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SunnyDays

ERA5 almanac — 8 years of real data

Oaxaca in December

Oaxaca in December: 2% of days see measurable rain, 77°F average high, 84% of days historically clear (n=248, ERA5 2018–2025).

Historically one of the better months to visit Oaxaca for sun: 84% of days are clear on average (n=248, avg high 77°F). Every percentage here is a historical average from 8 years of ERA5 data — not a forecast.

What you are reading: 8-year historical averages from the ERA5 reanalysis, not a forecast. A month that is historically 90% clear can still be overcast on your specific trip. For this week’s actual forecast, see the live Oaxaca page. Both can be true at once: “historically strong in this month; this particular week is not.” We label which is which.

Early vs. Late December

Clear-sky percentage for Oaxaca in December, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early December
1st–15th		 83% n=120 77°F
Late December
16th–end		 84% n=128 77°F
Full month average 84% n=248 77°F

Sunshine & warmth in December

A second measure using actual sunshine hours (ERA5 sunshine_duration), not the daily weather code. A Lowcountry day with 12 hours of sun and a 25-minute afternoon storm is counted below as a warm, sunny day — because it was. How we define this.

Sunshine-based metrics for Oaxaca in December. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early December
1st–15th		 97% n=120
Late December
16th–end		 93% n=128
Full month average 95% n=248
10.9 h median sunshine per day 98% of days exceed 8 h sunshine 2% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 84%. Sunshine-based “warm & sunny”: 95%. The 11-point gap is from brief afternoon convective storms that stamp the whole day as “rain” in the WMO code but leave the bulk of the sunshine untouched.

Bottom line

Oaxaca is historically one of the best destinations for sun in December: 84% of days meet the clear bar (avg high 77°F, n=248 days across 8 years). Pack for outdoor activity — this month consistently delivers.

Every month in Oaxaca

Compare across all months with data. Numbers are historical clear-sky %.

Historical clear-sky % for Oaxaca, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 82% n=248 All destinations →
February 90% n=226 All destinations →
March 86% n=248 All destinations →
April 70% n=240 All destinations →
May 45% n=248 All destinations →
June 16% n=240 All destinations →
July 9% n=248 All destinations →
August 6% n=248 All destinations →
September 6% n=240 All destinations →
October 28% n=248 All destinations →
November 68% n=240 All destinations →
December ← this page 84% n=248 All destinations →

Frequently asked

Does it rain in Oaxaca in December?

Rarely. Only 2% of days in Oaxaca see measurable rain in December, based on 8 years of ERA5 historical data (n=248 days, 2018–2025). This is a historical average, not a forecast.

Is Oaxaca good for sun in December?

Yes. Oaxaca is historically strong for sun in December: 84% of days are clear on average (avg high 77°F, n=248 days, ERA5 2018–2025).

How Oaxaca compares in December

Head-to-head clear-sky comparisons against destinations travelers plausibly weigh against Oaxaca this month — same passport tier, similar flight distance, both sides from the same 8-year ERA5 record.

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.