San Juan, Puerto Rico Climate & Monthly Averages
The climate of San Juan
San Juan has one of the steadier climates in our dataset. Average highs move only 3°C across the whole year - from 83°F (28°C) in January to 88°F (31°C) in July - so the practical difference between seasons here is rainfall and daylight, not warmth.
Climate quick facts
- Hottest month: July - highs near 88°F (31°C)
- Coldest month: January - highs near 83°F (28°C)
- Decade extremes (2015-2024): 97°F (36°C) high · 65°F (18°C) low
- Wettest month: September (22 rainy days) · Sunniest: June (12.2 h sun/day)
- Climate type: tropical wet-and-dry
- Annual swing: 3°C between the average warmest and coolest month · day to night: 6°C
- Months averaging 30°C or hotter: 6
- Average humidity: 77%
Temperatures through the year
Days and nights are about 6°C apart on average - narrower than about 89% of the cities we track. January is the coolest month, with highs of 83°F (28°C) and lows near 71°F (22°C). At its warmest, in July, San Juan runs to 88°F (31°C) in the afternoon and back to 77°F (25°C) by dawn. Across the gridded 2015-2024 daily record, the highest daily maximum for this location was 97°F (36°C) and the lowest daily minimum 65°F (18°C). Average highs hold at or above 30°C for 6 months of the year, May through October being the unbroken run.
Rain, sun and snow
June is the brightest month at 12.2 hours of sun a day, against an annual average of 11.1 - sunnier than 97% of the 3496 cities in our dataset. Between the average July and the average January lie 3°C, a narrower spread than all but 9% of the 3496 cities in our dataset. Precipitation concentrates in September - 6.1 inches (155 mm) on 22 days - and thins out by January.
How San Juan compares
- Rain or snow reaches the ground on 214 days a year - more wet days than 92% of the 3496 cities we track.
- San Juan averages 80°F (26°C) across the year - warmer than 91% of the 3496 cities we track.
Ranked against every city in our dataset, each measured on the same ten-year window.
Monthly climate table
| Month | High | Low | Rain days | Precipitation | Sunshine | Daylight | Wet-day chance | Humidity |
|---|---|---|---|---|---|---|---|---|
| January | 83° | 71° | 14 | 2.1 in | 10.8 h/day | 11.1 h | 45% | 77% |
| February | 83° | 72° | 15 | 2.4 in | 10.8 h/day | 11.5 h | 53% | 75% |
| March | 84° | 72° | 15 | 2.2 in | 11.1 h/day | 12.0 h | 48% | 73% |
| April | 85° | 73° | 16 | 3.1 in | 11.7 h/day | 12.5 h | 55% | 74% |
| May | 87° | 75° | 17 | 3.1 in | 11.9 h/day | 13.0 h | 56% | 75% |
| June | 89° | 76° | 17 | 2.4 in | 12.2 h/day | 13.2 h | 55% | 75% |
| July | 88° | 77° | 19 | 3.1 in | 12.0 h/day | 13.1 h | 63% | 76% |
| August | 88° | 77° | 19 | 3.6 in | 11.5 h/day | 12.7 h | 63% | 78% |
| September | 88° | 77° | 22 | 6.1 in | 10.8 h/day | 12.2 h | 74% | 81% |
| October | 87° | 76° | 22 | 4.9 in | 10.3 h/day | 11.7 h | 70% | 82% |
| November | 85° | 74° | 20 | 5.3 in | 9.7 h/day | 11.2 h | 66% | 82% |
| December | 83° | 73° | 18 | 2.4 in | 10.6 h/day | 11.0 h | 56% | 79% |
San Juan month by month
Average high and low for each month, with the bar showing where it sits in San Juan's year (left is the coldest night, right is the warmest afternoon).
January
- Rain
- 14 days
- Sunshine
- 10.8 h
- Daylight
- 11.1 h
February
- Rain
- 15 days
- Sunshine
- 10.8 h
- Daylight
- 11.5 h
March
- Rain
- 15 days
- Sunshine
- 11.1 h
- Daylight
- 12.0 h
April
- Rain
- 16 days
- Sunshine
- 11.7 h
- Daylight
- 12.5 h
May
- Rain
- 17 days
- Sunshine
- 11.9 h
- Daylight
- 13.0 h
June
- Rain
- 17 days
- Sunshine
- 12.2 h
- Daylight
- 13.2 h
July
- Rain
- 19 days
- Sunshine
- 12.0 h
- Daylight
- 13.1 h
August
- Rain
- 19 days
- Sunshine
- 11.5 h
- Daylight
- 12.7 h
September
- Rain
- 22 days
- Sunshine
- 10.8 h
- Daylight
- 12.2 h
October
- Rain
- 22 days
- Sunshine
- 10.3 h
- Daylight
- 11.7 h
November
- Rain
- 20 days
- Sunshine
- 9.7 h
- Daylight
- 11.2 h
December
- Rain
- 18 days
- Sunshine
- 10.6 h
- Daylight
- 11.0 h
Warmer places to go, by month: January · February · March · April · May · June · July · August · September · October · November · December
Seasons in San Juan
March through May
March through May brings hot afternoons here - highs near 86°F (30°C), nights near 73°F (23°C), and rain falls on around 49 of the 90 days. Daylight is generous - around 11.6 hours of sun a day. With the moisture factored in, afternoons feel hotter than the reading suggests - the humidity and dew point converter shows why.
June through August
June through August in San Juan is hot, with daytime highs averaging 88°F (31°C) and nights around 77°F (25°C); rain falls on around 55 of the 90 days. Daylight is generous - around 11.9 hours of sun a day.
September through November
September through November in San Juan sits firmly in the heat, with daytime highs averaging 86°F (30°C) and nights around 76°F (24°C); rain falls on around 64 of the 90 days. Daylight is generous - around 10.3 hours of sun a day.
December through February
Through December through February, San Juan runs hot: 83°F (28°C) by day, 72°F (22°C) after dark, and rain falls on around 47 of the 90 days. Daylight is generous - around 10.7 hours of sun a day.
Climate questions, answered
Is San Juan humid?
What is the average temperature in San Juan?
How much do temperatures drop at night in San Juan?
How often does it rain in San Juan?
Best time to visit San Juan
December to March is the sweet spot for San Juan - humidity and rainfall are at their lowest, which is what actually varies here. Expect 83°F (28°C) in the afternoon and around 15 days of rain in a typical month of it. For the same question asked the other way round, see where else is warm in December.
Pack for San Juan with light clothing for the warm months, proper waterproofs rather than an umbrella - wet days are the norm here and moisture-wicking fabrics for the humidity. Even in July, lows of 77°F (25°C) make an extra layer worth the space.
San Juan temperature records (2015-2024)
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need the precipitation in other units? The mm-to-inches rainfall converter handles it.