Jaco weather in December

In December, Jaco sees average daytime highs of 27°C and overnight lows near 26°C, with 123 mm of rain across 15.2 wet days and about 11.4 hours of daylight. It is the 9th-warmest and 8th-wettest month of the year here.

Day-to-day highs hold fairly steady near 27°C through the month. The sky is clear or mostly clear about 45% of the time in December, and the air most often feels oppressive.

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 Jaco's 4th-clearest and 12th-windiest month. For the whole year in context, see Jaco's year-round climate.

Daytime high
27°
9th warmest
Overnight low
26°
7th coldest
Rainfall
123 mm
15.2 wet days
Daylight
11 h 24 min
5:51 AM – 5:18 PM
Cloud cover
48%
4th clearest
Wind
8 km/h
12th windiest
Solar energy
4.75 kWh/m²
Travel score
5.9
out of 10

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 27°C through the month.

A typical December day in Jaco reaches about 27°C in the afternoon and slips back to 26°C overnight — a 1°C spread between the day's warmth and the night's chill. On most days the high lands between 26°C and 28°C. Set against its neighbours, December runs on par with November and on par with January.

20°23°25°28°30°151015202531
Avg high (°C)Avg low (°C)
12726
22726
32726
42726
52726
62726
72726
82726
92726
102726
112726
122726
132726
142726
152726
162726
172726
182726
192726
202726
212726
222726
232726
242726
252726
262726
272726
282726
292726
302726
312726

Jaco weather by month

How December compares with the rest of the year at a glance. December is the 9th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan27° / 26°286.311.57.4
Feb28° / 27°163.411.77.9
Mar28° / 27°235.811.97.3
Apr28° / 26°10818.412.25.1
May28° / 26°40528.312.43.6
Jun27° / 26°43028.412.63.4
Jul27° / 26°4562912.53.4
Aug27° / 26°50629.412.33.4
Sep27° / 25°47029.112.13.4
Oct27° / 25°57129.311.83.5
Nov27° / 25°37125.611.64.1
Dec27° / 26°12315.211.45.9

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 45% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 20% of December, with mostly cloudy or overcast conditions the remaining 34%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15149
25248
35347
45347
55545
65545
75644
85842
95842
105941
116040
126139
136238
146337
156535
166634
176733
186832
196931
207129
217228
227327
237426
247525
257624
267624
277723
287723
297624
307624
317723

Chance of precipitation in December

Any precipitation

Jaco gets around 123 mm of rain over 15.2 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 49% and peaks near 69% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
169
267
366
464
563
661
760
858
957
1056
1155
1253
1352
1451
1550
1648
1747
1846
1945
2044
2143
2242
2341
2440
2539
2638
2737
2836
2936
3035
3135

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December lands in the oppressive band about 93% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Muggy (%)Oppressive (%)Miserable (%)
11945
21945
31945
41945
51945
61936
71936
82926
92926
102926
112935
122935
132935
142935
152935
162935
172935
183934
193934
203934
213934
223934
233934
243934
253934
263934
273934
283934
293934
303934
314924

Wind in December

Winds average 8 km/h in December, the calmest month.

Across December, daily wind ranges from about 8 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
19calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
188calm
198calm
208calm
218calm
228calm
238calm
248calm
258calm
268calm
278calm
289calm
299calm
309calm
319calm

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 5:44 AM to 5:58 AM, and sunset from 5:13 PM to 5:25 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.55:445:13
211.55:445:13
311.55:455:13
411.55:455:13
511.55:465:14
611.55:465:14
711.55:475:14
811.55:475:15
911.55:485:15
1011.55:485:16
1111.45:495:16
1211.45:495:16
1311.45:505:17
1411.45:505:17
1511.45:515:18
1611.45:515:18
1711.45:525:18
1811.45:525:19
1911.45:535:19
2011.45:535:20
2111.45:545:20
2211.45:545:21
2311.45:555:21
2411.45:555:22
2511.45:565:22
2611.45:565:23
2711.45:575:23
2811.45:575:24
2911.45:575:24
3011.45:585:25
3111.45:585:25

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 4.75 kWh/m².

For context, solar energy here swings from a low near 4.12 kWh/m² to a high of 6.51 kWh/m² in March across the year — December's 4.75 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
14.4Bright
24.4Bright
34.4Bright
44.5Bright
54.5Bright
64.5Bright
74.5Bright
84.5Bright
94.5Bright
104.6Bright
114.6Bright
124.6Bright
134.6Bright
144.7Bright
154.7Bright
164.7Bright
174.7Bright
184.8Bright
194.8Bright
204.8Bright
214.9Bright
224.9Bright
234.9Bright
244.9Bright
255.0Bright
265.0Bright
275.0Bright
285.0Bright
295.1Bright
305.1Bright
315.1Bright
Planning a trip in December

Hazard calendar for Jaco

In seasonPeak

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

Jaco'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 Jaco?

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

5.9
Sightseeing
4th-best month of the year
6.0
Beach & pool
4th-best month of the year

December is a reasonable time to visit Jaco for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Jaco in December

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

In December, Jaco sees daytime highs around 27°C and nights near 26°C. Pack light clothes and rain gear. Worth having: sun protection. About 15 days see rain.

light clothesrain gearsun protection

Sea temperature near Jaco 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 offshore 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 Jaco in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Jaco peaks around March 15 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 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 highMar 15UV 13Dec 17UV 9
UV index (midday)Level
Jan11Extreme
Feb13Extreme
Mar13Extreme
Apr13Extreme
May12Extreme
Jun13Extreme
Jul11Extreme
Aug12Extreme
Sep12Extreme
Oct11Extreme
Nov11Extreme
Dec9Very high

Air quality in Jaco 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 Jaco 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 Jaco?

Jaco sits at 9.6°N, 84.6°W, 0 m above sea level, in Costa Rica. The nearest listed city is Esparza, 42 km away.

EsparzaChacaritaSan Rafael AbajoTejarPuntarenasSan_Ramon_Manuel AntonioAlajuela

Topography around Jaco

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

Within 3 km, the terrain around Jaco has significant variations in elevation — a maximum elevation change of 401 m around an average of 35 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 802 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,811 m.

The land around Jaco is covered by water (38%) and trees (31%) within 3 km, water (56%) and trees (35%) within 16 km, and trees (45%) and water (43%) within 80 km.

3 km
401 m
16 km
802 m
80 km
2,811 m
treesgrasslandcroplandartificial surfacesbare terrainwatermangroves
December weather nearby: Esparza 42 km · Chacarita 44 km · San Rafael Abajo 44 km · Tejar 46 km · Puntarenas 46 km · San_Ramon_ 55 km · Manuel Antonio 57 km · Alajuela 64 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 Jaco (9.615°, -84.6298°, 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).