San Juan, Puerto Rico Weather
Storm intensity ebbs slightly. Day 93 of summer. Read this microseason across nine climate regions →
San Juan weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 10:19 AM AST · Open-Meteo
- TodaySep 21Drizzle later67%0.10″91°77°—
- TuesdaySep 22Mostly Clear82%0.07″89°77°-2°
- WednesdaySep 23Drizzle64%0.09″91°76°+2°
- ThursdaySep 24Drizzle80%0.04″90°75°-1°
- FridaySep 25Light Drizzle68%0.02″92°77°+2°
- SaturdaySep 26Light Drizzle58%0.01″93°77°+1°
- SundaySep 27Light Drizzle67%0.05″91°78°-2°
Air quality now AQI 20 · Good
AQI 20 (Good), driven by Ozone. AQI flat over the last 6 hours (within ±3 points).
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
September dries up ditches or breaks down bridges.
- Moonrise
- 3:05 PM
- Moonset
- 1:37 AM
- In sign
- ♑︎ Capricorn
Storm intensity ebbs slightly
Read this microseason across nine climate regions →
All 72 microseasons on the year wheel →
San Juan at a glance
- Today vs. normal: Today averages 84°F (high 91°F, low 77°F), about the 83°F normal for Sep 21
- Last frost: None — no 32°F night in 1991–2020 (NOAA station 1 km away)
- Microseason: Sep 21–25
- Planting calendar: September — plant tomatoes, peppers, beans, squash; harvest summer squash, winter squash
16-Day Forecast — San Juan
- Mon91°77°67%
- Tue89°77°82%
- Wed91°76°64%
- Thu90°75°80%
- Fri92°77°68%
- Sat93°77°58%
- Sun91°78°67%
- Mon92°78°51%
- Tue93°79°62%
- Wed91°80°71%
- Thu90°79°68%
- Fri89°79°61%
- Sat89°77°61%
- Sun88°75°64%
- Mon92°76°59%
- Tue89°69°42%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near San Juan
Interactive wind and temperature map centered on San Juan — it loads in your browser. Open the full weather map.
Right now in the garden
Year-round growing
As of September 21, sowing here runs through the year. Freezes are uncommon, so there is no frost date to plan around; heat and rainfall set the calendar instead. This city's planting calendar for September: plant tomatoes, peppers, beans, and squash; harvest summer squash and winter squash.
Sun & seasons in San Juan
San Juan sits in San Juan County, where the year’s longest day runs 13h 14m of daylight and its shortest just 11h 1m — a swing of +2h 13m between the June and December solstices.
San Juan is the state’s largest city. The nearest town San Juan tracks is Carolina, roughly 5 miles to the E.
Air quality in San Juan
Air quality in San Juan’s county has trended cleaner since 2020; its cleanest year on record was 2021 (median AQI 7). See the full air-quality history for San Juan.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | tomatoes, peppers, beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| February | tomatoes, peppers, beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| March | tomatoes, peppers, beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| April | squash | tomatoes, peppers, beans, summer squash, winter squash |
| May | squash | tomatoes, peppers, beans, summer squash, winter squash |
| June | squash | tomatoes, summer squash, winter squash |
| July | squash | summer squash, winter squash |
| August | tomatoes, peppers, squash | summer squash, winter squash |
| September | tomatoes, peppers, beans, squash | summer squash, winter squash |
| October | tomatoes, peppers, beans, squash | summer squash, winter squash |
| November | tomatoes, peppers, beans, squash | beans, summer squash, winter squash |
| December | tomatoes, peppers, beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
A year in weather
San Juan's warmest month is August (~84°F mean) and its coldest is January (~78°F). Rainfall peaks in November (7.4 inches) and bottoms out in March (2.2 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 78° | 4.1″ | 18 |
| February | 78° | 2.6″ | 15 |
| March | 79° | 2.2″ | 13 |
| April | 80° | 4.6″ | 14 |
| May | 82° | 5.5″ | 17 |
| June | 83° | 4.7″ | 15 |
| July | 83° | 6.0″ | 19 |
| August | 84° | 6.3″ | 20 |
| September | 83° | 6.5″ | 18 |
| October | 83° | 5.2″ | 18 |
| November | 81° | 7.4″ | 21 |
| December | 79° | 4.8″ | 20 |
Regional context
Similar climates Caño Martin Peña, PR, Guaynabo, PR, Trujillo Alto, PR
Per NOAA NCEI 1991-2020 normals, San Juan runs from a 78°F January mean to 83°F in July, a 6°F seasonal spread, with near 59.9 inches of precipitation across about 208 wet days.
No season owns San Juan's rain: November reaches 7.4 inches across 20.6 days and March keeps 2.2 inches on 13.1, an even spread through San Juan's year. That even rhythm groups San Juan with places like Caño Martin Peña, PR, Guaynabo, PR and Trujillo Alto, PR.
Hard freezes are rare in San Juan: the coldest month averages 78°F, so San Juan's growing window runs most of the year. August is the hottest stretch near 84°F, pushing cool-season crops to the milder shoulder months. San Juan's open lawns chill fastest on clear nights.
Similar climates: Caño Martin Peña, PR, Guaynabo, PR, Trujillo Alto, PR, Carolina, PR, Cataño, PR.
Frequently asked
- When does it freeze in San Juan?
- San Juan essentially never freezes: the nearest NOAA station logged no 32°F night in any 1991–2020 year, and San Juan's coldest month averages 78°F.
- What is the rainy season in San Juan?
- Rainfall in San Juan peaks in November near 7.4 inches, out of about 60 inches annually.
- What is the warmest month in San Juan?
- The warmest stretch in San Juan comes in August, around 84°F on average.
- What is the coldest month in San Juan?
- On average January is the chilliest month in San Juan, about 78°F.
- When can I start a vegetable garden in San Juan?
- Any season works in San Juan: without a reliable freeze, San Juan's heat, not frost, decides when greens and tomatoes do best.
- How many rainy days does San Juan get?
- San Juan averages about 208 days with measurable rain or snow each year.
- What hardiness zone is San Juan?
- San Juan's hardiness zone tracks its winter low; with January near 78°F, check the USDA ZIP map for the exact zone.
- What is the 10-day forecast for San Juan?
- San Juan's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in San Juan?
- See this week's day-by-day rain chances for San Juan in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in San Juan?
- Current conditions for San Juan and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the San Juan forecast updated?
- The San Juan forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in San Juan?
- Today's sunrise and sunset times for San Juan are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for San Juan?
- The next few days in San Juan's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
ZIP codes in San Juan
- 00901
- 00906
- 00907
- 00908
- 00909
- 00910
- 00911
- 00912
- 00913
- 00915
- 00917
- 00918
- 00919
- 00920
- 00921
- 00922
- 00923
- 00924
- 00925
- 00926
- 00927
- 00928
- 00929
- 00931
- 00935
- 00936
- 00937
- 00939
- 00940
- 00955
- 00969
- 00975