Aserrí weather in January

In January, Aserrí sees average daytime highs of 22°C and overnight lows near 14°C, with 29 mm of rain across 5.9 wet days and about 11.5 hours of daylight. It is the 9th-warmest and 11th-wettest month of the year here.

Day-to-day highs hold fairly steady near 22°C through the month. The sky is clear or mostly clear about 44% of the time in January, and the air most often feels comfortable.

Daylight stretches from about 11 h 24 min at the start of January to 11 h 36 min by month's end. Set against the rest of the year, January is Aserrí's 2nd-clearest and 1st-windiest month. For the whole year in context, see Aserrí's year-round climate.

Daytime high
22°
9th warmest
Overnight low
14°
1st coldest
Rainfall
29 mm
5.9 wet days
Daylight
11 h 30 min
6:01 AM – 5:30 PM
Cloud cover
46%
2nd clearest
Wind
6 km/h
1st windiest
Solar energy
5.07 kWh/m²
Travel score
7.4
out of 10

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 22°C through the month.

A typical January day in Aserrí reaches about 22°C in the afternoon and slips back to 14°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 20°C and 23°C. Set against its neighbours, January runs on par with December and on par with February.

10°15°20°25°151015202531
Avg high (°C)Avg low (°C)
12214
22214
32214
42214
52214
62214
72214
82214
92214
102214
112214
122214
132214
142214
152214
162214
172214
182214
192214
202214
212214
222214
232214
242214
252214
262214
272214
282214
292214
302214
312214

Aserrí weather by month

How January compares with the rest of the year at a glance. January is the 9th-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan22° / 14°295.911.57.4
Feb23° / 14°275.611.77.7
Mar23° / 14°409.911.97.0
Apr23° / 15°12319.712.25.1
May22° / 16°45528.812.43.6
Jun22° / 16°45828.912.63.4
Jul22° / 15°34028.112.53.6
Aug22° / 15°43129.312.33.5
Sep22° / 15°50929.912.13.3
Oct22° / 15°53730.211.83.3
Nov21° / 15°29924.911.54.1
Dec22° / 14°8813.111.46.1

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 44% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 28% of January, with mostly cloudy or overcast conditions the remaining 28%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16733
26931
36931
46931
56832
66832
76931
86931
96832
106832
116832
126931
136832
146832
156931
166931
177030
187129
197129
207228
217327
227426
237525
247525
257624
267723
277723
287822
297822
307921
317921

Chance of precipitation in January

Any precipitation

Aserrí gets around 29 mm of rain over 5.9 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 20% and peaks near 28% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%151015202531
Rain chance (%)
128
228
327
427
526
626
725
825
925
1025
1124
1224
1323
1423
1522
1621
1720
1819
1918
2017
2117
2216
2315
2414
2514
2613
2713
2813
2913
3014
3114

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, January lands in the comfortable band about 53% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
129665
230664
331654
432653
533643
634642
735632
836622
937621
1039601
1140591
1242571
1343561
1444551
1546531
1647521
1748511
1849501
1950491
2051481
2152471
2253461
2352462
2453452
2553452
2654442
2755432
2855432
2955423
3055423
3156413

Wind in January

Winds average 6 km/h in January, the windiest month of the year.

Across January, daily wind ranges from about 6 km/h on the calmest days to 6 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in January

DaylightNight

Daylight runs from about 11 h 24 min at the start of January to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 12 minutes over January. Sunrise moves from 5:57 AM to 6:03 AM, and sunset from 5:23 PM to 5:37 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.45:575:23
211.45:575:23
311.45:575:24
411.45:585:24
511.45:585:25
611.45:585:25
711.45:595:26
811.55:595:26
911.55:595:27
1011.56:005:27
1111.56:005:28
1211.56:005:28
1311.56:005:29
1411.56:015:29
1511.56:015:30
1611.56:015:30
1711.56:015:31
1811.56:025:31
1911.56:025:32
2011.56:025:32
2111.56:025:32
2211.56:025:33
2311.56:025:33
2411.56:025:34
2511.56:035:34
2611.56:035:35
2711.56:035:35
2811.56:035:35
2911.66:035:36
3011.66:035:36
3111.66:035:37

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 5.07 kWh/m².

For context, solar energy here swings from a low near 3.74 kWh/m² to a high of 6.04 kWh/m² in March across the year — January's 5.07 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
14.8Bright
24.8Bright
34.8Bright
44.8Bright
54.8Bright
64.8Bright
74.9Bright
84.9Bright
94.9Bright
104.9Bright
115.0Bright
125.0Bright
135.0Bright
145.0Bright
155.0Bright
165.1Bright
175.1Bright
185.1Bright
195.1Bright
205.2Bright
215.2Bright
225.2Bright
235.2Bright
245.3Bright
255.3Bright
265.3Bright
275.3Bright
285.4Bright
295.4Bright
305.4Bright
315.4Bright
Planning a trip in January

Hazard calendar for Aserrí

In seasonPeak

None of Aserrí's seasonal hazards are active in January. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Aserrí'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 January a good time to visit Aserrí?

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

7.4
Sightseeing
2nd-best month of the year
5.1
Beach & pool
3rd-best month of the year

January is one of the better times to visit Aserrí for general sightseeing.

What to pack for Aserrí in January

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

In January, Aserrí sees daytime highs around 22°C and nights near 14°C. Worth packing: sun protection. About 6 days see rain.

sun protection

Sea temperature near Aserrí in January

The nearest coast averages about 29°C in January — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 54 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
Feb29Tropical
Mar30Tropical
Apr30Tropical
May29Tropical
Jun29Tropical
Jul29Tropical
Aug29Tropical
Sep29Tropical
Oct28Tropical
Nov28Warm
Dec28Tropical

UV index in Aserrí in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January 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 Aserrí peaks around March 19 at about 15 (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 19UV 15Dec 16UV 10
UV index (midday)Level
Jan12Extreme
Feb14Extreme
Mar15Extreme
Apr14Extreme
May13Extreme
Jun13Extreme
Jul13Extreme
Aug13Extreme
Sep13Extreme
Oct12Extreme
Nov12Extreme
Dec10Extreme

Air quality in Aserrí 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 Aserrí is worst in May — around 19 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (January, 9 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodMay 1718 µg/m³Jan 149 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb10Good
Mar11Good
Apr17Moderate
May19Moderate
Jun17Moderate
Jul18Moderate
Aug17Moderate
Sep16Moderate
Oct14Moderate
Nov12Good
Dec10Good
Location & terrain

Where is Aserrí?

Aserrí sits at 9.9°N, 84.1°W, 1,338 m above sea level, in Costa Rica. The nearest listed city is San Juan de Dios, 2.0 km away.

Topography around Aserrí

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

Within 3 km, the terrain around Aserrí has large variations in elevation — a maximum elevation change of 871 m around an average of 1,428 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,984 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,764 m.

The land around Aserrí is covered by trees (67%) and artificial surfaces (22%) within 3 km, trees (63%) and artificial surfaces (22%) within 16 km, and trees (67%) within 80 km.

3 km
871 m
16 km
1,984 m
80 km
3,764 m
treesgrasslandcroplandartificial surfacesbare terrainwater
January weather nearby: San Juan de Dios 2.0 km · San Rafael Arriba 3.0 km · San Miguel 4.0 km · San Felipe 5.0 km · Patarrá 7.0 km · San Jose 8.0 km · Curridabat 9.0 km · San Pedro 9.0 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 Aserrí (9.8614°, -84.0927°, elevation 1,338 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).