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SunnyDays

ERA5 almanac — 8 years of real data

Santorini in May

Santorini in May: rain frequency data not yet backfilled for this month, 74°F average high, 52% of days historically clear (n=248, ERA5 2018–2025).

Santorini in May is a mixed month for sun: 52% of days historically clear (n=248, avg high 74°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 Santorini 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 May

Clear-sky percentage for Santorini in May, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early May
1st–15th		 37% n=120 74°F
Late May
16th–end		 67% n=128 74°F
Full month average 52% n=248 74°F

Bottom line

Santorini in May is genuinely mixed: 52% of days historically clear (n=248), avg high 74°F — roughly even odds. The two halves differ materially (37% early, 67% late) — favour the late half of the month. The outcome varies year to year; don't book if you need guaranteed sun.

Every month in Santorini

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

Historical clear-sky % for Santorini, 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 14% n=240 All destinations →
May ← this page 52% n=248 All destinations →
June 89% n=240 All destinations →
July 95% n=248 All destinations →
August 93% n=248 All destinations →
September 86% n=240 All destinations →
October 59% n=248 All destinations →
November 16% n=240 All destinations →
December 0% n=248 All destinations →

Frequently asked

Is Santorini good for sun in May?

It's mixed. Santorini in May is clear on 52% of days historically (avg high 74°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

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.