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SunnyDays

ERA5 almanac — 8 years of real data

Tokyo in October

Tokyo in October: rain frequency data not yet backfilled for this month, 71°F average high, 21% of days historically clear (n=248, ERA5 2018–2025).

Tokyo in October is historically a poor month for sun: only 21% of days clear across 8 years (n=248, avg high 71°F). May is the clearest month for Tokyo 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 Tokyo 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 Tokyo 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		 34% n=120 71°F
Late October
16th–end		 9% n=128 71°F
Full month average 21% n=248 71°F

Bottom line

Tokyo is mostly overcast in October historically: only 21% of days are clear across 8 years (n=248), avg high 71°F. The two halves differ materially (34% early, 9% late) — favour the early half of the month. If you want sun in Tokyo, May is historically much better. Most visitors this month will see more clouds than sun.

→ See all destinations in May — historically the best month for sun in Tokyo.

Every month in Tokyo

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

Historical clear-sky % for Tokyo, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 0% n=226 All destinations →
March 3% n=248 All destinations →
April 12% n=240 All destinations →
May 32% n=248 All destinations →
June 27% n=240 All destinations →
July 27% n=248 All destinations →
August 29% n=248 All destinations →
September 26% n=240 All destinations →
October ← this page 21% n=248 All destinations →
November 2% n=240 All destinations →
December 0% n=248 All destinations →

Frequently asked

Is Tokyo good for sun in October?

Not usually. Tokyo is historically overcast in October: only 21% of days are clear (avg high 71°F, n=248 days, ERA5 2018–2025). May is historically far better for sun here.

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.