San Juan weather in January

In January, San Juan sees average daytime highs of 30°C and overnight lows near 24°C, with 252 mm of rain across 25.9 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 5th-wettest month of the year here.

Day-to-day highs hold fairly steady near 30°C through the month. The sky is clear or mostly clear about 3% of the time in January, and the air most often feels oppressive.

Daylight stretches from about 12 h 12 min at the start of January to 12 h 12 min by month's end. Set against the rest of the year, January is San Juan's 8th-clearest and 1st-windiest month. For the whole year in context, see San Juan's year-round climate.

Daytime high
30°
4th warmest
Overnight low
24°
12th coldest
Rainfall
252 mm
25.9 wet days
Daylight
12 h 12 min
5:57 AM – 6:08 PM
Cloud cover
84%
8th clearest
Wind
5 km/h
1st windiest
Solar energy
4.63 kWh/m²
Travel score
3.0
out of 10

San Juan is human settlement.

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

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 30°C through the month.

A typical January day in San Juan reaches about 30°C in the afternoon and slips back to 24°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 32°C. Set against its neighbours, January runs on par with December and on par with February.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
13024
23024
33024
43024
53024
63024
73024
83024
93024
103024
113024
123024
133024
143024
153024
163024
173024
183024
193024
203024
213024
223024
233024
243024
253024
263024
273024
283024
293024
303024
313024

How January really feels in San Juan

Once humidity and wind are folded in, January 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 January is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

San Juan weather by month

How January compares with the rest of the year at a glance. January is the 4th-warmest and 5th-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 January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 3% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 6% of January, with mostly cloudy or overcast conditions the remaining 91%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
11090
21090
31090
41090
51090
6991
7991
8991
9991
10991
11991
121090
13991
14991
15991
16991
17892
18793
19793
20793
21793
22793
23793
24793
25892
26892
27892
28892
29892
30892
31892

Chance of precipitation in January

Any precipitation

San Juan gets around 252 mm of rain over 25.9 wet days in January. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 83% and peaks near 84% on the wettest days.

0%20%40%60%80%151015202531
Rain chance (%)
184
284
384
484
584
684
784
883
983
1083
1183
1283
1383
1483
1583
1683
1783
1883
1983
2083
2183
2283
2383
2483
2584
2684
2784
2884
2984
3084
3184

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, January lands in the oppressive band about 57% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Muggy (%)Oppressive (%)Miserable (%)
105446
205545
315445
415445
515445
615544
715544
815643
915643
1015742
1115742
1215841
1305941
1405941
1505941
1605941
1705941
1805941
1905941
2005941
2105941
2205941
2305941
2405842
2505842
2605842
2705743
2805743
2905644
3005644
3105545

Wind in January

Winds average 5 km/h in January, the windiest month of the year.

Across January, 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
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
184calm
194calm
204calm
214calm
224calm
234calm
244calm
254calm
264calm
274calm
284calm
294calm
304calm
314calm

Sunrise & sunset in January

DaylightNight

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

Days grow by about 0 minutes over January. Sunrise moves from 5:50 AM to 6:02 AM, and sunset from 6:03 PM to 6:11 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.25:506:03
212.25:506:03
312.25:516:04
412.25:516:04
512.25:526:04
612.25:526:05
712.25:536:05
812.25:536:06
912.25:546:06
1012.25:546:06
1112.25:546:07
1212.25:556:07
1312.25:556:07
1412.25:566:08
1512.25:566:08
1612.25:576:08
1712.25:576:09
1812.25:576:09
1912.25:586:09
2012.25:586:09
2112.25:586:10
2212.25:596:10
2312.25:596:10
2412.25:596:10
2512.26:006:11
2612.26:006:11
2712.26:006:11
2812.26:016:11
2912.26:016:11
3012.26:016:11
3112.26:026:11

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 4.63 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 — January's 4.63 kWh/m² falls in the middle.

024151015202531
Solar energy (kWh/m²)Level
14.6Bright
24.6Bright
34.6Bright
44.6Bright
54.6Bright
64.6Bright
74.6Bright
84.6Bright
94.6Bright
104.6Bright
114.6Bright
124.6Bright
134.6Bright
144.6Bright
154.6Bright
164.6Bright
174.6Bright
184.6Bright
194.6Bright
204.6Bright
214.6Bright
224.7Bright
234.7Bright
244.7Bright
254.7Bright
264.7Bright
274.7Bright
284.7Bright
294.7Bright
304.7Bright
314.7Bright
Planning a trip in January

Is January a good time to visit San Juan?

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

3.0
Sightseeing
6th-best month of the year
4.2
Beach & pool
5th-best month of the year

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

What to pack for San Juan in January

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

In January, San Juan sees daytime highs around 30°C and nights near 24°C. Pack light clothes and rain gear. Worth having: sun protection. About 26 days see rain.

light clothesrain gearsun protection

UV index in San Juan in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 15 (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 January

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where January 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
January 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).