San Juan in Summer
In summer (June, July and August), San Juan sees average daytime highs around 30°C and overnight lows near 25°C, with 242 mm of rain over about 49 wet days across the season. It is the warmest season of the year and the 2nd-wettest season.
Across summer, daytime highs hold fairly steady around 30°C. The sky is clear or mostly clear about 33% of the time across summer, and the air most often feels oppressive.
Summer is San Juan's 3rd-best season to visit on our travel score. San Juan has little temperature swing across the year, so its calendar seasons blur — the season framing matters less here than for a place with four distinct seasons. For the whole year in context, see San Juan's year-round climate.
- Avg daytime high
- 30°C
- warmest season of the year
- Avg overnight low
- 25°C
- Rainfall
- 242 mm
- 49 wet days
- Avg wind
- 16 km/h
- Travel score
- 4.3
- 3rd-best season
- Months
- Jun · Jul · Aug
Temperature in San Juan in Summer
Across summer, daytime highs hold fairly steady around 30°C.
A typical summer day in San Juan reaches about 30°C and drops to 25°C overnight. The warmest of the three months is August, the coolest June.
How summer really feels in San Juan
Once humidity and wind are folded in, summer brings about 92 days that feel above 32°C and 0 that feel at or below 0°C.
The story in summer is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
San Juan weather by month
How the three summer months (June, July and August) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 27° / 23° | 39 | 10.4 | 11 | 6.8 |
| Feb | 27° / 22° | 28 | 7.6 | 11.4 | 7.1 |
| Mar | 28° / 23° | 39 | 8.4 | 11.9 | 6.9 |
| Apr | 28° / 23° | 72 | 11 | 12.4 | 5.8 |
| May | 29° / 24° | 112 | 16.2 | 12.9 | 4.7 |
| Jun | 30° / 25° | 68 | 13.9 | 13.1 | 4.5 |
| Jul | 30° / 25° | 80 | 16.5 | 13 | 4.4 |
| Aug | 30° / 25° | 95 | 18.7 | 12.6 | 4.0 |
| Sep | 30° / 25° | 131 | 20.8 | 12.1 | 3.7 |
| Oct | 29° / 25° | 125 | 20.5 | 11.6 | 4.0 |
| Nov | 28° / 24° | 112 | 18.2 | 11.1 | 4.9 |
| Dec | 27° / 23° | 48 | 12.2 | 10.9 | 6.4 |
Cloud cover in Summer
The sky is clear or mostly clear about 33% of the time across summer.
Chance of precipitation in Summer
San Juan gets around 242 mm of rain over 49 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 16 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 13 hours in early June to 12 h 24 min by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 6.5 kWh/m².
Hazard calendar for San Juan
In summer, San Juan overlaps its atlantic hurricane and dust season. The full year is below, with each hazard's peak months called out.
San Juan sits in the Atlantic hurricane belt; the season peaks August–October.
San Juan sees seasonal dust haze (July), heaviest in July.
Is summer a good time to visit San Juan?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a reasonable time to visit San Juan for sightseeing.
What to pack for San Juan in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, San Juan sees daytime highs around 30°C and nights near 25°C. Pack light clothes, rain gear and sun protection. About 49 days see rain.
Sea temperature near San Juan in Summer
The nearest coast averages about 28°C across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 18 km away) is warmest in September at about 29°C and coldest in February near 26°C.
The water stays above 20°C all year — warm enough for a swim any month.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 27 | 26 | 26 | 27 | 27 | 28 | 28 | 29 | 29 | 29 | 28 | 27 |
| Comfort | Warm | Warm | Warm | Warm | Warm | Warm | Tropical | Tropical | Tropical | Tropical | Tropical | Warm |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 27 | Warm |
| Feb | 26 | Warm |
| Mar | 26 | Warm |
| Apr | 27 | Warm |
| May | 27 | Warm |
| Jun | 28 | Warm |
| Jul | 28 | Tropical |
| Aug | 29 | Tropical |
| Sep | 29 | Tropical |
| Oct | 29 | Tropical |
| Nov | 28 | Tropical |
| Dec | 27 | Warm |
UV index in San Juan in Summer
Clear-sky midday UV across summer averages around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in San Juan peaks around April 13 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 7 (high).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 8 | 10 | 12 | 13 | 11 | 12 | 12 | 12 | 12 | 10 | 8 | 7 |
| Level | Very high | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Very high | Very high | High |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 8 | Very high |
| Feb | 10 | Extreme |
| Mar | 12 | Extreme |
| Apr | 13 | Extreme |
| May | 11 | Extreme |
| Jun | 12 | Extreme |
| Jul | 12 | Extreme |
| Aug | 12 | Extreme |
| Sep | 12 | Extreme |
| Oct | 10 | Very high |
| Nov | 8 | Very high |
| Dec | 7 | High |
Air quality in San Juan in Summer
Average fine-particle pollution (PM2.5) through the year — so you can see where summer falls, not just the annual average.
Air quality in San Juan is worst in July — around 24 µg/m³ PM2.5 (moderate), about 4.6× the cleanest month (January, 5 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 5 | 7 | 7 | 8 | 14 | 23 | 24 | 20 | 15 | 15 | 8 | 5 |
| Level | Good | Good | Good | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 5 | Good |
| Feb | 7 | Good |
| Mar | 7 | Good |
| Apr | 8 | Good |
| May | 14 | Moderate |
| Jun | 23 | Moderate |
| Jul | 24 | Moderate |
| Aug | 20 | Moderate |
| Sep | 15 | Moderate |
| Oct | 15 | Moderate |
| Nov | 8 | Good |
| Dec | 5 | Good |
Where is San Juan?
San Juan sits at 18.5°N, 66.1°W, 7 m above sea level, in Puerto Rico. The nearest listed city is Cataño, 3.0 km away.
Topography around San Juan
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of San Juan.
Within 3 km, the terrain around San Juan has only modest variations in elevation — a maximum elevation change of 42 m around an average of 2 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 289 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,308 m.
The land around San Juan is covered by water (81%) within 3 km, water (56%) and artificial surfaces (24%) within 16 km, and water (58%) and trees (32%) within 80 km.
Puerto Rico travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 78% of US
- price level, 2025
- GDP per capita
- $40,620
- 2025
- Happiness
- 7.0 / 10
- World Happiness, 2015
- Safe drinking water
- 99%
- of population, 2024
- Homicide rate
- 14.6
- per 100k, 2023
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for San Juan (18.4663°, -66.1057°, elevation 7 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.