Skip to main content
SunnyDays

ERA5 almanac — 8 years of real data

Tampa in September

Tampa in September: 67% of days see measurable rain, 87°F average high, 12% of days historically clear (n=240, ERA5 2018–2025).

Tampa in September is historically a poor month for sun: only 12% of days clear across 8 years (n=240, avg high 87°F). April is the clearest month for Tampa 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 Tampa 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 September

Clear-sky percentage for Tampa in September, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early September
1st–15th		 6% n=120 87°F
Late September
16th–end		 18% n=120 87°F
Full month average 12% n=240 87°F

Sunshine & warmth in September

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 Tampa in September. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early September
1st–15th		 92% n=120
Late September
16th–end		 91% n=120
Full month average 92% n=240
11.1 h median sunshine per day 83% of days exceed 8 h sunshine 67% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 12%. Sunshine-based “warm & sunny”: 92%. The 80-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

Tampa is a poor choice for sun in September: just 12% of days clear historically (n=240). April 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 April — historically the best month for sun in Tampa.

Every month in Tampa

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

Historical clear-sky % for Tampa, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 23% n=248 All destinations →
February 40% n=226 All destinations →
March 52% n=248 All destinations →
April 54% n=240 All destinations →
May 38% n=248 All destinations →
June 6% n=240 All destinations →
July 2% n=248 All destinations →
August 2% n=248 All destinations →
September ← this page 12% n=240 All destinations →
October 41% n=248 All destinations →
November 41% n=240 All destinations →
December 34% n=248 All destinations →

Frequently asked

Does it rain in Tampa in September?

Yes, frequently. In Tampa, 67% of days in September see measurable rain, based on 8 years of ERA5 historical data (n=240 days, 2018–2025). This is a historical average, not a forecast.

Is Tampa good for sun in September?

Not usually. Tampa is historically overcast in September: only 12% of days are clear (avg high 87°F, n=240 days, ERA5 2018–2025). April is historically far better for sun here.

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.