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SunnyDays

ERA5 almanac comparison — 8 years of real data

Costa Rica — Guanacaste vs Mexico City: weather in July

Costa Rica — Guanacaste edges out Mexico City for sun in July: 16% clear historically versus 1% (8-year ERA5 average, a 15-point gap). Mexico City also sees measurably more rain than Costa Rica — Guanacaste this month (90% vs 63% of days). Both are viable — Costa Rica — Guanacaste is the safer bet.

What you are reading: 8-year historical averages, not a forecast. Either destination can still surprise you this specific July. For this week’s actual forecast, each destination links to its live page below.

Costa Rica — Guanacaste

CR

Clear days, July
16%
Sample size
n=248 days
Avg high
88°F
Early July (1st–15th)
9%
Late July (16th–end)
23%
Rain frequency
63% of days

Mexico City

MX

Clear days, July
1%
Sample size
n=248 days
Avg high
74°F
Early July (1st–15th)
0%
Late July (16th–end)
1%
Rain frequency
90% of days

Compare Costa Rica — Guanacaste 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.