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SunnyDays

ERA5 almanac — 8 years of real data

Houston in March

Houston in March is historically a poor month for sun: only 15% of days clear across 8 years (n=248, avg high 74°F). October is the clearest month for Houston historically. 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 Houston 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 March

Clear-sky percentage for Houston in March, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early March
1st–15th		 8% n=120 74°F
Late March
16th–end		 22% n=128 74°F
Full month average 15% n=248 74°F

Bottom line

Houston is a poor choice for sun in March: just 15% of days clear historically (n=248). October is the historically strongest month for sun here. The 8-year record is consistent — this is not a fluke bad stretch.

→ See all destinations in October — historically the best month for sun in Houston.

Every month in Houston

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

Historical clear-sky % for Houston, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 2% n=248 All destinations →
February 6% n=226 All destinations →
March ← this page 15% n=248 All destinations →
April 28% n=240 All destinations →
May 23% n=248 All destinations →
June 19% n=240 All destinations →
July 21% n=248 All destinations →
August 23% n=248 All destinations →
September 30% n=240 All destinations →
October 44% n=248 All destinations →
November 25% n=240 All destinations →
December 6% n=248 All destinations →

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.