ERA5 almanac comparison — 8 years of real data
St. Barthélemy vs St. John, USVI: weather in August
Essentially a tie in August: St. Barthélemy is 14% clear historically, St. John, USVI is 13% clear (8-year ERA5 average) — within the noise. Avg high 84°F vs 80°F. 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 August. For this
week’s actual forecast, each destination links to its live page below.
St. Barthélemy
BL
- Clear days, August
- 14%
- Sample size
- n=248 days
- Avg high
- 84°F
- Early August (1st–15th)
- 10%
- Late August (16th–end)
- 18%
- Rain frequency
- 46% of days
St. John, USVI
VI
- Clear days, August
- 13%
- Sample size
- n=248 days
- Avg high
- 80°F
- Early August (1st–15th)
- 10%
- Late August (16th–end)
- 16%
- Rain frequency
- 51% of days
Compare St. Barthélemy vs St. John, USVI 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.