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SunnyDays

ERA5 almanac — 8 years of real data

Houston in July

Houston in July is historically a poor month for sun: only 21% of days clear across 8 years (n=248, avg high 91°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 July

Clear-sky percentage for Houston in July, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early July
1st–15th		 13% n=120 91°F
Late July
16th–end		 29% n=128 91°F
Full month average 21% n=248 91°F

Bottom line

Houston is mostly overcast in July historically: only 21% of days are clear across 8 years (n=248), avg high 91°F. If you want sun in Houston, October is historically much better. Most visitors this month will see more clouds than sun.

→ 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 15% n=248 All destinations →
April 28% n=240 All destinations →
May 23% n=248 All destinations →
June 19% n=240 All destinations →
July ← this page 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.