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San Juan weather by month

San Juan runs from about 25°C in February to 28°C in August, with November the wettest month at 257 mm.

warmest month

August

28°C

coolest month

February

25°C

wettest month

November

257 mm

worst air month

June

10 µg/m³

The whole year, month by month.

Monthly climate normals for San Juan
MonthAvg tempRainSunPM2.5
January26°C42 mm331 h4
February25°C147 mm296 h6
March25°C59 mm343 h5
April26°C154 mm345 h5
May27°C158 mm349 h7
June28°C126 mm338 h10
July28°C89 mm351 h9
August28°C146 mm353 h7
September28°C107 mm330 h5
October28°C148 mm327 h5
November26°C257 mm278 h4
December26°C151 mm305 h4

About 3,946 hours of sun a year. Roughly 160 rainy days a year.

These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.