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SunnyDays

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 the actual forecast right now, 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
See the live forecast →

Mexico City

Mexico

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

Frequently asked

Is Carmel-by-the-Sea or Mexico City warmer in September?

Mexico City runs warmer by day in September. Carmel-by-the-Sea averages highs of 67°F (highs n=240 days); Mexico City averages highs of 73°F (highs n=240 days) (ERA5 2018–2025). Historical averages, not a forecast.

Does it rain more in Carmel-by-the-Sea or Mexico City in September?

Mexico City is measurably wetter than Carmel-by-the-Sea. Days with measurable rain: Carmel-by-the-Sea 5%, Mexico City 84% (n=240 and n=240 days). ERA5 2018–2025; historical, not a forecast.

Which is sunnier in September, Carmel-by-the-Sea or Mexico City?

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.

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 forecast for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.