Costa Rica Weather by Month, Region by Region, for Canadian Travellers

April and November are change months between the two, according to Costa Rica's national weather service, the Instituto Meteorológico Nacional (IMN). Heat changes far less than rain: Liberia airport in Guanacaste averages a January high of 35.2°C, while Toronto Pearson's average January high is -1.2°C (Environment and Climate Change Canada, 1991 to 2020).

Afternoon rain can change a day's plans in the wet season, and a HelloRoam Costa Rica travel eSIM keeps the forecast, your maps and your messages working from the moment you land at SJO or LIR.

Month-by-Month Highs and Rain Days at Liberia, San José and Limón

IMN publishes climate summaries for Costa Rica's airports. The table gives the average high and the average number of days with rain in each month at Liberia airport in Guanacaste (2005 to 2025), Juan Santamaría airport near San José (2010 to 2025) and Limón airport on the Caribbean coast (2005 to 2025).

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Nights stay mild all year. Average lows run from 17.0°C to 21.3°C at Liberia, 15.7°C to 17.4°C at Juan Santamaría and 18.7°C to 21.7°C at Limón.

Rain totals show how far apart the coasts are. Liberia averages 1.1 mm of rain in January and 338.7 mm in October, about 1,546 mm a year. Juan Santamaría's wettest months are September and October, with about 350 mm and 330 mm. At Limón, July is the wettest month, with 481.6 mm, and September the driest, with 148.6 mm.

The Pacific Side Dries Out From December to March

IMN's study of the North Pacific region, which covers Guanacaste, puts only 4% of the year's rain in the December to March dry period. At Liberia airport, December averages 3 days with rain, and January, February and March 1 each.

In December, Liberia averages a high of 34.5°C and Juan Santamaría 30.3°C, with 3 and 9 days of rain. In January, Liberia's average high is 35.2°C and Juan Santamaría's is 30.8°C, with 1 and 3 days of rain.

The Caribbean is in its rainiest season at the same time. IMN says cold fronts from the north bring the Caribbean slope its heaviest rain from November to January, and Limón averages 24 days with rain in December and 20 in January.

The dry season is also the windy season in Guanacaste. IMN's Liberia airport study finds the strongest winds and the most gusts from January to March, when the trade winds are at their strongest, so check a wind forecast before a boat trip or a day at an exposed beach.

Heat builds toward the end of the dry season. Liberia's average high reaches 37.2°C in March and 37.9°C in April, and the highest reading in its 2005 to 2025 records was 39.7°C, in February. April is the change month: Liberia averages 4 days with rain and Juan Santamaría 10.

The Rainy Season Starts in May and Pauses for the Veranillo

The rains set in during May. On the Pacific side they fall mostly in the afternoon and early evening, IMN says, so plan outdoor time for the morning when you can. The rainy months are also the most humid. At Liberia airport, IMN's records put the dew point, a measure of moisture in the air, at 22°C to 24°C from May to November, and at its lowest in February and March.

In July and August the trade winds pick up and the rain eases on much of the Pacific side and in the Central Valley. Costa Ricans call this break the veranillo or canícula. At Liberia, July averages 13 days with rain, against 19 in June and 18 in August. The Central Valley also gets a short dry spell at the end of June, known as the veranillo de San Juan.

The break is weaker further south. In the Central Pacific's coastal valleys, such as the Parrita valley, IMN says the mountains block the trade winds and the veranillo can disappear, while the Osa Peninsula's stations still show one in July and August.

September and October bring the most rain to the Pacific side and the Central Valley. Juan Santamaría averages 26 days with rain in each, and Liberia 22 and 23. November is the change back toward dry weather.

On the Caribbean Coast, September and October Are the Calmer Months

IMN says the Caribbean slope has no defined dry season: even its least rainy months get 100 to 200 mm of rain. Near the coast it has two calmer spells, February to March and September to October, and rain there is most likely at night and in the morning.

Limón's airport records match that pattern. September is its driest month, with 148.6 mm on 15 days, and October follows with 159.3 mm on 18 days. The wettest months are July, with 481.6 mm on 25 days, and December, with 375.8 mm on 24 days.

IMN notes that the September to October calm falls in the Pacific side's wettest months, so in those weeks the Caribbean is the drier coast.

Costa Rica Has Seven Climate Regions, Not One Season

IMN divides the country into seven climate regions, shaped by its mountains, its winds and its two coasts. The table uses IMN's long-term regional averages for 1961 to 1990, the baseline of its regional climate studies, so its figures differ from the newer airport records above.

The wettest places in the country are in the South Pacific. IMN records 4,000 to 6,000 mm a year on the Osa Peninsula, north of Golfito and around Ciudad Neily.

