San Juan, Puerto Rico Climate & Monthly Averages
San Juan has a tropical wet-and-dry climate. July is the hottest month, averaging 88° by day; January is the coldest at 83°.
Rain, not cold, divides the year in 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.
The wet-and-dry rhythm at a glance
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.
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.
More climate facts for San Juan
- 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%
Choosing the right part of the year in San Juan
Choose dates by rain, not just temperature
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.
What the humidity changes
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.
Warm all year: the monthly rain pattern
Each card shows the average high and low. The bar places that month between San Juan's coldest night and 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
Looking for warmer alternatives? Browse warm places by month, or compare San Juan's coolest part of the year: January, February, December.
Monthly temperature and rain 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% |
How San Juan compares for rain and warmth
- 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.
These comparisons use the same ten-year window for every city in the dataset.
How the calendar changes in warm-weather 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.
Questions about heat and rain in San Juan
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What is the average temperature in San Juan?
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San Juan temperature extremes in the 2015–2024 dataset
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need another precipitation unit? Use the rainfall converter.