ERA5 almanac comparison — 8 years of real data

Huatulco vs Oaxaca: weather in September

Essentially a tie in September: Huatulco is 4% clear historically, Oaxaca is 6% clear (8-year ERA5 average) — within the noise. Avg high 84°F vs 77°F. Huatulco also sees measurably more rain than Oaxaca this month (90% vs 72% of days). 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 September. For this week’s actual forecast, each destination links to its live page below.

Huatulco

Clear days, September: 4%
Sample size: n=240 days
Avg high: 84°F
Early September (1st–15th): 5%
Late September (16th–end): 4%
Rain frequency: 90% of days

Oaxaca

Clear days, September: 6%
Sample size: n=240 days
Avg high: 77°F
Early September (1st–15th): 5%
Late September (16th–end): 8%
Rain frequency: 72% of days

Compare Huatulco vs Oaxaca 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.