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SunnyDays

ERA5 almanac — 8 years of real data

Mérida in May

Mérida in May: rain frequency data not yet backfilled for this month, 97°F average high, 47% of days historically clear (n=248, ERA5 2018–2025).

Mérida in May is a mixed month for sun: 47% of days historically clear (n=248, avg high 97°F). The outcome varies year to year — check the early/late split below. Historical average, 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 Mérida 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 May

Clear-sky percentage for Mérida in May, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early May
1st–15th		 62% n=120 97°F
Late May
16th–end		 33% n=128 97°F
Full month average 47% n=248 97°F

Bottom line

Mérida in May is genuinely mixed: 47% of days historically clear (n=248), avg high 97°F — roughly even odds. The two halves differ materially (62% early, 33% late) — favour the early half of the month. The outcome varies year to year; don't book if you need guaranteed sun.

Every month in Mérida

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

Historical clear-sky % for Mérida, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 55% n=248 All destinations →
February 61% n=226 All destinations →
March 74% n=248 All destinations →
April 68% n=240 All destinations →
May ← this page 47% n=248 All destinations →
June 20% n=240 All destinations →
July 20% n=248 All destinations →
August 13% n=248 All destinations →
September 8% n=240 All destinations →
October 20% n=248 All destinations →
November 38% n=240 All destinations →
December 53% n=248 All destinations →

Frequently asked

Is Mérida good for sun in May?

It's mixed. Mérida in May is clear on 47% of days historically (avg high 97°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

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.