San Bernardino in Summer
In summer (December, January and February), San Bernardino sees average daytime highs around 32°C and overnight lows near 23°C, with 429 mm of rain over about 38 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 32°C. The sky is clear or mostly clear about 41% of the time across summer, and the air most often feels oppressive.
Summer is San Bernardino's weakest season of the year to visit on our travel score. For the whole year in context, see San Bernardino's year-round climate.
- Avg daytime high
- 32°C
- warmest season of the year
- Avg overnight low
- 23°C
- Rainfall
- 429 mm
- 38 wet days
- Avg wind
- 11 km/h
- Travel score
- 3.7
- weakest season of the year
- Months
- Dec · Jan · Feb
Temperature in San Bernardino in Summer
Across summer, daytime highs hold fairly steady around 32°C.
A typical summer day in San Bernardino reaches about 32°C and drops to 23°C overnight. The warmest of the three months is January, the coolest December.
How summer really feels in San Bernardino
Once humidity and wind are folded in, summer brings about 90 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 Bernardino weather by month
How the three summer months (December, January and February) 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 | 33° / 23° | 124 | 12.9 | 13.4 | 3.5 |
| Feb | 32° / 23° | 142 | 12.3 | 12.9 | 3.7 |
| Mar | 31° / 22° | 109 | 10.3 | 12.2 | 4.6 |
| Apr | 28° / 19° | 142 | 8.9 | 11.4 | 6.2 |
| May | 24° / 16° | 130 | 8.8 | 10.8 | 7.2 |
| Jun | 23° / 14° | 97 | 8.3 | 10.5 | 7.1 |
| Jul | 23° / 13° | 82 | 7.7 | 10.6 | 7.4 |
| Aug | 26° / 15° | 70 | 6.6 | 11.1 | 7.7 |
| Sep | 27° / 16° | 113 | 8.6 | 11.8 | 6.9 |
| Oct | 29° / 19° | 196 | 12.1 | 12.6 | 5.3 |
| Nov | 30° / 20° | 177 | 11.1 | 13.2 | 4.8 |
| Dec | 32° / 22° | 163 | 12.7 | 13.5 | 3.9 |
Cloud cover in Summer
The sky is clear or mostly clear about 41% of the time across summer.
Chance of precipitation in Summer
San Bernardino gets around 429 mm of rain over 38 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 11 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 13 h 30 min in early December to 12 h 36 min by late February. 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 6.4 kWh/m².
Is summer a good time to visit San Bernardino?
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 weaker month for outdoor sightseeing in San Bernardino. The water and warmth also suit a beach or pool day.
What to pack for San Bernardino in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, San Bernardino sees daytime highs around 32°C and nights near 23°C. Pack light clothes and sun protection. Worth having: rain gear. About 38 days see rain.
UV index in San Bernardino in Summer
Clear-sky midday UV across summer averages around 14 (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 Bernardino peaks around January 17 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 15 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) | 15 | 14 | 11 | 9 | 6 | 5 | 5 | 5 | 8 | 8 | 12 | 13 |
| Level | Extreme | Extreme | Extreme | Very high | High | Moderate | Moderate | High | Very high | Very high | Extreme | Extreme |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 15 | Extreme |
| Feb | 14 | Extreme |
| Mar | 11 | Extreme |
| Apr | 9 | Very high |
| May | 6 | High |
| Jun | 5 | Moderate |
| Jul | 5 | Moderate |
| Aug | 5 | High |
| Sep | 8 | Very high |
| Oct | 8 | Very high |
| Nov | 12 | Extreme |
| Dec | 13 | Extreme |
Air quality in San Bernardino 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 Bernardino is worst in September — around 28 µg/m³ PM2.5 (moderate), about 2.9× the cleanest month (December, 10 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) | 11 | 12 | 11 | 13 | 13 | 15 | 17 | 25 | 28 | 18 | 13 | 10 |
| Level | Good | Moderate | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 11 | Good |
| Feb | 12 | Moderate |
| Mar | 11 | Good |
| Apr | 13 | Moderate |
| May | 13 | Moderate |
| Jun | 15 | Moderate |
| Jul | 17 | Moderate |
| Aug | 25 | Moderate |
| Sep | 28 | Moderate |
| Oct | 18 | Moderate |
| Nov | 13 | Moderate |
| Dec | 10 | Good |
Where is San Bernardino?
San Bernardino sits at 25.3°S, 57.3°W, 0 m above sea level, in Paraguay. The nearest listed city is Areguá, 9.0 km away.
Topography around San Bernardino
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of San Bernardino.
Within 3 km, the terrain around San Bernardino has only modest variations in elevation — a maximum elevation change of 183 m around an average of 91 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 272 m; within 80 km, significant variations in elevation — a maximum elevation change of 529 m.
The land around San Bernardino is covered by trees (51%) and water (42%) within 3 km, trees (72%) within 16 km, and grassland (52%) and trees (39%) within 80 km.
Paraguay travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type A / B / C / N
- 220 V · 50 Hz
- Prices
- ≈ 35% of US
- price level, 2025
- GDP per capita
- $7,027
- 2025
- Happiness
- 6.2 / 10
- World Happiness, 2025
- Safe drinking water
- 64%
- of population, 2024
- Homicide rate
- 6.8
- per 100k, 2023
- Road deaths
- 22
- per 100k/yr, 2019
- Income group
- Upper middle
- World Bank
- English
- Moderate
- EF EPI 531
- 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 Bernardino (-25.3107°, -57.2963°, elevation 0 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.