San Isidro weather in May

In May, San Isidro sees average daytime highs of 24°C and overnight lows near 21°C, with 730 mm of rain across 30.8 wet days and about 12.4 hours of daylight. It is the 3rd-warmest and 6th-wettest month of the year here.

Day-to-day highs hold fairly steady near 24°C through the month. The sky is clear or mostly clear about 1% of the time in May, and the air most often feels muggy.

Daylight stretches from about 12 h 18 min at the start of May to 12 h 30 min by month's end. Set against the rest of the year, May is San Isidro's 7th-clearest and 7th-windiest month. For the whole year in context, see San Isidro's year-round climate.

Daytime high
24°
3rd warmest
Overnight low
21°
12th coldest
Rainfall
730 mm
30.8 wet days
Daylight
12 h 24 min
5:18 AM – 5:44 PM
Cloud cover
92%
7th clearest
Wind
5 km/h
7th windiest
Solar energy
4.35 kWh/m²
Travel score
3.4
out of 10

San Isidro is district in Pérez Zeledón canton, San José province, Costa Rica.

Density
182/km²
people per km²
Founded
1892

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 24°C through the month.

A typical May day in San Isidro reaches about 24°C in the afternoon and slips back to 21°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 24°C and 25°C. Set against its neighbours, May runs on par with April and on par with June.

20°23°25°28°30°151015202531
Avg high (°C)Avg low (°C)
12421
22421
32421
42421
52421
62421
72521
82521
92521
102521
112521
122421
132421
142421
152421
162421
172421
182421
192421
202421
212421
222421
232421
242421
252421
262421
272421
282421
292421
302421
312421

San Isidro weather by month

How May compares with the rest of the year at a glance. May is the 3rd-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan24° / 20°21025.211.54.8
Feb24° / 20°14021.611.75.1
Mar25° / 21°13825.611.94.7
Apr25° / 21°33028.612.23.8
May24° / 21°73030.812.43.4
Jun24° / 21°70929.912.53.4
Jul24° / 21°8333112.53.4
Aug24° / 21°9333112.33.4
Sep24° / 21°8083012.13.4
Oct24° / 20°95230.811.83.4
Nov24° / 20°92429.911.63.5
Dec24° / 20°41328.811.54.1

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 1% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 4% of May, with mostly cloudy or overcast conditions the remaining 96%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
11288
21090
31090
4991
5892
6793
7793
8793
9694
10694
11694
12694
13496
14496
15397
16397
17397
18298
19298
20298
21199
22199
23199
24199
25199
26199
27199
28199
29199
30199
31199

Chance of precipitation in May

Any precipitation

San Isidro gets around 730 mm of rain over 30.8 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 100% and peaks near 100% on the wettest days.

0%20%40%60%80%100%151015202531
Rain chance (%)
199
299
399
499
599
699
799
899
999
1099
1199
1299
1399
14100
15100
16100
17100
18100
19100
20100
21100
22100
23100
24100
25100
26100
27100
28100
29100
30100
31100

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

Most of May feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, May lands in the muggy band about 86% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Muggy (%)Oppressive (%)
1928
2919
39010
49010
58911
68812
78614
88515
98416
108416
118317
128218
138119
148119
158119
168119
178119
188218
198317
208416
218515
228614
238713
248812
258911
269010
279010
28919
29919
30928
31928

Wind in May

Winds average 5 km/h in May.

Across May, daily wind ranges from about 4 km/h on the calmest days to 5 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
14calm
24calm
34calm
44calm
54calm
64calm
74calm
84calm
94calm
104calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 12 h 18 min at the start of May to 12 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 12 minutes over May. Sunrise moves from 5:22 AM to 5:17 AM, and sunset from 5:42 PM to 5:47 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.35:225:42
212.35:225:42
312.35:225:42
412.35:215:42
512.45:215:42
612.45:215:42
712.45:205:42
812.45:205:43
912.45:205:43
1012.45:195:43
1112.45:195:43
1212.45:195:43
1312.45:195:43
1412.45:195:43
1512.45:185:44
1612.45:185:44
1712.45:185:44
1812.45:185:44
1912.45:185:44
2012.55:185:45
2112.55:185:45
2212.55:175:45
2312.55:175:45
2412.55:175:46
2512.55:175:46
2612.55:175:46
2712.55:175:46
2812.55:175:46
2912.55:175:47
3012.55:175:47
3112.55:175:47

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 4.35 kWh/m².

For context, solar energy here swings from a low near 3.71 kWh/m² to a high of 6.24 kWh/m² in March across the year — May's 4.35 kWh/m² falls in the middle.

024151015202531
Solar energy (kWh/m²)Level
15.0Bright
24.9Bright
34.9Bright
44.8Bright
54.8Bright
64.8Bright
74.7Bright
84.7Bright
94.6Bright
104.6Bright
114.5Bright
124.5Bright
134.4Bright
144.4Bright
154.3Bright
164.3Bright
174.3Bright
184.2Bright
194.2Bright
204.2Bright
214.1Bright
224.1Bright
234.1Bright
244.1Bright
254.1Bright
264.1Bright
274.1Bright
284.1Bright
294.1Bright
304.1Bright
314.1Bright
Planning a trip in May

Hazard calendar for San Isidro

In seasonPeak

In May, San Isidro sits inside 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.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is May a good time to visit San Isidro?

Our two travel scores rate May for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

3.4
Sightseeing
7th-best month of the year
3.1
Beach & pool
6th-best month of the year

May is a weaker month for outdoor sightseeing in San Isidro.

What to pack for San Isidro in May

From May's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In May, San Isidro sees daytime highs around 24°C and nights near 21°C. Pack rain gear. Worth having: light clothes. About 31 days see rain.

rain gearlight clothes

Sea temperature near San Isidro in May

The nearest coast averages about 29°C in May — 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.

26°28°30°32°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan29Tropical
Feb30Tropical
Mar30Tropical
Apr30Tropical
May29Tropical
Jun29Tropical
Jul29Tropical
Aug29Tropical
Sep29Tropical
Oct28Tropical
Nov28Warm
Dec28Tropical

UV index in San Isidro in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeMar 16UV 14Dec 16UV 10
UV index (midday)Level
Jan12Extreme
Feb14Extreme
Mar15Extreme
Apr14Extreme
May13Extreme
Jun13Extreme
Jul12Extreme
Aug13Extreme
Sep13Extreme
Oct12Extreme
Nov12Extreme
Dec10Extreme
Location & terrain

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.

Manuel AntonioParaísoTurrialbaCartagoSan DiegoPatarráSan MiguelAserrí

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.

3 km
211 m
16 km
2,363 m
80 km
3,764 m
treesgrasslandartificial surfaceswatermangroves
May weather nearby: Manuel Antonio 51 km · Paraíso 56 km · Turrialba 60 km · Cartago 60 km · San Diego 68 km · Patarrá 68 km · San Miguel 69 km · Aserrí 70 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
Roman Catholic 48%none 27%Evangelical and Pentecostal 20%other 3%

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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).