ERA5 almanac comparison — 8 years of real data

Orlando vs St. Barthélemy: weather in September

Essentially a tie in September: Orlando is 10% clear historically, St. Barthélemy is 13% clear (8-year ERA5 average) — within the noise. Avg high 86°F vs 84°F. Orlando also sees measurably more rain than St. Barthélemy this month (72% vs 56% of days). Pick based on flight time or price, not weather — the weather won't decide this one for you.

What you are reading: 8-year historical averages, not a forecast. Either destination can still surprise you this specific September. For this week’s actual forecast, each destination links to its live page below.

Orlando

Clear days, September: 10%
Sample size: n=240 days
Avg high: 86°F
Early September (1st–15th): 8%
Late September (16th–end): 13%
Rain frequency: 72% of days

St. Barthélemy

Clear days, September: 13%
Sample size: n=240 days
Avg high: 84°F
Early September (1st–15th): 14%
Late September (16th–end): 12%
Rain frequency: 56% of days

Compare Orlando vs St. Barthélemy in another month

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.