Jaco weather in January

In January, Jaco sees average daytime highs of 27°C and overnight lows near 26°C, with 28 mm of rain across 6.3 wet days and about 11.5 hours of daylight. It is the 5th-warmest and 10th-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 68% of the time in January, and the air most often feels oppressive.

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 Jaco's 2nd-clearest and 10th-windiest month. For the whole year in context, see Jaco's year-round climate.

Daytime high
27°
5th warmest
Overnight low
26°
9th coldest
Rainfall
28 mm
6.3 wet days
Daylight
11 h 30 min
6:03 AM – 5:33 PM
Cloud cover
33%
2nd clearest
Wind
9 km/h
10th windiest
Solar energy
5.42 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 27°C through the month.

A typical January 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 29°C. Set against its neighbours, January runs on par with December and on par with February.

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
252826
262826
272826
282826
292826
302826
312826

Jaco weather by month

How January compares with the rest of the year at a glance. January is the 5th-warmest and 10th-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 January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 68% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 15% of January, with mostly cloudy or overcast conditions the remaining 17%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
17723
27723
37723
47822
57822
67921
78020
88020
98119
108218
118218
128218
138317
148317
158317
168416
178416
188416
198416
208416
218515
228515
238515
248515
258614
268614
278713
288713
298713
308812
318812

Chance of precipitation in January

Any precipitation

Jaco gets around 28 mm of rain over 6.3 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 21% and peaks near 34% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%151015202531
Rain chance (%)
134
233
332
431
530
629
728
826
925
1024
1124
1223
1322
1421
1521
1620
1719
1819
1918
2018
2117
2216
2316
2415
2514
2614
2713
2813
2912
3012
3112

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 91% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Muggy (%)Oppressive (%)Miserable (%)
14924
24924
34924
44933
55923
65923
75923
86913
96913
106922
117912
127912
137912
148902
158902
168902
178902
188902
198902
208902
218902
228902
238902
248902
257912
267912
277903
287903
297903
307903
317903

Wind in January

Winds average 9 km/h in January.

Across January, daily wind ranges from about 9 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
29calm
39calm
49calm
59calm
69calm
79calm
89calm
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm
319calm

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 5:58 AM to 6:05 AM, and sunset from 5:25 PM to 5:39 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.45:585:25
211.45:595:26
311.55:595:26
411.55:595:27
511.56:005:27
611.56:005:28
711.56:005:28
811.56:015:29
911.56:015:29
1011.56:015:30
1111.56:025:30
1211.56:025:31
1311.56:025:31
1411.56:025:32
1511.56:035:32
1611.56:035:33
1711.56:035:33
1811.56:035:34
1911.56:045:34
2011.56:045:35
2111.56:045:35
2211.56:045:35
2311.56:045:36
2411.56:045:36
2511.56:045:37
2611.56:045:37
2711.66:045:38
2811.66:055:38
2911.66:055:38
3011.66:055:39
3111.66:055:39

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 5.42 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 — January's 5.42 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.1Bright
25.1Bright
35.2Bright
45.2Bright
55.2Bright
65.2Bright
75.2Bright
85.2Bright
95.3Bright
105.3Bright
115.3Bright
125.3Bright
135.3Bright
145.4Bright
155.4Bright
165.4Bright
175.5Bright
185.5Bright
195.5Bright
205.5Bright
215.5Bright
225.6Bright
235.6Bright
245.6Bright
255.6Bright
265.7Bright
275.7Bright
285.7Bright
295.7Bright
305.8Bright
315.8Bright
Planning a trip in January

Hazard calendar for Jaco

In seasonPeak

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

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
7.7
Beach & pool
3rd-best month of the year

January is one of the better times to visit Jaco for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Jaco in January

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

In January, Jaco sees daytime highs around 27°C and nights near 26°C. Pack light clothes. Worth having: sun protection. About 6 days see rain.

light clothessun protection

Sea temperature near Jaco 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 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 January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 11 (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 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 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
January 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).