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SunnyDays

ERA5 almanac comparison — 8 years of real data

Big Sky vs Mazatlán: weather in August

Essentially a tie in August: Big Sky is 18% clear historically, Mazatlán is 16% clear (8-year ERA5 average) — within the noise. Avg high 70°F vs 87°F. Mazatlán also sees measurably more rain than Big Sky this month (63% vs 46% 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 August. For this week’s actual forecast, each destination links to its live page below.

Big Sky

MT

Clear days, August
18%
Sample size
n=248 days
Avg high
70°F
Early August (1st–15th)
20%
Late August (16th–end)
16%
Rain frequency
46% of days

Mazatlán

MX

Clear days, August
16%
Sample size
n=248 days
Avg high
87°F
Early August (1st–15th)
20%
Late August (16th–end)
13%
Rain frequency
63% of days

Compare Big Sky vs Mazatlán 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.