ERA5 almanac — 8 years of real data

Maui in January

Maui in January: rain frequency data not yet backfilled for this month, 72°F average high, 25% of days historically clear (n=248, ERA5 2018–2025).

Maui in January is historically a poor month for sun: only 25% of days clear across 8 years (n=248, avg high 72°F). August is the clearest month for Maui 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 Maui 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 January

Clear-sky percentage for Maui in January, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period	% Clear days	Sample (n)	Avg high
Early January 1st–15th	28%	n=120	72°F
Late January 16th–end	22%	n=128	72°F
Full month average	25%	n=248	72°F

Bottom line

Maui is mostly overcast in January historically: only 25% of days are clear across 8 years (n=248), avg high 72°F. If you want sun in Maui, August is historically much better. Most visitors this month will see more clouds than sun.

→ See all destinations in August — historically the best month for sun in Maui.

Every month in Maui

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

Historical clear-sky % for Maui, all months, ERA5 2018–2025.
Month	% Clear	Sample (n)
January ← this page	25%	n=248	All destinations →
February	16%	n=226	All destinations →
March	15%	n=248	All destinations →
April	19%	n=240	All destinations →
May	26%	n=248	All destinations →
June	40%	n=240	All destinations →
July	33%	n=248	All destinations →
August	43%	n=248	All destinations →
September	34%	n=240	All destinations →
October	28%	n=248	All destinations →
November	30%	n=240	All destinations →
December	30%	n=248	All destinations →

Frequently asked

Is Maui good for sun in January?

Not usually. Maui is historically overcast in January: only 25% of days are clear (avg high 72°F, n=248 days, ERA5 2018–2025). August is historically far better for sun here.

→ Maui live forecast — this week’s actual 7-day weather, not historical
→ Best destinations in January — all destinations ranked by January clear-sky %
→ All destinations
→ Raw data (JSON) — buckets, n, source

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.