San Isidro in Summer
In summer (June, July and August), San Isidro sees average daytime highs around 24°C and overnight lows near 21°C, with 2475 mm of rain over about 92 wet days across the season. It is the 2nd-warmest season and the 2nd-wettest season.
Across summer, daytime highs hold fairly steady around 24°C. The sky is clear or mostly clear about 0% of the time across summer, and the air most often feels muggy.
Summer is San Isidro's weakest season of the year to visit on our travel score. San Isidro 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 Isidro's year-round climate.
- Avg daytime high
- 24°C
- 2nd-warmest season
- Avg overnight low
- 21°C
- Rainfall
- 2475 mm
- 92 wet days
- Avg wind
- 5 km/h
- Travel score
- 3.4
- weakest season of the year
- Months
- Jun · Jul · Aug
Temperature in San Isidro in Summer
Across summer, daytime highs hold fairly steady around 24°C.
A typical summer day in San Isidro reaches about 24°C and drops to 21°C overnight. The warmest of the three months is June, the coolest August.
San Isidro 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 | 24° / 20° | 210 | 25.2 | 11.5 | 4.8 |
| Feb | 24° / 20° | 140 | 21.6 | 11.7 | 5.1 |
| Mar | 25° / 21° | 138 | 25.6 | 11.9 | 4.7 |
| Apr | 25° / 21° | 330 | 28.6 | 12.2 | 3.8 |
| May | 24° / 21° | 730 | 30.8 | 12.4 | 3.4 |
| Jun | 24° / 21° | 709 | 29.9 | 12.5 | 3.4 |
| Jul | 24° / 21° | 833 | 31 | 12.5 | 3.4 |
| Aug | 24° / 21° | 933 | 31 | 12.3 | 3.4 |
| Sep | 24° / 21° | 808 | 30 | 12.1 | 3.4 |
| Oct | 24° / 20° | 952 | 30.8 | 11.8 | 3.4 |
| Nov | 24° / 20° | 924 | 29.9 | 11.6 | 3.5 |
| Dec | 24° / 20° | 413 | 28.8 | 11.5 | 4.1 |
Cloud cover in Summer
The sky is clear or mostly clear about 0% of the time across summer.
Chance of precipitation in Summer
San Isidro gets around 2475 mm of rain over 92 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 5 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 12 h 30 min in early June to 12 h 12 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 4.1 kWh/m².
Hazard calendar for San Isidro
In summer, San Isidro overlaps its rainy season season. The full year is below, with each hazard's peak months called out.
San Isidro's rainy season runs May–November, when most of the year's rain falls.
Is summer a good time to visit San Isidro?
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 Isidro.
What to pack for San Isidro in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, San Isidro sees daytime highs around 24°C and nights near 21°C. Pack rain gear. Worth having: light clothes. About 92 days see rain.
Sea temperature near San Isidro in Summer
The nearest coast averages about 29°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 28 km away) is warmest in March at about 30°C and coldest in November near 28°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) | 29 | 30 | 30 | 30 | 29 | 29 | 29 | 29 | 29 | 28 | 28 | 28 |
| Comfort | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Warm | Tropical |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 29 | Tropical |
| Feb | 30 | Tropical |
| Mar | 30 | Tropical |
| Apr | 30 | Tropical |
| May | 29 | Tropical |
| Jun | 29 | Tropical |
| Jul | 29 | Tropical |
| Aug | 29 | Tropical |
| Sep | 29 | Tropical |
| Oct | 28 | Tropical |
| Nov | 28 | Warm |
| Dec | 28 | Tropical |
UV index in San Isidro in Summer
Clear-sky midday UV across summer averages around 13 (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 Isidro peaks around March 16 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 10 (extreme).
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) | 12 | 14 | 15 | 14 | 13 | 13 | 12 | 13 | 13 | 12 | 12 | 10 |
| Level | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 12 | Extreme |
| Feb | 14 | Extreme |
| Mar | 15 | Extreme |
| Apr | 14 | Extreme |
| May | 13 | Extreme |
| Jun | 13 | Extreme |
| Jul | 12 | Extreme |
| Aug | 13 | Extreme |
| Sep | 13 | Extreme |
| Oct | 12 | Extreme |
| Nov | 12 | Extreme |
| Dec | 10 | Extreme |
Where is San Isidro?
San Isidro sits at 9.4°N, 83.7°W, 713 m above sea level, in Costa Rica. The nearest listed city is Manuel Antonio, 51 km away.
Topography around San Isidro
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of San Isidro.
Within 3 km, the terrain around San Isidro has only modest variations in elevation — a maximum elevation change of 211 m around an average of 723 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 2,363 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,764 m.
The land around San Isidro is covered by trees (40%), grassland (31%) and artificial surfaces (28%) within 3 km, trees (71%) and grassland (27%) within 16 km, and trees (67%) and water (22%) within 80 km.
Costa Rica travel facts
- Travel advisory
- Level 2
- Exercise Increased Caution
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 59% of US
- price level, 2025
- GDP per capita
- $19,970
- 2025
- Happiness
- 7.4 / 10
- World Happiness, 2025
- Safe drinking water
- 81%
- of population, 2024
- Homicide rate
- 17.7
- per 100k, 2023
- Road deaths
- 14.8
- per 100k/yr, 2019
- Income group
- High
- World Bank
- English
- Moderate
- EF EPI 516
- 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 Isidro (9.3674°, -83.6971°, elevation 713 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.