month for sun: only 36% of days clear across 8 years (n=248, avg high 78°F). Historical average, not a forecast.

What you are reading: 8-year historical averages from the ERA5 reanalysis, not a forecast. A month that is historically 90% clear can still be overcast on your specific trip. For this week’s actual forecast, see the live Vail page. Both can be true at once: “historically strong in this month; this particular week is not.” We label which is which.

Early vs. Late July

Clear-sky percentage for Vail in July, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early July
1st–15th		 44% n=120 78°F
Late July
16th–end		 29% n=128 78°F
Full month average 36% n=248 78°F

Sunshine & warmth in July

A second measure using actual sunshine hours (ERA5 sunshine_duration), not the daily weather code. A Lowcountry day with 12 hours of sun and a 25-minute afternoon storm is counted below as a warm, sunny day — because it was. How we define this.

Sunshine-based metrics for Vail in July. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early July
1st–15th		 85% n=120
Late July
16th–end		 98% n=128
Full month average 92% n=248
13.9 h median sunshine per day 98% of days exceed 8 h sunshine 26% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 36%. Sunshine-based “warm & sunny”: 92%. The 56-point gap is from brief afternoon convective storms that stamp the whole day as “rain” in the WMO code but leave the bulk of the sunshine untouched.

Bottom line

Vail is mostly overcast in July historically: only 36% of days are clear across 8 years (n=248), avg high 78°F. Most visitors this month will see more clouds than sun.

Every month in Vail

Compare across all months with data. Numbers are historical clear-sky %.

Historical clear-sky % for Vail, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 0% n=226 All destinations →
March 0% n=248 All destinations →
April 0% n=240 All destinations →
May 0% n=248 All destinations →
June 30% n=240 All destinations →
July ← this page 36% n=248 All destinations →
August 46% n=248 All destinations →
September 23% n=240 All destinations →
October 0% n=248 All destinations →
November 0% n=240 All destinations →
December 0% n=248 All destinations →

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.