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SunnyDays

ERA5 almanac — 8 years of real data

Scottsdale in August

Historically one of the better months to visit Scottsdale for sun: 75% of days are clear on average (n=248, avg high 105°F). Every percentage here is a historical average from 8 years of ERA5 data — 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 Scottsdale 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 August

Clear-sky percentage for Scottsdale in August, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early August
1st–15th		 78% n=120 105°F
Late August
16th–end		 73% n=128 105°F
Full month average 75% n=248 105°F

Sunshine & warmth in August

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 Scottsdale in August. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early August
1st–15th		 100% n=120
Late August
16th–end		 99% n=128
Full month average 99% n=248
12.9 h median sunshine per day 97% of days exceed 8 h sunshine 14% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 75%. Sunshine-based “warm & sunny”: 99%. The 24-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

Scottsdale clears solidly in August: 75% of days historically (n=248), avg high 105°F. Most trips here in August will find more sun than cloud.

Every month in Scottsdale

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

Historical clear-sky % for Scottsdale, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 18% n=248 All destinations →
February 42% n=226 All destinations →
March 57% n=248 All destinations →
April 92% n=240 All destinations →
May 93% n=248 All destinations →
June 95% n=240 All destinations →
July 76% n=248 All destinations →
August ← this page 75% n=248 All destinations →
September 82% n=240 All destinations →
October 83% n=248 All destinations →
November 65% n=240 All destinations →
December 25% 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.