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SunnyDays

ERA5 almanac — 8 years of real data

Marfa in November

Marfa in November is historically a poor month for sun: only 34% of days clear across 8 years (n=240, avg high 68°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 Marfa 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 Marfa 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		 52% n=120 68°F
Late November
16th–end		 17% n=120 68°F
Full month average 34% n=240 68°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 Marfa 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		 55% n=120
Late November
16th–end		 18% n=120
Full month average 36% n=240
10.2 h median sunshine per day 90% of days exceed 8 h sunshine 8% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 34%. Sunshine-based “warm & sunny”: 36%. The two measures are nearly identical here — no convective-storm bias for this climate and month.

Bottom line

Marfa is mostly overcast in November historically: only 34% of days are clear across 8 years (n=240), avg high 68°F. The two halves differ materially (52% early, 17% late) — favour the early half of the month. Most visitors this month will see more clouds than sun.

Every month in Marfa

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

Historical clear-sky % for Marfa, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 1% n=248 All destinations →
February 19% n=226 All destinations →
March 48% n=248 All destinations →
April 78% n=240 All destinations →
May 73% n=248 All destinations →
June 70% n=240 All destinations →
July 61% n=248 All destinations →
August 60% n=248 All destinations →
September 64% n=240 All destinations →
October 69% n=248 All destinations →
November ← this page 34% n=240 All destinations →
December 11% 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.