ERA5 almanac comparison — 8 years of real data
Costa Rica — Guanacaste vs Hilton Head: weather in May
Hilton Head is the clear winner for sun in May: 39% of days historically clear versus just 9% in Costa Rica — Guanacaste — a 30-point gap across 8 years of ERA5 data. Costa Rica — Guanacaste also sees measurably more rain than Hilton Head this month (78% vs 39% of days). This isn't close.
Costa Rica — Guanacaste
Costa Rica
- Clear days, May
- 9%
- Sample size
- n=248 days
- Avg high
- 91°F
- Early May (1st–15th)
- 13%
- Late May (16th–end)
- 5%
- Rain frequency
- 78% of days
Hilton Head
SC
- Clear days, May
- 39%
- Sample size
- n=248 days
- Avg high
- 81°F
- Early May (1st–15th)
- 44%
- Late May (16th–end)
- 35%
- Rain frequency
- 39% of days
Frequently asked
Is Costa Rica — Guanacaste or Hilton Head warmer in May?
Costa Rica — Guanacaste runs warmer by day in May. Costa Rica — Guanacaste averages highs of 91°F (highs n=248 days); Hilton Head averages highs of 81°F (highs n=248 days) (ERA5 2018–2025). Historical averages, not a forecast.
Does it rain more in Costa Rica — Guanacaste or Hilton Head in May?
Costa Rica — Guanacaste is measurably wetter than Hilton Head. Days with measurable rain: Costa Rica — Guanacaste 78%, Hilton Head 39% (n=248 and n=248 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in May, Costa Rica — Guanacaste or Hilton Head?
Hilton Head is the clear winner for sun in May: 39% of days historically clear versus just 9% in Costa Rica — Guanacaste — a 30-point gap across 8 years of ERA5 data. Costa Rica — Guanacaste also sees measurably more rain than Hilton Head this month (78% vs 39% of days). This isn't close.
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 forecast for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.