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SunnyDays

ERA5 almanac — 8 years of real data

Las Vegas in March

Las Vegas in March is historically a poor month for sun: only 32% of days clear across 8 years (n=248, avg high 70°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 Las Vegas 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 Las Vegas 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		 18% n=120 70°F
Late March
16th–end		 45% n=128 70°F
Full month average 32% n=248 70°F

Sunshine & warmth in March

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 Las Vegas in March. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early March
1st–15th		 21% n=120
Late March
16th–end		 48% n=128
Full month average 35% n=248
11.3 h median sunshine per day 88% of days exceed 8 h sunshine 12% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 32%. Sunshine-based “warm & sunny”: 35%.

Bottom line

Las Vegas is mostly overcast in March historically: only 32% of days are clear across 8 years (n=248), avg high 70°F. The two halves differ materially (18% early, 45% late) — favour the late half of the month. Most visitors this month will see more clouds than sun.

Every month in Las Vegas

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

Historical clear-sky % for Las Vegas, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 15% n=226 All destinations →
March ← this page 32% n=248 All destinations →
April 84% n=240 All destinations →
May 88% n=248 All destinations →
June 95% n=240 All destinations →
July 88% n=248 All destinations →
August 85% n=248 All destinations →
September 92% n=240 All destinations →
October 82% n=248 All destinations →
November 34% n=240 All destinations →
December 0% 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.