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SunnyDays

ERA5 almanac — 8 years of real data

Denver in April

Denver in April: 24% of days see measurable rain, 64°F average high, 22% of days historically clear (n=240, ERA5 2018–2025).

Denver in April is historically a poor month for sun: only 22% of days clear across 8 years (n=240, avg high 64°F). September is the clearest month for Denver historically. 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 Denver 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 April

Clear-sky percentage for Denver in April, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early April
1st–15th		 20% n=120 64°F
Late April
16th–end		 24% n=120 64°F
Full month average 22% n=240 64°F

Sunshine & warmth in April

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 Denver in April. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early April
1st–15th		 22% n=120
Late April
16th–end		 28% n=120
Full month average 25% n=240
11.9 h median sunshine per day 84% of days exceed 8 h sunshine 24% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 22%. Sunshine-based “warm & sunny”: 25%.

Bottom line

Denver is mostly overcast in April historically: only 22% of days are clear across 8 years (n=240), avg high 64°F. If you want sun in Denver, September is historically much better. Most visitors this month will see more clouds than sun.

→ See all destinations in September — historically the best month for sun in Denver.

Every month in Denver

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

Historical clear-sky % for Denver, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 0% n=226 All destinations →
March 2% n=248 All destinations →
April ← this page 22% n=240 All destinations →
May 33% n=248 All destinations →
June 56% n=240 All destinations →
July 52% n=248 All destinations →
August 59% n=248 All destinations →
September 74% n=240 All destinations →
October 38% n=248 All destinations →
November 6% n=240 All destinations →
December 1% n=248 All destinations →

Frequently asked

Does it rain in Denver in April?

Sometimes. Denver sees measurable rain on 24% of days in April historically (n=240 days, ERA5 2018–2025) — not frequent enough to plan around, but not negligible either.

Is Denver good for sun in April?

Not usually. Denver is historically overcast in April: only 22% of days are clear (avg high 64°F, n=240 days, ERA5 2018–2025). September is historically far better for sun here.

How Denver compares in April

Head-to-head clear-sky comparisons against destinations travelers plausibly weigh against Denver this month — same passport tier, similar flight distance, both sides from the same 8-year ERA5 record.

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.