Height changes the picture inside one region. Monteverde, in the mountains of the North Pacific region, averages a high of 22.3°C and a low of 15.0°C, with 2,483 mm of rain on 205 days a year. The North Pacific as a whole averages 32.8°C, 22.2°C and 136 days of rain.

The Northern Zone, home to Lake Arenal, follows the Caribbean pattern rather than the Pacific one. IMN describes it as rainy all year, with less rain from February to April.

A Very Strong El Niño Is Shaping the 2026 to 2027 Dry Season

IMN's ENSO bulletin of October 2026 rates the current El Niño as very strong. It says sea temperatures in the Niño 3 area of the equatorial Pacific in September 2026 were further above normal than in September of the 1997 and 2015 events, and it expects El Niño to stay very strong from November 2026 to January 2027, then weaken through mid-2027.

For November 2026 to January 2027, IMN's seasonal forecast of 16 October 2026 expects normal dry-season conditions on the Pacific side and in the Central Valley, with average temperatures 1.5°C to 2°C above normal there. For the Caribbean, it expects about 30% less rain than normal and temperatures 1°C to 1.5°C above normal.

IMN's bulletin of the same month says El Niño has so far brought dry conditions to the Pacific side and the Central Valley and a marked rise in rain on the Caribbean slope. With the two pointing different ways for the Caribbean, read IMN's latest update before you book a Caribbean stay. IMN updates both every month.

The Government of Canada's Costa Rica travel advice, last updated on 14 October 2026, also says El Niño conditions are present and may raise the chance of droughts, floods and severe storms.

The Best Month to Visit Depends on the Coast and Your Trip

No single month suits every trip. Match the month to where you are going:

• Dry beach days in Guanacaste: December to March, when Liberia averages 1 to 3 days with rain a month.
• Fewer rainy days in the green season: July, when the veranillo gives Liberia its fewest days with rain between May and October.
• The Caribbean coast: September and October, its calmest months, or February and March.
• Cooler air: the Central Valley and the mountains. Average highs at Juan Santamaría stay between 29.9°C and 33.1°C, and Monteverde's long-term average high is 22.3°C.
• Road trips: the dry season. September and October are the Pacific side's wettest months, and Canada's advice warns that heavy rain can make roads impassable.

If a dry-season beach trip is your plan, our guide to all-inclusive resorts in Guanacaste shows where they sit and what they include.

Heavy Rain, Storms and Strong Currents Come With Official Warnings

Canada's travel advice says heavy rain, mostly from mid-May to the end of November, can cause floods, flash floods and landslides, and roads may become impassable. It puts the hurricane season from mid-May to the end of November in the Pacific, and from early June to the end of November in the Caribbean Sea. If your dates fall in those months, check what Canadian travel insurance covers before you buy a policy.

IMN posts dated weather warnings, in Spanish, on its warnings page.

The same Canadian advice warns that riptides are common and very few beaches have lifeguards. For crime, scams and emergency numbers, read our guide to Canada's risk level for Costa Rica. Rules and advice can change, so read the Government of Canada's Costa Rica page again before you go.

Pack for Afternoon Rain, Lowland Heat and Cool Highland Nights

• A light rain jacket from May to November: for the Pacific side's afternoon showers, and for the Caribbean, which has no true dry season.
• Clothes for heat in Guanacaste: Liberia's average high stays above 33°C in every month of the year.
• A warm layer for the mountains: Monteverde's average low is 15.0°C, and nights at Juan Santamaría average 15.7°C to 17.4°C.

Staying Online From the Pacific to the Caribbean

HelloRoam's Costa Rica plans run on the Claro network. Our Costa Rica plan page listed Claro 4G when we checked it, but the network can change, and the plan page always shows the current one. Claro's coverage map shows its 4G layer for each province, so check it for remote stops before you rely on mobile data there.

Before you fly, check that your phone supports eSIM, then follow our steps to install an eSIM at home over Wi-Fi.

To compare with roaming, Rogers sells Travel Passes by region, including one for Central & South America. Bell's Roam Better cost $16 a day in its international destinations, charged for at most 20 days per line in a billing period; check Bell's list for Costa Rica. For a short resort stay with good Wi-Fi, a pass from your own carrier can be the simpler choice, so check its current price before you fly.

Adding Panama or Colombia to the trip? HelloRoam's South America data plan covers Costa Rica, Panama and Colombia on one eSIM.

We read the IMN climate studies, airport records, ENSO bulletin and seasonal forecast, the Government of Canada's Costa Rica advice, the Rogers and Bell roaming pages and our Costa Rica and South America plan pages on 26 and 27 October 2026.