ERA5 almanac — 8 years of real data

St. Barthélemy in March

St. Barthélemy in March: rain frequency data not yet backfilled for this month, 79°F average high, 29% of days historically clear (n=248, ERA5 2018–2025).

St. Barthélemy in March is historically a poor month for sun: only 29% of days clear across 8 years (n=248, avg high 79°F). 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 St. Barthélemy 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 March

Clear-sky percentage for St. Barthélemy in March, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period	% Clear days	Sample (n)	Avg high
Early March 1st–15th	40%	n=120	79°F
Late March 16th–end	19%	n=128	79°F
Full month average	29%	n=248	79°F

Bottom line

St. Barthélemy is mostly overcast in March historically: only 29% of days are clear across 8 years (n=248), avg high 79°F. The two halves differ materially (40% early, 19% late) — favour the early half of the month. Most visitors this month will see more clouds than sun.

Every month in St. Barthélemy

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

Historical clear-sky % for St. Barthélemy, all months, ERA5 2018–2025.
Month	% Clear	Sample (n)
January	18%	n=248	All destinations →
February	12%	n=226	All destinations →
March ← this page	29%	n=248	All destinations →
April	22%	n=240	All destinations →
May	21%	n=248	All destinations →
June	19%	n=240	All destinations →
July	10%	n=248	All destinations →
August	14%	n=248	All destinations →
September	13%	n=240	All destinations →
October	20%	n=248	All destinations →
November	19%	n=240	All destinations →
December	18%	n=248	All destinations →

Frequently asked

Is St. Barthélemy good for sun in March?

Not usually. St. Barthélemy is historically overcast in March: only 29% of days are clear (avg high 79°F, n=248 days, ERA5 2018–2025).

→ St. Barthélemy live forecast — this week’s actual 7-day weather, not historical
→ Best destinations in March — all destinations ranked by March 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.