San_Ramon_ weather in May

In May, San_Ramon_ sees average daytime highs of 28°C and overnight lows near 21°C, with 381 mm of rain across 29.6 wet days and about 12.5 hours of daylight. It is the 5th-warmest and 5th-wettest month of the year here.

Day-to-day highs hold fairly steady near 28°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 24 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_Ramon_'s 7th-clearest and 8th-windiest month. For the whole year in context, see San_Ramon_'s year-round climate.

Daytime high
28°
5th warmest
Overnight low
21°
12th coldest
Rainfall
381 mm
29.6 wet days
Daylight
12 h 30 min
5:20 AM – 5:48 PM
Cloud cover
88%
7th clearest
Wind
4 km/h
8th windiest
Solar energy
4.62 kWh/m²
Travel score
3.3
out of 10

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 28°C through the month.

A typical May day in San_Ramon_ reaches about 28°C in the afternoon and slips back to 21°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 26°C and 29°C. Set against its neighbours, May runs about 1°C cooler than April and on par with June.

15°20°25°30°151015202531
Avg high (°C)Avg low (°C)
12821
22821
32821
42821
52821
62821
72821
82821
92821
102821
112821
122821
132821
142821
152821
162821
172821
182821
192721
202721
212721
222721
232721
242721
252721
262721
272721
282721
292721
302721
312721

San_Ramon_ weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 20°216.711.56.8
Feb29° / 20°154.211.76.4
Mar30° / 20°247.911.95.6
Apr29° / 21°9820.712.24.1
May28° / 21°38129.612.53.3
Jun27° / 21°41729.812.63.3
Jul27° / 21°32029.912.53.3
Aug27° / 21°39830.412.33.3
Sep27° / 20°44229.812.13.3
Oct26° / 20°50330.711.83.3
Nov26° / 20°26726.511.53.9
Dec27° / 20°7516.311.45.7

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 6% of May, with mostly cloudy or overcast conditions the remaining 92%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
11882
21783
31684
41585
51486
61486
71288
81288
91189
101189
111090
121090
13892
14892
15793
16694
17694
18595
19595
20397
21397
22397
23298
24298
25298
26298
27298
28298
29298
30298
31298

Chance of precipitation in May

Any precipitation

San_Ramon_ gets around 381 mm of rain over 29.6 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 95% and peaks near 100% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%100%151015202531
Rain chance (%)
188
289
390
490
591
691
792
892
993
1093
1194
1294
1395
1495
1596
1696
1797
1897
1998
2098
2198
2298
2399
2499
2599
2699
2799
2899
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 64% of days. Sticky, muggy-or-worse air turns up on roughly 98% of them.

0%25%50%75%100%151015202531
Humid (%)Muggy (%)Oppressive (%)
197615
287616
377617
467618
557619
647620
747521
837522
937423
1037225
1137126
1227028
1326830
1426632
1526533
1616435
1716336
1816138
1916039
2015940
2115841
2215742
2315643
2415544
2515445
2615346
2715148
2815049
2915049
3004951
3104951

Wind in May

Winds average 4 km/h in May.

Across May, daily wind ranges from about 3 km/h on the calmest days to 4 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
114calm
124calm
134calm
144calm
154calm
164calm
174calm
184calm
194calm
204calm
214calm
224calm
234calm
244calm
254calm
263calm
273calm
283calm
293calm
303calm
313calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 12 h 24 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 6 minutes over May. Sunrise moves from 5:25 AM to 5:19 AM, and sunset from 5:46 PM to 5:52 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.45:255:46
212.45:245:46
312.45:245:46
412.45:235:46
512.45:235:46
612.45:235:46
712.45:225:46
812.45:225:47
912.45:225:47
1012.45:225:47
1112.45:215:47
1212.45:215:47
1312.45:215:47
1412.45:215:48
1512.55:205:48
1612.55:205:48
1712.55:205:48
1812.55:205:48
1912.55:205:49
2012.55:205:49
2112.55:205:49
2212.55:195:49
2312.55:195:50
2412.55:195:50
2512.55:195:50
2612.55:195:50
2712.55:195:50
2812.55:195:51
2912.55:195:51
3012.55:195:51
3112.55:195:52

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 4.62 kWh/m².

