ERA5 almanac comparison — 8 years of real data
Savannah vs St. John, USVI: weather in September
Savannah edges out St. John, USVI for sun in September: 32% clear historically versus 15% (8-year ERA5 average, a 17-point gap). Both are viable — Savannah is the safer bet.
Savannah
GA
- Clear days, September
- 32%
- Sample size
- n=240 days
- Avg high
- 85°F
- Early September (1st–15th)
- 28%
- Late September (16th–end)
- 37%
- Rain frequency
- 50% of days
St. John, USVI
VI
- Clear days, September
- 15%
- Sample size
- n=240 days
- Avg high
- 80°F
- Early September (1st–15th)
- 16%
- Late September (16th–end)
- 14%
- Rain frequency
- 56% of days
Frequently asked
Is Savannah or St. John, USVI warmer in September?
Savannah runs warmer by day in September. Savannah averages highs of 85°F (highs n=240 days); St. John, USVI averages highs of 80°F (highs n=240 days) (ERA5 2018–2025). Historical averages, not a forecast.
Does it rain more in Savannah or St. John, USVI in September?
Days with measurable rain: Savannah 50%, St. John, USVI 56% (n=240 and n=240 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in September, Savannah or St. John, USVI?
Savannah edges out St. John, USVI for sun in September: 32% clear historically versus 15% (8-year ERA5 average, a 17-point gap). Both are viable — Savannah is the safer bet.
Compare Savannah 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 forecast for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.