ERA5 almanac — 8 years of real data

Marfa in July

Marfa in July: 16% of days see measurable rain, 91°F average high, 61% of days historically clear (n=248, ERA5 2018–2025).

Marfa in July is a mixed month for sun: 61% of days historically clear (n=248, avg high 91°F). The outcome varies year to year — check the early/late split below. 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 July

Clear-sky percentage for Marfa 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	52%	n=120	91°F
Late July 16th–end	69%	n=128	91°F
Full month average	61%	n=248	91°F

Sunshine & warmth in July

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 July. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period	Warm & sunny (≥72°F, >6 h sun)	Sample (n)
Early July 1st–15th	100%	n=120
Late July 16th–end	100%	n=128
Full month average	100%	n=248

13.6 h median sunshine per day 100% of days exceed 8 h sunshine 16% of days see ≥ 1 mm rain — rain is not hidden

Comparison (old vs new): WMO-code “clear” bar: 61%. Sunshine-based “warm & sunny”: 100%. The 39-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

Marfa clears solidly in July: 61% of days historically (n=248), avg high 91°F. Most trips here in July will find more sun than cloud.

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 ← this page	61%	n=248	All destinations →
August	60%	n=248	All destinations →
September	64%	n=240	All destinations →
October	69%	n=248	All destinations →
November	34%	n=240	All destinations →
December	11%	n=248	All destinations →

Frequently asked

Does it rain in Marfa in July?

Rarely. Only 16% of days in Marfa see measurable rain in July, based on 8 years of ERA5 historical data (n=248 days, 2018–2025). This is a historical average, not a forecast.

Is Marfa good for sun in July?

Yes. Marfa is historically strong for sun in July: 61% of days are clear on average (avg high 91°F, n=248 days, ERA5 2018–2025).

How Marfa compares in July

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

→ Marfa vs Jackson Hole in July — Jackson Hole is 62% clear historically
→ Marfa vs Sedona in July — Sedona is 64% clear historically
→ Marfa vs Steamboat Springs in July — Steamboat Springs is 64% clear historically

→ Marfa live forecast — this week’s actual 7-day weather, not historical
→ Best destinations in July — all destinations ranked by July 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.