ERA5 almanac — 8 years of real data

Tulum in April

Tulum in April: 29% of days see measurable rain, 86°F average high, 30% of days historically clear (n=240, ERA5 2018–2025).

Tulum in April is historically a poor month for sun: only 30% of days clear across 8 years (n=240, avg high 86°F). 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 Tulum 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 April

Clear-sky percentage for Tulum in April, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period	% Clear days	Sample (n)	Avg high
Early April 1st–15th	30%	n=120	86°F
Late April 16th–end	30%	n=120	86°F
Full month average	30%	n=240	86°F

Sunshine & warmth in April

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 Tulum in April. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period	Warm & sunny (≥72°F, >6 h sun)	Sample (n)
Early April 1st–15th	98%	n=120
Late April 16th–end	100%	n=120
Full month average	99%	n=240

12.0 h median sunshine per day 99% of days exceed 8 h sunshine 29% of days see ≥ 1 mm rain — rain is not hidden

Comparison (old vs new): WMO-code “clear” bar: 30%. Sunshine-based “warm & sunny”: 99%. The 69-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

Tulum is mostly overcast in April historically: only 30% of days are clear across 8 years (n=240), avg high 86°F. Most visitors this month will see more clouds than sun.

Every month in Tulum

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

Historical clear-sky % for Tulum, all months, ERA5 2018–2025.
Month	% Clear	Sample (n)
January	23%	n=248	All destinations →
February	23%	n=226	All destinations →
March	28%	n=248	All destinations →
April ← this page	30%	n=240	All destinations →
May	16%	n=248	All destinations →
June	6%	n=240	All destinations →
July	11%	n=248	All destinations →
August	8%	n=248	All destinations →
September	4%	n=240	All destinations →
October	11%	n=248	All destinations →
November	20%	n=240	All destinations →
December	21%	n=248	All destinations →

Frequently asked

Does it rain in Tulum in April?

Sometimes. Tulum sees measurable rain on 29% of days in April historically (n=240 days, ERA5 2018–2025) — not frequent enough to plan around, but not negligible either.

Is Tulum good for sun in April?

It's mixed. Tulum in April is clear on 30% of days historically (avg high 86°F, n=240 days, ERA5 2018–2025) — the outcome varies year to year.

How Tulum compares in April

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

→ Tulum vs Gulf Shores in April — Gulf Shores is 30% clear historically
→ Tulum vs Nassau in April — Nassau is 30% clear historically
→ Tulum vs Fort Lauderdale in April — Fort Lauderdale is 29% clear historically

→ Tulum live forecast — this week’s actual 7-day weather, not historical
→ Best destinations in April — all destinations ranked by April clear-sky %
→ All destinations
→ Raw data (JSON) — buckets, n, source

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.