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SunnyDays

ERA5 almanac — 8 years of real data

Puerto Rico in March

Puerto Rico in March: 54% of days see measurable rain, 83°F average high, 15% of days historically clear (n=248, ERA5 2018–2025).

Puerto Rico in March is historically a poor month for sun: only 15% of days clear across 8 years (n=248, avg high 83°F). January is the clearest month for Puerto Rico 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 Puerto Rico 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 Puerto Rico 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 83°F
Late March
16th–end		 13% n=128 83°F
Full month average 15% n=248 83°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 Puerto Rico 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		 100% n=120
Late March
16th–end		 100% n=128
Full month average 100% n=248
11.3 h median sunshine per day 99% of days exceed 8 h sunshine 54% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 15%. Sunshine-based “warm & sunny”: 100%. The 85-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

Puerto Rico is a poor choice for sun in March: just 15% of days clear historically (n=248). January 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 January — historically the best month for sun in Puerto Rico.

Every month in Puerto Rico

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

Historical clear-sky % for Puerto Rico, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 15% n=248 All destinations →
February 15% n=226 All destinations →
March ← this page 15% n=248 All destinations →
April 10% n=240 All destinations →
May 7% n=248 All destinations →
June 15% n=240 All destinations →
July 9% n=248 All destinations →
August 8% n=248 All destinations →
September 4% n=240 All destinations →
October 9% n=248 All destinations →
November 11% n=240 All destinations →
December 14% n=248 All destinations →

Frequently asked

Does it rain in Puerto Rico in March?

Yes, frequently. In Puerto Rico, 54% of days in March see measurable rain, based on 8 years of ERA5 historical data (n=248 days, 2018–2025). This is a historical average, not a forecast.

Is Puerto Rico good for sun in March?

Not usually. Puerto Rico is historically overcast in March: only 15% of days are clear (avg high 83°F, n=248 days, ERA5 2018–2025). January is historically far better for sun here.

How Puerto Rico compares in March

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

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.