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SunnyDays

ERA5 almanac — 8 years of real data

Houston in November

Houston in November is historically a poor month for sun: only 25% of days clear across 8 years (n=240, avg high 72°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 November

Clear-sky percentage for Houston in November, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early November
1st–15th		 32% n=120 72°F
Late November
16th–end		 18% n=120 72°F
Full month average 25% n=240 72°F

Sunshine & warmth in November

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 Houston in November. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early November
1st–15th		 56% n=120
Late November
16th–end		 38% n=120
Full month average 47% n=240
9.2 h median sunshine per day 62% of days exceed 8 h sunshine 38% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 25%. Sunshine-based “warm & sunny”: 47%. The 22-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

Houston is mostly overcast in November historically: only 25% of days are clear across 8 years (n=240), avg high 72°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 21% n=248 All destinations →
August 23% n=248 All destinations →
September 30% n=240 All destinations →
October 44% n=248 All destinations →
November ← this page 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.