ERA5 almanac comparison — 8 years of real data
Cancún vs Kiawah Island: weather in December
Cancún edges out Kiawah Island for sun in December: 20% clear historically versus 4% (8-year ERA5 average, a 16-point gap). Cancún also sees measurably more rain than Kiawah Island this month (47% vs 29% of days). Both are viable — Cancún is the safer bet.
What you are reading: 8-year historical averages, not a forecast.
Either destination can still surprise you this specific December. For this
week’s actual forecast, each destination links to its live page below.
Cancún
MX
- Clear days, December
- 20%
- Sample size
- n=248 days
- Avg high
- 80°F
- Early December (1st–15th)
- 22%
- Late December (16th–end)
- 18%
- Rain frequency
- 47% of days
Kiawah Island
SC
- Clear days, December
- 4%
- Sample size
- n=248 days
- Avg high
- 62°F
- Early December (1st–15th)
- 2%
- Late December (16th–end)
- 5%
- Rain frequency
- 29% of days
Compare Cancún vs Kiawah Island 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.