ERA5 almanac comparison — 8 years of real data
Mexico City vs Tucson: weather in September
Tucson is the clear winner for sun in September: 70% of days historically clear versus just 4% in Mexico City — a 66-point gap across 8 years of ERA5 data. Mexico City also sees measurably more rain than Tucson this month (84% vs 20% of days). This isn't close.
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
Tucson
AZ
- Clear days, September
- 70%
- Sample size
- n=240 days
- Avg high
- 96°F
- Early September (1st–15th)
- 72%
- Late September (16th–end)
- 69%
- Rain frequency
- 20% of days
Frequently asked
Is Mexico City or Tucson warmer in September?
Tucson runs warmer by day in September. Mexico City averages highs of 73°F (highs n=240 days); Tucson averages highs of 96°F (highs n=240 days) (ERA5 2018–2025). Historical averages, not a forecast.
Does it rain more in Mexico City or Tucson in September?
Mexico City is measurably wetter than Tucson. Days with measurable rain: Mexico City 84%, Tucson 20% (n=240 and n=240 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in September, Mexico City or Tucson?
Tucson is the clear winner for sun in September: 70% of days historically clear versus just 4% in Mexico City — a 66-point gap across 8 years of ERA5 data. Mexico City also sees measurably more rain than Tucson this month (84% vs 20% of days). This isn't close.
Compare Mexico City vs Tucson 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.