Aserrí weather in December

In December, Aserrí sees average daytime highs of 22°C and overnight lows near 14°C, with 88 mm of rain across 13.1 wet days and about 11.4 hours of daylight. It is the 11th-warmest and 9th-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 27% of the time in December, and the air most often feels comfortable.

Daylight stretches from about 11 h 30 min at the start of December to 11 h 24 min by month's end. Set against the rest of the year, December is Aserrí's 4th-clearest and 3rd-windiest month. For the whole year in context, see Aserrí's year-round climate.

Daytime high
22°
11th warmest
Overnight low
14°
4th coldest
Rainfall
88 mm
13.1 wet days
Daylight
11 h 24 min
5:50 AM – 5:15 PM
Cloud cover
58%
4th clearest
Wind
6 km/h
3rd windiest
Solar energy
4.4 kWh/m²
Travel score
6.1
out of 10

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

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

A typical December day in Aserrí reaches about 22°C in the afternoon and slips back to 14°C overnight — a 7°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, December runs on par with November and on par with January.

10°15°20°25°151015202531
Avg high (°C)Avg low (°C)
12115
22115
32115
42114
52114
62114
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 December compares with the rest of the year at a glance. December is the 11th-warmest and 9th-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 December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 27% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 24% of December, with mostly cloudy or overcast conditions the remaining 49%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13367
23466
33664
43664
53763
63763
74060
84060
94258
104258
114456
124555
134654
144753
154951
165149
175248
185545
195644
205842
216040
226139
236337
246436
256535
266535
276733
286733
296733
306832
316832

Chance of precipitation in December

Any precipitation

Aserrí gets around 88 mm of rain over 13.1 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 43% and peaks near 63% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202531
Rain chance (%)
163
261
359
458
556
655
753
852
951
1050
1148
1247
1346
1444
1543
1642
1741
1839
1938
2037
2136
2235
2334
2433
2532
2631
2731
2830
2930
3029
3129

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December lands in the comfortable band about 69% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
156431
256530
356728
466727
566925
676924
787022
887121
997120
10107119
11117118
12127117
13127216
14137215
15147115
16157114
17167113
18177013
19187012
20197011
21206911
22216910
23226810
2423689
2524679
2624679
2725678
2826677
2926677
3027676
3128675

Wind in December

Winds average 6 km/h in December.

Across December, daily wind ranges from about 5 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
15calm
25calm
35calm
45calm
55calm
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 December

DaylightNight

Daylight runs from about 11 h 30 min at the start of December to 11 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 6 minutes over December. Sunrise moves from 5:42 AM to 5:57 AM, and sunset from 5:10 PM to 5:22 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.55:425:10
211.55:435:10
311.55:435:11
411.55:445:11
511.55:445:11
611.45:455:12
711.45:455:12
811.45:465:12
911.45:465:13
1011.45:475:13
1111.45:475:13
1211.45:485:14
1311.45:485:14
1411.45:495:15
1511.45:495:15
1611.45:505:15
1711.45:505:16
1811.45:515:16
1911.45:515:17
2011.45:525:17
2111.45:525:18
2211.45:535:18
2311.45:535:19
2411.45:545:19
2511.45:545:19
2611.45:545:20
2711.45:555:20
2811.45:555:21
2911.45:565:21
3011.45:565:22
3111.45:575:22

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 4.4 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 — December's 4.4 kWh/m² falls in the middle.

024151015202531
Solar energy (kWh/m²)Level
14.0Bright
24.0Bright
34.1Bright
44.1Bright
54.1Bright
64.1Bright
74.2Bright
84.2Bright
94.2Bright
104.2Bright
114.3Bright
124.3Bright
134.3Bright
144.3Bright
154.3Bright
164.4Bright
174.4Bright
184.4Bright
194.5Bright
204.5Bright
214.5Bright
224.5Bright
234.6Bright
244.6Bright
254.6Bright
264.6Bright
274.7Bright
284.7Bright
294.7Bright
304.7Bright
314.7Bright
Planning a trip in December

Hazard calendar for Aserrí

In seasonPeak

None of Aserrí's seasonal hazards are active in December. 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 December a good time to visit Aserrí?

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

6.1
Sightseeing
4th-best month of the year
4.0
Beach & pool
4th-best month of the year

December is a reasonable time to visit Aserrí for sightseeing.

What to pack for Aserrí in December

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

In December, Aserrí sees daytime highs around 22°C and nights near 14°C. Worth packing: rain gear. About 13 days see rain.

rain gear

Sea temperature near Aserrí in December

The nearest coast averages about 28°C in December — 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 December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 10 (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 December

GoodModeratePoorUnhealthyVery unhealthy

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