San Juan in Fall
In fall (September, October and November), San Juan sees average daytime highs around 86°F and overnight lows near 67°F, with 7.2 in of rain over about 24 wet days across the season. It is the 3rd-warmest season and the wettest season of the year.
Over the season highs ease from about 95°F in early September to 77°F by late November. The sky is clear or mostly clear about 47% of the time across fall, and the air most often feels oppressive.
Fall is San Juan's 2nd-best season to visit on our travel score. For the whole year in context, see San Juan's year-round climate.
- Avg daytime high
- 86°F
- 3rd-warmest season
- Avg overnight low
- 67°F
- Rainfall
- 7.2 in
- 24 wet days
- Avg wind
- 9 mph
- Travel score
- 5.3
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in San Juan in Fall
Over the season highs ease from about 95°F in early September to 77°F by late November.
A typical fall day in San Juan reaches about 86°F and drops to 67°F overnight. The warmest of the three months is September, the coolest November.
How fall really feels in San Juan
Once humidity and wind are folded in, fall brings about 45 days that feel above 90°F and 0 that feel at or below 32°F.
The story in fall is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
San Juan weather by month
How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 72° / 52° | 1.0 | 4.4 | 10.5 | 7.5 |
| Feb | 76° / 56° | 0.9 | 4.4 | 11.1 | 7.7 |
| Mar | 82° / 62° | 1.4 | 5.2 | 11.8 | 6.8 |
| Apr | 88° / 68° | 1.7 | 5.3 | 12.6 | 5.0 |
| May | 92° / 73° | 2.2 | 6.6 | 13.3 | 3.5 |
| Jun | 96° / 77° | 2.0 | 7.1 | 13.6 | 2.4 |
| Jul | 98° / 78° | 2.1 | 5.8 | 13.5 | 2.0 |
| Aug | 98° / 78° | 1.6 | 6.8 | 12.9 | 1.8 |
| Sep | 93° / 75° | 3.5 | 11.8 | 12.2 | 3.1 |
| Oct | 87° / 68° | 2.3 | 6.7 | 11.4 | 5.2 |
| Nov | 79° / 60° | 1.4 | 5.3 | 10.7 | 7.5 |
| Dec | 73° / 54° | 1.2 | 5.1 | 10.4 | 7.6 |
Cloud cover in Fall
The sky is clear or mostly clear about 47% of the time across fall.
Chance of precipitation in Fall
San Juan gets around 7.2 in of rain over 24 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Fall
Winds average 9 mph across fall.
Sunrise & sunset in Fall
Daylight runs from about 12 h 30 min in early September to 10 h 30 min by late November. The lit band spans sunrise to sunset each day.
Solar energy in Fall
Average shortwave solar energy reaching the ground each day across fall, about 4.5 kWh/m².
Is fall a good time to visit San Juan?
Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
fall is a reasonable time to visit San Juan for sightseeing. The water and warmth also suit a beach or pool day.
What to pack for San Juan in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, San Juan sees daytime highs around 86°F and nights near 67°F. Pack light clothes. Worth having: rain gear and sun protection. About 24 days see rain.
UV index in San Juan in Fall
Clear-sky midday UV across fall averages around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in San Juan peaks around June 21 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 5 (moderate).
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) | 5 | 7 | 8 | 11 | 9 | 12 | 11 | 11 | 10 | 8 | 6 | 5 |
| Level | Moderate | High | Very high | Extreme | Very high | Extreme | Extreme | Extreme | Very high | Very high | High | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 5 | Moderate |
| Feb | 7 | High |
| Mar | 8 | Very high |
| Apr | 11 | Extreme |
| May | 9 | Very high |
| Jun | 12 | Extreme |
| Jul | 11 | Extreme |
| Aug | 11 | Extreme |
| Sep | 10 | Very high |
| Oct | 8 | Very high |
| Nov | 6 | High |
| Dec | 5 | Moderate |
Air quality in San Juan in Fall
Average fine-particle pollution (PM2.5) through the year — so you can see where fall falls, not just the annual average.
Air quality in San Juan is worst in July — around 26 µg/m³ PM2.5 (moderate), about 3.5× the cleanest month (November, 7 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) | 9 | 10 | 11 | 13 | 20 | 21 | 26 | 19 | 12 | 8 | 7 | 9 |
| Level | Good | Good | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 9 | Good |
| Feb | 10 | Good |
| Mar | 11 | Good |
| Apr | 13 | Moderate |
| May | 20 | Moderate |
| Jun | 21 | Moderate |
| Jul | 26 | Moderate |
| Aug | 19 | Moderate |
| Sep | 12 | Moderate |
| Oct | 8 | Good |
| Nov | 7 | Good |
| Dec | 9 | Good |
Where is San Juan?
San Juan sits at 26.2°N, 98.2°W, 108 ft above sea level, in United States. The nearest listed city is Pharr, 1.9 mi away.
Topography around San Juan
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of San Juan.
Within 2 miles, the terrain around San Juan has only modest variations in elevation — a maximum elevation change of 52 ft around an average of 108 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 167 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,027 ft.
The land around San Juan is covered by artificial surfaces (49%) and trees (24%) within 2 miles, cropland (31%), artificial surfaces (25%) and trees (22%) within 10 miles, and cropland (38%) and grassland (24%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- 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 (26.1892°, -98.1553°, elevation 108 ft), 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.