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SunnyDays

ERA5 almanac — 8 years of real data

Madrid in September

Madrid in September: 20% of days see measurable rain, 80°F average high, 62% of days historically clear (n=240, ERA5 2018–2025).

Madrid in September is a mixed month for sun: 62% of days historically clear (n=240, avg high 80°F). The outcome varies year to year — check the early/late split below. 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 Madrid 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 September

Clear-sky percentage for Madrid in September, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early September
1st–15th		 68% n=120 80°F
Late September
16th–end		 56% n=120 80°F
Full month average 62% n=240 80°F

Sunshine & warmth in September

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 Madrid in September. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early September
1st–15th		 92% n=120
Late September
16th–end		 81% n=120
Full month average 86% n=240
11.9 h median sunshine per day 90% of days exceed 8 h sunshine 20% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 62%. Sunshine-based “warm & sunny”: 86%. The 24-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

Madrid clears solidly in September: 62% of days historically (n=240), avg high 80°F. Most trips here in September will find more sun than cloud.

Every month in Madrid

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

Historical clear-sky % for Madrid, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 0% n=226 All destinations →
March 9% n=248 All destinations →
April 20% n=240 All destinations →
May 51% n=248 All destinations →
June 67% n=240 All destinations →
July 91% n=248 All destinations →
August 88% n=248 All destinations →
September ← this page 62% n=240 All destinations →
October 38% n=248 All destinations →
November 0% n=240 All destinations →
December 0% n=248 All destinations →

Frequently asked

Does it rain in Madrid in September?

Sometimes. Madrid sees measurable rain on 20% of days in September historically (n=240 days, ERA5 2018–2025) — not frequent enough to plan around, but not negligible either.

Is Madrid good for sun in September?

Yes. Madrid is historically strong for sun in September: 62% of days are clear on average (avg high 80°F, n=240 days, ERA5 2018–2025).

How Madrid compares in September

Head-to-head clear-sky comparisons against destinations travelers plausibly weigh against Madrid 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.