ERA5 almanac comparison — 8 years of real data
Costa Rica — Guanacaste vs Hilton Head: weather in July
Essentially a tie in July: Costa Rica — Guanacaste is 16% clear historically, Hilton Head is 15% clear (8-year ERA5 average) — within the noise. Avg high 88°F vs 88°F. 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 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
Hilton Head
SC
- Clear days, July
- 15%
- Sample size
- n=248 days
- Avg high
- 88°F
- Early July (1st–15th)
- 13%
- Late July (16th–end)
- 16%
- Rain frequency
- 64% of days
Compare Costa Rica — Guanacaste vs Hilton Head 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.