How extreme does San Juan's weather get?

The hottest, coldest, wettest and snowiest days San Juan has recorded — the outer limits of what its weather can do, and how far they sit beyond a normal day.

Based on 34 years of daily weather observations (1991–present), from the San Juan station 11 km away. Updated through August 2025 — an all-time extreme only changes when a more extreme day actually occurs, so some dates are old. That is normal, not stale data.

The four kinds of extreme

The hottest, coldest, wettest and snowiest single days San Juan has recorded — each shown against what a normal day that time of year looks like.

🔥 Hottest day

115°F Dec 17, 2023

That is about 19°F hotter than a normal December afternoon in San Juan (typical high near 95°F).

The three most extreme on record

1 115°F Dec 17, 2023recent

2 114°F Dec 20, 1995

3 114°F Jan 31, 2003

❄️ Coldest night

16°F Jul 4, 2011

About 16°F colder than a normal July night in San Juan (typical low near 31°F).

The three most extreme on record

1 16°F Jul 4, 2011

2 17°F Jul 22, 2013

3 18°F Jul 30, 1993

🌧️ Most rain in one day

7.83 in Mar 10, 1998

More rain in a single day than San Juan usually gets in the whole month of March (typical March total about 1.2 in).

The three most extreme on record

1 7.83 in Mar 10, 1998

2 7.24 in Dec 2, 2019

3 7.20 in Dec 29, 2014

How hot and cold it gets, month by month

The shaded band is the normal range of daily temperatures for each month. The dots show the most extreme it has ever been — so you can see how far beyond a normal day the records really sit.

normal range of daily temperatureshottest ever recordedcoldest ever recorded

San Juan's record heat sits well above even a hot day for the season — December's 115°F is about 19°F beyond a normal hot afternoon. Its record cold is just as far below a normal winter night — the dots mark how rare each extreme really is.

In plain terms

In a normal year, San Juan's warmest days reach the high 90s°F and its coldest nights drop to the low 30s°F. But across the record it has gone as high as 115°F and as low as 16°F. A single day has delivered over 8 inches of rain. Those are the outer edges worth knowing if you are moving here, planning a trip, or thinking about a house.

Methodology & sources

Temperature & precipitation — the official 1991–2020 climate normals from the WMO's CLINO 1991–2020 collection, measured at San_juan_aero, about 11 km from the city centre.

How we build these numbers →

← San Juan city detail