Climate and average weather in Jaco

In Jaco, the weather is muggy, hot, wet, and mostly clear and remarkably steady, with daytime highs holding near hot levels all year. The wettest stretch peaks around October.

Best: early January to late March

Over the course of the year, the temperature in Jaco typically varies from 25°C to 28°C, and is rarely below 25°C or above 29°C. March is the hottest month of the year, while October is the coldest.

Based on the travel score, the best time of year to visit Jaco for warm-weather activities is from early January to late March.

Hottest
Mar
28°
Coldest
Oct
25°
Wettest
Oct
571 mm
Driest
Feb
16 mm
Rain / yr
3507 mm
248 wet days
Daylight
11.4–12.6 h
shortest–longest
Elevation
0 m
9.6°N
Clearest
Feb
27% cloud

Jaco weather by month, at a glance

The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.

Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around early January to late March.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in Jaco, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

Temperatures in Jaco stay fairly even through the year, without a distinct hot or cool season. The warmest month is March, with an average high of 28°C and low of 27°C; the coolest is October, with an average low of 25°C and high of 27°C.

Days typically run about 1°C warmer than nights year-round.

18°20°22°24°26°28°30°32°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan2726
Feb2827
Mar2827
Apr2826
May2826
Jun2726
Jul2726
Aug2726
Sep2725
Oct2725
Nov2725
Dec2726

Average hourly temperature in Jaco

A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on March afternoons, near 28°C, and coldest before dawn in October, near 25°C.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM

Jaco weather by month

Every month at a glance. Click a month for its detailed page.

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

Chance of rain

How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.

Jaco gets about 3507 mm of precipitation a year. On a typical day the chance of rain is very wet, but that rises and falls sharply with the seasons.

The wetter season lasts 7.4 months, from around Apr 21 to Dec 1, peaking in September at about 97% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Feb 3.

October is the wettest month by volume, with 571 mm over about 29 wet days; February is the driest, with 16 mm.

0%10%20%30%40%50%60%70%80%90%100%110%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainoften wetvery wetSep 3 · 97%Feb 3 · 12%
Rain on a day (%)Rain days
Jan216
Feb133
Mar206
Apr6118
May9028
Jun9428
Jul9429
Aug9529
Sep9729
Oct9529
Nov8426
Dec5015

Monthly rainfall

Over a full year, Jaco collects about 3507 mm of rain across 248 wet days — roughly 292 mm in an average month.

It doesn’t fall evenly. October is the wettest month with 571 mm, while February is the driest at just 16 mm. The three wettest months alone bring about 44% of the year’s total.

050100150200250300350400450500550600650JanFebMarAprMayJunJulAugSepOctNovDec281623108405430456506470571371123
Rainfall (mm)Rain days
Jan286
Feb163
Mar236
Apr10818
May40528
Jun43028
Jul45629
Aug50629
Sep47029
Oct57129
Nov37126
Dec12315

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

How often the daytime sky is clear, partly cloudy or overcast.

In Jaco, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.

The clearer part of the year begins around November 22 and lasts for 5.1 months, ending around April 25. The clearest month is February, when the sky is clear, mostly clear, or partly cloudy 87% of the time on average.

The cloudier part of the year begins around April 26 and lasts for 6.9 months, ending around November 21. The cloudiest month is September, when it is overcast or mostly cloudy 96% of the time.

0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JanFebMarAprMayJunJulAugSepOctNovDecFeb 6 · 88%Sep 9 · 3%clearmostly clearpartly cloudymostly cloudyovercastclearercloudierclearer
Clearer (%)Cloudier (%)
Jan8317
Feb8713
Mar7921
Apr4951
May1387
Jun595
Jul595
Aug496
Sep496
Oct793
Nov2872
Dec6535

Daylight, sunrise and sunset

DaylightNight

Hours of daylight through the year, with sunrise and sunset times.

The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 12, brings about 12 h 36 min of light; the shortest, around January 1, only 11 h 24 min — a swing of roughly 1 h 12 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan11.56:035:33
Feb11.76:035:44
Mar11.95:505:46
Apr12.25:325:45
May12.45:225:48
Jun12.65:225:55
Jul12.55:295:59
Aug12.35:335:52
Sep12.15:315:34
Oct11.85:305:17
Nov11.65:375:10
Dec11.45:515:18

Sunny days

How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.

Jaco averages about 8 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 0 and 23 days.

The sunnier stretch runs 4.8 months, from around Nov 30 to Apr 23. The sunniest month is February, with roughly 23 sunny days (brilliant).

The greyest month is August, down near 0 sunny days — about 100% fewer than the February peak.

051015202530JanFebMarAprMayJunJulAugSepOctNovDecsunniergreyersunniergloomymixedbrightbrilliantFeb 623 daysAug 190 days
Sunny daysSky
Jan21Bright
Feb21Brilliant
Mar21Bright
Apr10Mixed
May2Gloomy
Jun0Gloomy
Jul0Gloomy
Aug0Gloomy
Sep0Gloomy
Oct0Gloomy
Nov4Gloomy
Dec14Mixed

Humidity comfort

DryComfortableHumidMuggyOppressiveMiserable

Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.

Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.

Jaco is humid all year round — on a typical day the air feels at least humid, and there is no real dry season to wait for.

The stickiest month is January, when it feels muggy, oppressive or miserable about 100% of the time. Even in January, the mildest month, the air is dry or comfortable only 0% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecmiserableoppressive
Muggy (%)Oppressive (%)Miserable (%)
Jan7913
Feb7885
Mar38611
Apr07030
May06733
Jun08020
Jul08911
Aug09010
Sep0946
Oct0955
Nov1963
Dec2935

Wind

Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Across the year, average wind speed in Jaco is typically calm, near 10 km/h, and varies little with the seasons.

The windier part of the year lasts 3.5 months, from around Jul 31 to Nov 15. The windiest month is October, averaging about 12 km/h (calm).

The calmer part of the year runs from around Nov 16 to May 19, with December the calmest month at about 8 km/h.

051015JanFebMarAprMayJunJulAugSepOctNovDeccalmerwindiercalmercalmlight breezeOct 13 · 12 km/hDec 12 · 8 km/h
Wind speed (km/h)Feels
Jan9calm
Feb9calm
Mar9calm
Apr9calm
May9calm
Jun10calm
Jul10calm
Aug10calm
Sep11calm
Oct12calm
Nov10calm
Dec8calm

Hazard calendar for Jaco

In seasonPeak

When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.

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

Best time to visit Jaco

TravelBeach/poolTemperatureCloudsPrecipitation

To characterize how pleasant the weather is in Jaco throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.

Around late March, Jaco is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.

Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.

The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best time of year to visit Jaco for general outdoor tourist activities is from late December to late March, with a peak score in the first week of February.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timetravel scoretemperaturecloudsprecipitationFeb 3 · 7.9

The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Travel score (0–10)Rating
Jan7.4good
Feb7.8ideal
Mar7.3good
Apr5.1fair
May3.6fair
Jun3.4poor
Jul3.4poor
Aug3.4poor
Sep3.4poor
Oct3.5poor
Nov4.1fair
Dec5.9good

The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit Jaco for hot-weather activities is from late December to early April, with a peak score in the first week of February.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebeach/pool scoretemperaturecloudsprecipitationFeb 6 · 8.3

The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

What to pack for Jaco, by month

EssentialRecommendedOptional

Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.

Jaco packs about the same all year — highs hold near 28°C. Across the year the things worth having are light clothes, sun protection and rain gear.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In March, Jaco sees daytime highs around 28°C and nights near 27°C. Pack light clothes and sun protection. About 6 days see rain.

Sea temperature near Jaco

Average ocean temperature at the nearest coast, month by month, banded into swim-comfort zones — the other half of the beach question.

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 (midday) in Jaco by month

LowModerateHighVery highExtreme

Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.

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

Average hourly UV index in Jaco

LowModerateHighVery highExtreme

Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.

The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

UV falls off far faster than brightness as the sun drops, so even in March the burn window is concentrated in the middle of the day: about 8 hours a day reach index 3 (protection recommended), and 6 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM
UV ≥ 3 (h/day)UV ≥ 6 (h/day)
Jan7.55.5
Feb7.56
Mar86
Apr86
May86
Jun86
Jul86
Aug86
Sep86
Oct7.55.5
Nov7.55
Dec74.5

Air quality in Jaco by month

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly 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
Almanac & agriculture

Growing season

Chance of a frost-free dayFrost-free year round

Jaco is frost-free year round — even the coldest nights rarely reach freezing, so there is no start or end to the growing season.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecfrost-free year round
Frost-free chance (%)Frost nights
Jan1000
Feb1000
Mar1000
Apr1000
May1000
Jun1000
Jul1000
Aug1000
Sep1000
Oct1000
Nov1000
Dec1000

Growing degree days

Degree days (base 10°C)Frost-free shaded

Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Jaco banks about 6,032 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around March.

02,0004,0006,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan518
Feb478
Mar537
Apr513
May519
Jun494
Jul507
Aug506
Sep484
Oct492
Nov478
Dec506

Solar energy

Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

Jaco receives about 5.0 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 4.0 and 6.5 kWh/m².

The brighter stretch of the year lasts 4.5 months, from around Dec 26 to May 12. The brightest month is March, averaging about 6.5 kWh/m² (intense).

The dimmest month is October, down near 4.1 kWh/m² — roughly 36% less than the March peak.

012345678JanFebMarAprMayJunJulAugSepOctNovDecbrighterdimmerdimmoderatebrightintenseMar 166.5 kWhOct 204.0 kWh
Solar energy (kWh/m²)Level
Jan5.4Bright
Feb6.1Intense
Mar6.5Intense
Apr6.0Intense
May4.9Bright
Jun4.5Bright
Jul4.4Bright
Aug4.4Bright
Sep4.5Bright
Oct4.1Bright
Nov4.1Bright
Dec4.8Bright

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
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).