San Justo in Summer
In summer (December, January and February), San Justo sees average daytime highs around 28°C and overnight lows near 18°C, with 264 mm of rain over about 24 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 28°C. The sky is clear or mostly clear about 52% of the time across summer, and the air most often feels muggy.
Summer is San Justo's 3rd-best season to visit on our travel score. For the whole year in context, see San Justo's year-round climate.
- Avg daytime high
- 28°C
- warmest season of the year
- Avg overnight low
- 18°C
- Rainfall
- 264 mm
- 24 wet days
- Avg wind
- 13 km/h
- Travel score
- 6.6
- 3rd-best season
- Months
- Dec · Jan · Feb
Temperature in San Justo in Summer
Across summer, daytime highs hold fairly steady around 28°C.
A typical summer day in San Justo reaches about 28°C and drops to 18°C overnight. The warmest of the three months is January, the coolest December.
San Justo 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 | 29° / 19° | 87 | 7.4 | 14.1 | 6.3 |
| Feb | 28° / 18° | 92 | 8.2 | 13.3 | 6.8 |
| Mar | 26° / 17° | 85 | 7.4 | 12.3 | 7.4 |
| Apr | 22° / 13° | 91 | 7.9 | 11.2 | 7.2 |
| May | 18° / 10° | 61 | 6.1 | 10.2 | 6.4 |
| Jun | 15° / 7° | 60 | 5.9 | 9.7 | 5.0 |
| Jul | 14° / 6° | 60 | 6.1 | 9.9 | 4.6 |
| Aug | 16° / 8° | 62 | 5.8 | 10.7 | 5.7 |
| Sep | 18° / 9° | 72 | 6.7 | 11.8 | 6.4 |
| Oct | 21° / 12° | 109 | 9.1 | 12.9 | 6.7 |
| Nov | 24° / 15° | 93 | 8.4 | 13.8 | 7.3 |
| Dec | 27° / 17° | 85 | 8.6 | 14.3 | 6.8 |
Cloud cover in Summer
The sky is clear or mostly clear about 52% of the time across summer.
Chance of precipitation in Summer
San Justo gets around 264 mm of rain over 24 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 13 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 14 h 12 min in early December to 12 h 54 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 7.0 kWh/m².
Is summer a good time to visit San Justo?
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 Justo for sightseeing. The water and warmth also suit a beach or pool day.
What to pack for San Justo in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, San Justo sees daytime highs around 28°C and nights near 18°C. Pack light clothes and sun protection. Worth having: rain gear. About 24 days see rain.
Sea temperature near San Justo in Summer
The nearest coast averages about 24°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 January at about 25°C and coldest in July near 13°C.
It's comfortable for a long swim from Nov 9 to Apr 20 — about 5.4 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 25 | 25 | 23 | 21 | 17 | 14 | 13 | 13 | 15 | 18 | 21 | 23 |
| Comfort | Warm | Warm | Refreshing | Refreshing | Cool | Bracing | Bracing | Bracing | Cool | Cool | Refreshing | Refreshing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 25 | Warm |
| Feb | 25 | Warm |
| Mar | 23 | Refreshing |
| Apr | 21 | Refreshing |
| May | 17 | Cool |
| Jun | 14 | Bracing |
| Jul | 13 | Bracing |
| Aug | 13 | Bracing |
| Sep | 15 | Cool |
| Oct | 18 | Cool |
| Nov | 21 | Refreshing |
| Dec | 23 | Refreshing |
UV index in San Justo 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 Justo peaks around January 14 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 19 at about 3 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 13 | 11 | 10 | 6 | 3 | 3 | 3 | 4 | 6 | 8 | 11 | 12 |
| Level | Extreme | Extreme | Very high | High | Moderate | Moderate | Moderate | Moderate | High | Very high | Extreme | Extreme |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 13 | Extreme |
| Feb | 11 | Extreme |
| Mar | 10 | Very high |
| Apr | 6 | High |
| May | 3 | Moderate |
| Jun | 3 | Moderate |
| Jul | 3 | Moderate |
| Aug | 4 | Moderate |
| Sep | 6 | High |
| Oct | 8 | Very high |
| Nov | 11 | Extreme |
| Dec | 12 | Extreme |
Air quality in San Justo 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 Justo is worst in June — around 25 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (December, 12 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) | 13 | 14 | 16 | 17 | 22 | 25 | 25 | 24 | 19 | 16 | 13 | 12 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 13 | Moderate |
| Feb | 14 | Moderate |
| Mar | 16 | Moderate |
| Apr | 17 | Moderate |
| May | 22 | Moderate |
| Jun | 25 | Moderate |
| Jul | 25 | Moderate |
| Aug | 24 | Moderate |
| Sep | 19 | Moderate |
| Oct | 16 | Moderate |
| Nov | 13 | Moderate |
| Dec | 12 | Moderate |
Where is San Justo?
San Justo sits at 34.7°S, 58.6°W, 29 m above sea level, in Argentina. The nearest listed city is Isidro Casanova, 3.0 km away.
Topography around San Justo
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of San Justo.
Within 3 km, the terrain around San Justo has only modest variations in elevation — a maximum elevation change of 28 m around an average of 28 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 53 m; within 80 km, only modest variations in elevation — a maximum elevation change of 138 m.
The land around San Justo is covered by artificial surfaces (89%) within 3 km, artificial surfaces (70%) within 16 km, and grassland (31%), cropland (24%) and water (20%) within 80 km.
Argentina travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type C / I
- 220 V · 50 Hz
- Prices
- ≈ 46% of US
- price level, 2025
- GDP per capita
- $14,898
- 2025
- Happiness
- 6.4 / 10
- World Happiness, 2025
- Homicide rate
- 4.5
- per 100k, 2023
- Road deaths
- 14.1
- per 100k/yr, 2019
- Income group
- Upper middle
- World Bank
- English
- High
- EF EPI 575
- 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 Justo (-34.6811°, -58.5638°, elevation 29 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.