San Juan weather in May

In May, San Juan sees average daytime highs of 29°C and overnight lows near 23°C, with 271 mm of rain across 26.7 wet days and about 11.8 hours of daylight. It is the 10th-warmest and 3rd-wettest month of the year here.

Day-to-day highs hold fairly steady near 29°C through the month. The sky is clear or mostly clear about 1% of the time in May, and the air most often feels oppressive.

Daylight stretches from about 11 h 54 min at the start of May to 11 h 48 min by month's end. Set against the rest of the year, May is San Juan's 6th-clearest and 7th-windiest month. For the whole year in context, see San Juan's year-round climate.

Daytime high
29°
10th warmest
Overnight low
23°
5th coldest
Rainfall
271 mm
26.7 wet days
Daylight
11 h 48 min
5:54 AM – 5:44 PM
Cloud cover
83%
6th clearest
Wind
4 km/h
7th windiest
Solar energy
3.93 kWh/m²
Travel score
3.2
out of 10

San Juan is human settlement.

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 29°C through the month.

A typical May day in San Juan reaches about 29°C in the afternoon and slips back to 23°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 31°C. Set against its neighbours, May runs on par with April and on par with June.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
12923
22923
32923
42923
52923
62923
72923
82923
92923
102923
112923
122923
132923
142923
152923
162923
172923
182923
192923
202923
212923
222923
232923
242923
252923
262923
272923
282923
292923
302923
312923

How May really feels in San Juan

Once humidity and wind are folded in, May averages 31 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in May is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

San Juan weather by month

How May compares with the rest of the year at a glance. May is the 10th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 24°25225.912.23.0
Feb30° / 24°23324.512.12.9
Mar30° / 24°30428.4122.8
Apr30° / 23°29427.311.92.9
May29° / 23°27126.711.83.2
Jun29° / 23°2192511.83.4
Jul29° / 22°16623.311.83.8
Aug30° / 22°15421.811.93.6
Sep31° / 23°17923.5123.2
Oct31° / 23°20125.912.12.9
Nov30° / 24°23525.812.22.9
Dec30° / 24°26327.212.22.9

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 10% of May, with mostly cloudy or overcast conditions the remaining 89%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
11090
21090
31090
41090
51090
61090
71090
81090
91090
101090
11991
121090
131090
141090
151090
161189
171189
181189
191189
201288
211288
221288
231288
241288
251288
261288
271288
281387
291387
301387
311486

Chance of precipitation in May

Any precipitation

San Juan gets around 271 mm of rain over 26.7 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 87% and peaks near 88% on the wettest days.

0%20%40%60%80%100%151015202531
Rain chance (%)
188
288
387
487
587
686
786
886
985
1085
1186
1286
1386
1486
1586
1686
1786
1886
1987
2087
2187
2287
2387
2487
2587
2687
2787
2887
2987
3086
3186

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the oppressive band about 51% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Muggy (%)Oppressive (%)Miserable (%)
124553
224553
324652
434651
534651
634651
734750
834750
934750
1034749
1134849
1234849
1334848
1434848
1534948
1634948
1735047
1835047
1935047
2035146
2125246
2225345
2325444
2425444
2525543
2625642
2725741
2835740
2935938
3036037
3136136

Wind in May

Winds average 4 km/h in May.

Across May, daily wind ranges from about 4 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
264calm
274calm
284calm
294calm
304calm
314calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 11 h 54 min at the start of May to 11 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 6 minutes over May. Sunrise moves from 5:54 AM to 5:57 AM, and sunset from 5:46 PM to 5:44 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.95:545:46
211.95:545:46
311.95:545:46
411.95:545:46
511.95:545:46
611.95:545:45
711.95:545:45
811.85:545:45
911.85:545:45
1011.85:545:45
1111.85:545:45
1211.85:545:45
1311.85:545:44
1411.85:545:44
1511.85:545:44
1611.85:545:44
1711.85:555:44
1811.85:555:44
1911.85:555:44
2011.85:555:44
2111.85:555:44
2211.85:555:44
2311.85:555:44
2411.85:555:44
2511.85:565:44
2611.85:565:44
2711.85:565:44
2811.85:565:44
2911.85:565:44
3011.85:565:44
3111.85:575:44

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 3.93 kWh/m².

