ERA5 almanac comparison — 8 years of real data
Carmel-by-the-Sea vs Mexico City: weather in September
Carmel-by-the-Sea edges out Mexico City for sun in September: 10% clear historically versus 4% (8-year ERA5 average, a 6-point gap). Mexico City also sees measurably more rain than Carmel-by-the-Sea this month (84% vs 5% of days). Both are viable — Carmel-by-the-Sea is the safer bet.
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.
Carmel-by-the-Sea
CA
- Clear days, September
- 10%
- Sample size
- n=240 days
- Avg high
- 67°F
- Early September (1st–15th)
- 9%
- Late September (16th–end)
- 10%
- Rain frequency
- 5% of days
Mexico City
MX
- Clear days, September
- 4%
- Sample size
- n=240 days
- Avg high
- 73°F
- Early September (1st–15th)
- 2%
- Late September (16th–end)
- 6%
- Rain frequency
- 84% of days
Compare Carmel-by-the-Sea vs Mexico City 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.