ERA5 almanac comparison — 8 years of real data
Birmingham vs Costa Rica — Guanacaste: weather in August
Birmingham edges out Costa Rica — Guanacaste for sun in August: 28% clear historically versus 6% (8-year ERA5 average, a 22-point gap). Costa Rica — Guanacaste also sees measurably more rain than Birmingham this month (71% vs 48% of days). Both are viable — Birmingham is the safer bet.
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.
Birmingham
AL
- Clear days, August
- 28%
- Sample size
- n=248 days
- Avg high
- 88°F
- Early August (1st–15th)
- 22%
- Late August (16th–end)
- 34%
- Rain frequency
- 48% of days
Costa Rica — Guanacaste
CR
- Clear days, August
- 6%
- Sample size
- n=248 days
- Avg high
- 88°F
- Early August (1st–15th)
- 8%
- Late August (16th–end)
- 5%
- Rain frequency
- 71% of days
Compare Birmingham vs Costa Rica — Guanacaste 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.