San Juan climate
San Juan (Puerto Rico) has a tropical savanna (dry winter) climate (Köppen Aw). The average temperature over the year is 27 °C81 °F, and about 1,207 mm48 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
San Juan climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin |
|---|---|---|---|---|
| Jan | 2882 | 2374 | 2678 | 512.0 |
| Feb | 2882 | 2374 | 2678 | 451.8 |
| Mar | 2883 | 2374 | 2679 | 612.4 |
| Apr | 2985 | 2476 | 2780 | 773.0 |
| May | 2985 | 2577 | 2781 | 1295.1 |
| Jun | 3086 | 2679 | 2882 | 903.6 |
| Jul | 3086 | 2679 | 2883 | 1003.9 |
| Aug | 3087 | 2780 | 2883 | 1305.1 |
| Sep | 3086 | 2780 | 2883 | 1626.4 |
| Oct | 3085 | 2679 | 2882 | 1616.3 |
| Nov | 2983 | 2578 | 2781 | 1375.4 |
| Dec | 2882 | 2476 | 2679 | 642.5 |
| Year | 3087 | 2374 | 2781 | 1,20748 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 77% | 63% | 4.3 | 11:08 |
| Feb | 74% | 61% | 5.0 | 11:31 |
| Mar | 73% | 63% | 5.5 | 11:00 |
| Apr | 74% | 64% | 5.9 | 12:33 |
| May | 77% | 74% | 5.7 | 12:00 |
| Jun | 79% | 72% | 5.9 | 13:14 |
| Jul | 79% | 67% | 5.9 | 13:08 |
| Aug | 79% | 66% | 5.8 | 12:45 |
| Sep | 79% | 68% | 5.4 | 12:13 |
| Oct | 80% | 67% | 4.9 | 11:41 |
| Nov | 80% | 65% | 4.3 | 11:14 |
| Dec | 79% | 61% | 4.1 | 11:01 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of San Juan is like
The warmest month is August, with an average high of 30 °C87 °F and a low of 27 °C80 °F. The coldest is January, when highs average 28 °C82 °F and lows 23 °C74 °F. Temperatures barely change through the year: the warmest and the coolest month differ by only 3 °C5.4 °F.
It is wet, with about 1,207 mm48 in of precipitation per year. The wettest three-month stretch is September–November, which brings 38% of the annual total. The wettest month is September (162 mm6.4 in), the driest is February (45 mm1.8 in).
Relative humidity ranges from 73% in March to 80% in October. The clearest skies (lowest average cloud amount, 61%) are typical of December. Average wind speed near the ground ranges from 12 km/h (7 mph) in October to 16 km/h (10 mph) in July. Daylight lasts from about 11.0 hours in December to 13.2 hours in June.
Best time to visit San Juan
Based on these averages, the most comfortable months for sightseeing and outdoor activities are December–March: average highs of 28 °C82 °F to 28 °C83 °F with 45 mm1.8 in to 64 mm2.5 in of precipitation per month.
The most challenging month is September, which is hot, with average highs of 30 °C86 °F, very wet (162 mm6.4 in) and humid (79% relative humidity).
Comfort score: months are ranked by how close they come to an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for San Juan
- Wetter months (May, August–November) — highs 2983 to 30 °C87 °F, lows 2577 to 27 °C80 °F, about 144 mm5.7 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses and an umbrella or light rain jacket.
- Drier months (December–April, June and July) — highs 2882 to 30 °C86 °F, lows 2374 to 26 °C79 °F, about 70 mm2.7 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses.
How San Juan compares
Compared with Santo Domingo, about 399 km to the west, San Juan has practically the same average temperature and receives 108% more precipitation (1,207 mm48 in vs 581 mm23 in).
Of the 3 places in Puerto Rico covered by World Climates, San Juan is the 2nd warmest by annual mean temperature and the wettest by annual precipitation. See all of them on the Puerto Rico climate page.
Places in other countries with the most similar temperature and rainfall pattern: Roseau (Dominica, Am), Charlotte Amalie (U.S. Virgin Islands, Aw) and Saint Johns (Antigua and Barbuda, Aw).
The same NASA POWER grid cell also contains Bayamón (pop. 203,499). Their long-term averages in this dataset are essentially the same as for San Juan, so they do not have separate pages.
Nearby places
- Carolina 18 km · 27 °C81 °F · 1,207 mm48 in
- Ponce 75 km · 27 °C81 °F · 899 mm35 in
- Charlotte Amalie 125 km · 27 °C81 °F · 1,002 mm39 in
- Road Town 157 km · 27 °C81 °F · 646 mm25 in
- Punta Cana 243 km · 27 °C81 °F · 649 mm26 in
- La Romana 302 km · 28 °C82 °F · 609 mm24 in
- Marigot 322 km · 27 °C81 °F · 614 mm24 in
- San Pedro de Macorís 338 km · 27 °C81 °F · 605 mm24 in
Frequently asked questions
What is the warmest month in San Juan?
August is the warmest month in San Juan, with an average high of 30 °C (87 °F) and an average low of 27 °C (80 °F).
What is the coldest month in San Juan?
January is the coldest month, with an average high of 28 °C (82 °F) and an average low of 23 °C (74 °F).
When does it rain the most in San Juan?
September is the wettest month with about 162 mm (6.4 in) of precipitation; February is the driest with about 45 mm (1.8 in).
What is the best time to visit San Juan?
Judging by long-term averages, the most comfortable months are December–March.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.
The grid cell’s average elevation is 60 m, while San Juan lies at about 7 m. Temperatures on this page were therefore adjusted by +0.3 °C0.6 °F using the standard lapse rate of 6.5 °C per 1,000 m.