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SunnyDays

ERA5 almanac — 8 years of real data

Santorini in October

Santorini in October: 8% of days see measurable rain, 74°F average high, 59% of days historically clear (n=248, ERA5 2018–2025).

Santorini in October is a mixed month for sun: 59% 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 October

Clear-sky percentage for Santorini in October, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early October
1st–15th		 74% n=120 74°F
Late October
16th–end		 44% n=128 74°F
Full month average 59% n=248 74°F

Sunshine & warmth in October

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 Santorini in October. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early October
1st–15th		 91% n=120
Late October
16th–end		 53% n=128
Full month average 71% n=248
10.3 h median sunshine per day 96% of days exceed 8 h sunshine 8% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 59%. Sunshine-based “warm & sunny”: 71%. The 12-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

Santorini in October is genuinely mixed: 59% of days historically clear (n=248), avg high 74°F — more clear than cloudy. The two halves differ materially (74% early, 44% late) — favour the early 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 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 ← this page 59% n=248 All destinations →
November 16% n=240 All destinations →
December 0% n=248 All destinations →

Frequently asked

Does it rain in Santorini in October?

Rarely. Only 8% of days in Santorini see measurable rain in October, based on 8 years of ERA5 historical data (n=248 days, 2018–2025). This is a historical average, not a forecast.

Is Santorini good for sun in October?

It's mixed. Santorini in October is clear on 59% of days historically (avg high 74°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

How Santorini compares in October

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