Weather in San Juan, Puerto Rico
Flowers spill across the islands. Day 59 of spring. Read this microseason across nine climate regions →
- TodayMay 16Drizzle85%91°76°
- SundayMay 17Drizzle78%88°77°
- MondayMay 18Light Drizzle65%89°76°
- TuesdayMay 19Light Drizzle42%89°74°
- WednesdayMay 20Heavy Drizzle74%83°74°
- ThursdayMay 21Light Drizzle56%88°74°
- FridayMay 22Light Drizzle71%89°74°
- PM 2.5
- 9.3 μg/m³
- PM 10
- 17.6 μg/m³
- NO₂
- 0.8 μg/m³
- Ozone
- 47.0 μg/m³
- UV Index
- 0.0 Low
When the dew is on the grass, rain will never come to pass.
- Moonrise
- 10:12 AM
- Moonset
- —
- In sign
- ♊︎ Gemini
Flowers spill across the islands
San Juan at a glance
- Today vs. normal: 14°F below the seasonal normal for this latitude
- Last frost: December 7 (climatological average for this latitude)
- Microseason: 28 of 72, May 16–20
- Planting window: Direct sow okra, melons, and southern peas. Thin carrot rows.
Right now in the garden
Peak growing season
As of May 17, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | lettuce, peas, spinach, radishes | — |
| March | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | — |
| April | tomatoes, peppers, beans, squash | — |
| May | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | — | lettuce, peas, radishes |
| July | — | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | — | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | fall brassicas, garlic (overwinter), carrots | — |
| December | — | — |
A year in weather
August brings San Juan's warmest temperatures (~85°F mean) while January delivers the coldest (~69°F). September sees peak rainfall at 8.2 inches, and February records the driest conditions at 2.0 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 69° | 2.1″ | 7 |
| February | 71° | 2.0″ | 7 |
| March | 73° | 2.2″ | 7 |
| April | 77° | 3.3″ | 11 |
| May | 80° | 4.8″ | 16 |
| June | 83° | 7.9″ | 25 |
| July | 84° | 5.8″ | 19 |
| August | 85° | 6.9″ | 23 |
| September | 83° | 8.2″ | 25 |
| October | 81° | 7.9″ | 25 |
| November | 76° | 3.3″ | 11 |
| December | 72° | 2.5″ | 8 |
Regional context
San Juan belongs to a varied climate region — part of a cohort sharing similar temperature ranges, seasonal patterns, and growing conditions with nearby cities.
Similar climates: Aguadilla, PR, Bayamón, PR, Carolina, PR, Arecibo, PR, Ponce, PR.
Naturalist notes
May brings the peak flowering period for flamboyant trees, their orange-red blooms creating canopies of color across the city.
Trade winds carry migrating warblers northward during late April and early May, as these small birds follow ancient flyways toward North American breeding grounds.
Frequently asked
- When does it freeze in San Juan?
- San Juan's last spring frost typically occurs around mid-February, while the first fall frost arrives around mid-December.
- What is the rainy season in San Juan?
- September records the highest rainfall with about 8.2 inches on average; the city receives roughly 57 inches annually.
- What is the warmest month in San Juan?
- August typically brings the warmest weather, averaging about 85°F.
- What is the coldest month in San Juan?
- January typically delivers the coldest temperatures, averaging about 69°F.
- When can I start a vegetable garden in San Juan?
- Cool-season crops (peas, lettuce) can be planted around the last spring frost (mid-February); warm-season crops (tomatoes, peppers) should wait until 1–2 weeks after.
- How many rainy days does San Juan get?
- San Juan records about 184 rainy days per year on average.
- What hardiness zone is San Juan?
- San Juan's USDA hardiness zone depends on its lowest average winter temperature; check the USDA's online lookup with the city ZIP for the current zone designation.
Climate
San Juan, Puerto Rico experiences a varied climate zone. Temperatures hover near 69°F during January while July averages 84°F — creating a 15°F seasonal swing.
Throughout the year, San Juan receives about 57 inches of precipitation distributed across roughly 184 rainy days.
Latitude (18.4°N), proximity to large water bodies, and elevation determine the rhythm of the year — shaping what grows here, when frost occurs, and the daily weather patterns.