Costa Rica Temperature Guide: What to Expect Year-Round

Costa Rica's unique geography creates dramatic temperature differences over very short distances. The country spans from sea level to nearly 12,500 feet (3,820 meters) at the summit of Cerro Chirripó, the highest peak in Central America. This elevation range produces temperature differences of 40–50°F (22–28°C) between the coast and the highest peaks.

A useful rule of thumb: temperatures drop approximately 3.5–5°F (2–3°C) for every 1,000 feet (300 meters) of elevation gain. This means a drive from sea-level Jacó at 90°F (32°C) to San José at 3,800 feet can reduce the temperature by nearly 15°F (8°C). The drive from San José up to the Poás Volcano crater rim at 8,800 feet drops temperatures another 20°F (11°C).

Latitude plays a smaller role in Costa Rica's temperatures. Located between 8° and 11° north latitude, the country remains tropical year-round, and the sun is almost directly overhead at midday throughout the year. Seasonal temperature variation is minimal compared to the elevation effect—coastal temperatures vary only about 5–8°F (3–4°C) between the warmest and coolest months.

Costa Rica's Pacific coast is warm and humid year-round. Sea-level temperatures rarely drop below 75°F (24°C) even at night and can reach 95–100°F (35–38°C) in March and April at the peak of the dry season in Guanacaste. Average daytime highs on Pacific beaches range from 85–95°F (29–35°C) depending on the month and location.

Guanacaste (Pacific Northwest) is the hottest and driest region: Tamarindo, Flamingo, Nosara, and Sámara regularly see afternoon temperatures of 90–95°F (32–35°C) during the dry season (December–April). The northeast trade winds provide some cooling, but the overall climate is genuinely hot. March is the hottest month, with some days exceeding 100°F (38°C) in inland areas.

The Central Pacific coast (Jacó, Manuel Antonio) is slightly cooler than Guanacaste due to higher rainfall and more vegetation. Average highs of 85–90°F (29–32°C) are typical year-round. The Southern Pacific around the Osa Peninsula is similar in temperature to the Central Pacific but significantly wetter, with the rain moderating temperatures.

The Caribbean coast temperatures are similar to the Pacific—80–88°F (27–31°C) average highs year-round—but feel hotter due to consistently higher humidity (85–90% year-round). The Caribbean doesn't experience the Pacific's relatively drier dry season, so the humidity never drops as dramatically.

The Central Valley, home to San José (elevation 3,800 ft/1,160 m), Alajuela (3,300 ft/1,000 m), Heredia (3,800 ft/1,160 m), and Cartago (4,700 ft/1,430 m), enjoys the most pleasant year-round temperatures in Costa Rica. The region is often described as having 'eternal spring' conditions.

San José temperatures: Average daily highs range from 75–82°F (24–28°C), with the warmest months being March and April (82–84°F/28–29°C) and the coolest being December and January (77–79°F/25–26°C). Overnight lows range from 60–67°F (15–19°C) throughout the year, with December and January producing the coolest nights at 60–62°F (15–17°C). Absolute record lows in San José are around 50°F (10°C) during unusually cold fronts from the north.

The valleys around the Central Valley sit at varying elevations. The Orosí Valley (south of Cartago), the Reventazón Valley, and the Turrialba Valley all offer slightly different microclimates, generally warmer at the valley floor (where elevations may drop to 2,000–2,500 feet) and cooler on the surrounding ridgelines.

Costa Rica's mountain ranges—the Talamanca Mountains, the Central Volcanic Cordillera, and the Tilarán Mountains—experience dramatically cooler temperatures than the lowlands. At these elevations, Costa Rica's tropical latitude matters less than the altitude.

Monteverde Cloud Forest (elevation 4,600 ft/1,400 m): Average highs of 65–72°F (18–22°C), lows of 54–60°F (12–15°C). Feels cool and misty most of the year, requiring a jacket or light fleece year-round. The windy season (January–March) can make temperatures feel colder.

Chirripó National Park summit (12,500 ft/3,820 m): Temperatures range from 30–50°F (0–10°C). Freezing temperatures occur regularly at night. Snow is extremely rare but has been recorded on exceptional cold fronts. Hikers must bring serious cold-weather gear including hat, gloves, insulated jacket, and thermal base layers.

Poás Volcano (crater rim at 8,800 ft/2,700 m): Average temperatures of 45–55°F (7–13°C). Frequently windy and misty. A fleece jacket or wind-resistant layer is necessary for crater rim visits regardless of the season.

Despite popular belief, Costa Rica's seasonal temperature change is modest compared to the rainfall change. The difference between the warmest and coolest months at sea level is only about 5–8°F (3–4°C).

Dry Season (December–April): Pacific coast highs of 85–95°F (29–35°C), lows of 70–76°F (21–24°C). March and April are the hottest months—Guanacaste can exceed 95°F (35°C) on some afternoons. Lower humidity (65–75% relative humidity) makes the heat more manageable than the numbers suggest.

Rainy Season (May–November): Pacific coast highs of 82–88°F (28–31°C), lows of 72–76°F (22–24°C). Slightly cooler than dry season due to cloud cover and rain. Higher humidity (80–90%) makes equivalent temperatures feel hotter. September and October see slightly cooler days due to overcast skies.

The Central Valley follows a similar seasonal pattern but at cooler temperatures. The dry season in San José peaks at 80–84°F (27–29°C), while the rainy season settles at 75–80°F (24–27°C) for highs.

Hottest: The Guanacaste lowlands, including the area around Liberia, Filadelfia, and the Tempisque River basin, regularly record the highest temperatures in Costa Rica. In March and April, temperatures of 100–104°F (38–40°C) in the shade are recorded in this agricultural valley. The Guanacaste coast is moderated by sea breezes and typically stays 5–8°F (3–4°C) cooler than the inland areas.

The Caribbean lowlands around Limón and Siquirres also experience significant heat combined with very high humidity, creating some of the highest heat index values in the country. Limón averages about 80°F (27°C) year-round but with near-constant 85–90% humidity.

Coolest: The Chirripó summit is the coldest point in Costa Rica, with year-round average temperatures near freezing at night and frost forming regularly. The highland valleys of Dota, Copey, and the areas above 8,000 feet (2,440 m) experience the coolest daily temperatures, with nights regularly in the 40s°F (4–9°C).

The single biggest packing mistake travelers make in Costa Rica is not accounting for the dramatic temperature differences between regions. A visitor going from Guanacaste (90°F/32°C) to Monteverde (60°F/15°C) on consecutive days needs clothing appropriate for both environments.

Universal packing list for Costa Rica temperature zones: Lightweight breathable shirts and shorts for coastal areas; 1–2 long pants for evenings and cool highland areas; a light fleece or jacket for Monteverde, Arenal evenings, and San José nights; a warm layer (heavier fleece or down vest) for Chirripó, Poás crater visits, or high-elevation overnight stays; quick-dry fabric throughout; swimwear for all beach and hot spring visits.