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SunnyDays

ERA5 almanac — 8 years of real data

Nashville in April

Nashville in April is historically a poor month for sun: only 18% of days clear across 8 years (n=240, avg high 69°F). September is the clearest month for Nashville 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 Nashville 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 April

Clear-sky percentage for Nashville in April, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early April
1st–15th		 13% n=120 69°F
Late April
16th–end		 22% n=120 69°F
Full month average 18% n=240 69°F

Sunshine & warmth in April

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 Nashville in April. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early April
1st–15th		 29% n=120
Late April
16th–end		 40% n=120
Full month average 34% n=240
11.1 h median sunshine per day 73% of days exceed 8 h sunshine 41% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 18%. Sunshine-based “warm & sunny”: 34%. The 16-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

Nashville is a poor choice for sun in April: just 18% of days clear historically (n=240). September is the historically strongest month for sun here. The 8-year record is consistent — this is not a fluke bad stretch.

→ See all destinations in September — historically the best month for sun in Nashville.

Every month in Nashville

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

Historical clear-sky % for Nashville, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 1% n=226 All destinations →
March 8% n=248 All destinations →
April ← this page 18% n=240 All destinations →
May 28% n=248 All destinations →
June 30% n=240 All destinations →
July 19% n=248 All destinations →
August 32% n=248 All destinations →
September 48% n=240 All destinations →
October 32% n=248 All destinations →
November 6% 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.