ERA5 almanac comparison — 8 years of real data
Cancún vs St. Augustine: weather in September
St. Augustine edges out Cancún for sun in September: 17% clear historically versus 5% (8-year ERA5 average, a 12-point gap). Both are viable — St. Augustine is the safer bet.
Cancún
Mexico
- Clear days, September
- 5%
- Sample size
- n=240 days
- Avg high
- 88°F
- Early September (1st–15th)
- 5%
- Late September (16th–end)
- 5%
- Rain frequency
- 71% of days
St. Augustine
FL
- Clear days, September
- 17%
- Sample size
- n=240 days
- Avg high
- 83°F
- Early September (1st–15th)
- 11%
- Late September (16th–end)
- 23%
- Rain frequency
- 64% of days
Frequently asked
Is Cancún or St. Augustine warmer in September?
Cancún runs warmer by day in September. Cancún averages highs of 88°F (highs n=240 days); St. Augustine averages highs of 83°F (highs n=240 days) (ERA5 2018–2025). Historical averages, not a forecast.
Does it rain more in Cancún or St. Augustine in September?
Days with measurable rain: Cancún 71%, St. Augustine 64% (n=240 and n=240 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in September, Cancún or St. Augustine?
St. Augustine edges out Cancún for sun in September: 17% clear historically versus 5% (8-year ERA5 average, a 12-point gap). Both are viable — St. Augustine is the safer bet.
Compare Cancún vs St. Augustine 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.