For context, solar energy here swings from a low near 3.82 kWh/m² to a high of 6.19 kWh/m² in March across the year — May's 4.62 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.2Bright
25.2Bright
35.2Bright
45.1Bright
55.1Bright
65.0Bright
75.0Bright
84.9Bright
94.9Bright
104.8Bright
114.8Bright
124.8Bright
134.7Bright
144.7Bright
154.6Bright
164.6Bright
174.5Bright
184.5Bright
194.5Bright
204.4Bright
214.4Bright
224.4Bright
234.3Bright
244.3Bright
254.3Bright
264.3Bright
274.3Bright
284.3Bright
294.3Bright
304.3Bright
314.3Bright
Planning a trip in May

Hazard calendar for San_Ramon_

In seasonPeak

In May, San_Ramon_ sits inside its rainy season season. The full year is below, with each hazard's peak months called out.

San_Ramon_'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_Ramon_?

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

3.3
Sightseeing
7th-best month of the year
3.6
Beach & pool
7th-best month of the year

May is a weaker month for outdoor sightseeing in San_Ramon_.

What to pack for San_Ramon_ in May

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

In May, San_Ramon_ sees daytime highs around 28°C and nights near 21°C. Pack light clothes and rain gear. Worth having: sun protection. About 30 days see rain.

light clothesrain gearsun protection

Sea temperature near San_Ramon_ 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 29 km away) is warmest in April at about 29°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°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan29Tropical
Feb29Tropical
Mar29Tropical
Apr29Tropical
May29Tropical
Jun29Tropical
Jul29Tropical
Aug29Tropical
Sep29Tropical
Oct28Tropical
Nov28Warm
Dec28Tropical

UV index in San_Ramon_ in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks 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_Ramon_ peaks around February 22 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 10 (very high).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeFeb 22UV 14Dec 17UV 10
UV index (midday)Level
Jan11Extreme
Feb14Extreme
Mar14Extreme
Apr14Extreme
May12Extreme
Jun13Extreme
Jul12Extreme
Aug12Extreme
Sep12Extreme
Oct12Extreme
Nov11Extreme
Dec10Very high

Air quality in San_Ramon_ in May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May falls, not just the annual average.

Air quality in San_Ramon_ is worst in May — around 18 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (January, 9 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodMay 1617 µg/m³Jan 19 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb10Good
Mar11Good
Apr16Moderate
May18Moderate
Jun16Moderate
Jul17Moderate
Aug15Moderate
Sep14Moderate
Oct12Moderate
Nov11Good
Dec9Good
Location & terrain

Where is San_Ramon_?

San_Ramon_ sits at 10.1°N, 84.5°W, 0 m above sea level, in Costa Rica. The nearest listed city is Esparza, 24 km away.

EsparzaQuesadaAlajuelaSan Rafael AbajoChacaritaMercedes NorteSan FranciscoHeredia

Topography around San_Ramon_

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of San_Ramon_.

Within 3 km, the terrain around San_Ramon_ has significant variations in elevation — a maximum elevation change of 294 m around an average of 1,066 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,914 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,414 m.

The land around San_Ramon_ is covered by trees (53%), artificial surfaces (25%) and grassland (21%) within 3 km, trees (68%) and grassland (27%) within 16 km, and trees (61%) within 80 km.

3 km
294 m
16 km
1,914 m
80 km
3,414 m
treesgrasslandcroplandartificial surfaceswatermangroves
May weather nearby: Esparza 24 km · Quesada 27 km · Alajuela 29 km · San Rafael Abajo 35 km · Chacarita 36 km · Mercedes Norte 38 km · San Francisco 39 km · Heredia 40 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_Ramon_ (10.088°, -84.4702°, 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. 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. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).