For context, solar energy here swings from a low near 3.76 kWh/m² to a high of 5.14 kWh/m² in September across the year — May's 3.93 kWh/m² sits near the bottom.

012345151015202531
Solar energy (kWh/m²)Level
14.1Bright
24.0Bright
34.0Bright
44.0Bright
54.0Bright
64.0Bright
74.0Moderate
84.0Moderate
94.0Moderate
104.0Moderate
114.0Moderate
124.0Moderate
134.0Moderate
144.0Moderate
154.0Moderate
164.0Moderate
173.9Moderate
183.9Moderate
193.9Moderate
203.9Moderate
213.9Moderate
223.9Moderate
233.9Moderate
243.9Moderate
253.9Moderate
263.9Moderate
273.9Moderate
283.9Moderate
293.8Moderate
303.8Moderate
313.8Moderate
Planning a trip in May

Is May a good time to visit San Juan?

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

3.2
Sightseeing
4th-best month of the year
4.2
Beach & pool
6th-best month of the year

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

What to pack for San Juan in May

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

In May, San Juan sees daytime highs around 29°C and nights near 23°C. Pack light clothes and rain gear. About 27 days see rain.

light clothesrain gear

UV index in San Juan 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 Juan peaks around February 13 at about 16 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near August 14 at about 9 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highExtremeFeb 13UV 16Aug 14UV 9
UV index (midday)Level
Jan15Extreme
Feb16Extreme
Mar15Extreme
Apr12Extreme
May13Extreme
Jun11Extreme
Jul10Extreme
Aug9Very high
Sep12Extreme
Oct12Extreme
Nov12Extreme
Dec12Extreme

Air quality in San Juan 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 Juan is worst in March — around 15 µg/m³ PM2.5 (moderate), about 1.7× the cleanest month (June, 9 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateGoodMar 915 µg/m³Jun 169 µg/m³
PM2.5 (µg/m³)Level
Jan14Moderate
Feb15Moderate
Mar15Moderate
Apr12Moderate
May10Good
Jun9Good
Jul10Good
Aug13Moderate
Sep15Moderate
Oct10Good
Nov11Good
Dec12Moderate
Location & terrain

Where is San Juan?

San Juan sits at 3.8°S, 73.3°W, 99 m above sea level, in Peru. The nearest listed city is Belen, 4.0 km away.

RequenaAtalaia do NorteBenjamin ConstantLeticiaTabatingaYurimaguas

Topography around San Juan

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

Within 3 km, the terrain around San Juan has only modest variations in elevation — a maximum elevation change of 37 m around an average of 94 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 78 m; within 80 km, only modest variations in elevation — a maximum elevation change of 116 m.

The land around San Juan is covered by trees (53%) and artificial surfaces (30%) within 3 km, trees (79%) within 16 km, and trees (96%) within 80 km.

3 km
37 m
16 km
78 m
80 km
116 m
treesgrasslandartificial surfaceswater
May weather nearby: Belen 4.0 km · Iquitos 4.0 km · Requena 156 km · Atalaia do Norte 349 km · Benjamin Constant 367 km · Leticia 374 km · Tabatinga 374 km · Yurimaguas 394 km

Peru travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / B / C
220 V · 60 Hz
Prices
≈ 51% of US
price level, 2025
GDP per capita
$9,684
2025
Happiness
6.0 / 10
World Happiness, 2025
Safe drinking water
49%
of population, 2024
Homicide rate
8.6
per 100k, 2021
Road deaths
13.6
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Moderate
EF EPI 519
Religion
Catholic 76%Evangelical Christian 16%no religion 5%other religions 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 Juan (-3.7761°, -73.2814°, elevation 99 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. 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).