La Fortuna Costa Rica Weather: Arenal Volcano Climate Guide

La Fortuna de San Carlos sits in the Arenal basin on the lower slopes of Costa Rica's Central Volcanic Cordillera. Unlike Guanacaste to the northwest, La Fortuna does not have a true dry season—it receives significant rainfall in every month of the year due to its position between the Pacific and Caribbean moisture systems.

Annual rainfall in La Fortuna averages 100–130 inches (2,540–3,300 mm), making it considerably wetter than San José or Guanacaste beach towns. The relative 'dry season' from December through April brings reduced—but not absent—rainfall, while the peak rainy season of September and October can see extraordinary amounts of precipitation.

Despite the rain, La Fortuna is one of Costa Rica's most popular destinations year-round. The La Fortuna Waterfall, Arenal Volcano, and numerous hot springs are all accessible regardless of season. Smart travelers plan morning activities and embrace the afternoon rains as part of the experience.

The dry season in La Fortuna runs roughly from December through April, though it's a relative term. Even during the driest months, La Fortuna typically receives 4–7 inches (100–178 mm) of rain per month—compared to Guanacaste which may get under 1 inch in February. The key difference during dry season is that rains become more predictable afternoon events rather than all-day affairs.

January and February offer the best conditions for seeing Arenal Volcano. Clear mornings occur more frequently, and while clouds often build by midday, the chance of getting a clear volcano view is highest during these months. Sunrise is often the best time, when the volcano stands crisp against the blue morning sky.

The dry season also brings more comfortable hiking conditions on forest trails around the Arenal area. Muddy paths are less challenging, and the slightly lower humidity makes physical activity more comfortable. Hanging bridges walks, lava fields exploration, and the hike to the La Fortuna Waterfall are all more comfortable in the dry season.

The rainy season (May through November) brings daily afternoon and evening rains to La Fortuna, with September and October being the wettest months. Monthly rainfall can exceed 20 inches (508 mm) during peak months. The La Fortuna Waterfall reaches its most spectacular levels during the rainy season, swelling dramatically with the increased flow.

Despite heavier rainfall, the rainy season in La Fortuna is highly rewarding for nature lovers. The surrounding Arenal Volcano National Park and Monteverde Cloud Forest (about 2 hours away) are intensely green and lush. Bird activity is heightened, particularly for species like toucans, tanagers, and resplendent quetzals in the higher elevation forests.

Hot springs are particularly enjoyable during the rainy season—the warm pools feel wonderful when afternoon rains cool the air, and the combination of steam rising from the springs with tropical rain creates an atmospheric experience. The hot springs remain at consistent temperatures (95–104°F/35–40°C) regardless of season.

January: High 82°F (28°C), Low 68°F (20°C), Rainfall 4.5 in (114 mm). Driest and clearest month. Best volcano viewing chances.

February: High 83°F (28°C), Low 68°F (20°C), Rainfall 3.5 in (89 mm). Excellent conditions. Very dry by La Fortuna standards.

March: High 85°F (29°C), Low 70°F (21°C), Rainfall 4.8 in (122 mm). Warmest month. Still relatively dry with good morning clarity.

April: High 85°F (29°C), Low 71°F (22°C), Rainfall 7.2 in (183 mm). Rains increasing. Still good conditions, especially early in the month.

May: High 83°F (28°C), Low 70°F (21°C), Rainfall 11.8 in (300 mm). Rainy season arrives. Morning activities still excellent.

June: High 82°F (28°C), Low 70°F (21°C), Rainfall 13.4 in (340 mm). Consistently rainy afternoons. Lush vegetation peaks.

July: High 81°F (27°C), Low 70°F (21°C), Rainfall 12.6 in (320 mm). Waterfall at high flow. Fewer tourists than dry season.

August: High 81°F (27°C), Low 70°F (21°C), Rainfall 14.0 in (356 mm). Similar to July. Good hot springs weather.

September: High 80°F (27°C), Low 69°F (21°C), Rainfall 18.5 in (470 mm). Wettest month. Deepest discounts. Limited volcano visibility.

October: High 80°F (27°C), Low 69°F (21°C), Rainfall 20.2 in (513 mm). Very wet. Spectacular waterfall flow. Best for budget travelers.

November: High 80°F (27°C), Low 69°F (21°C), Rainfall 12.8 in (325 mm). Rains tapering. Improving conditions through month.

December: High 81°F (27°C), Low 68°F (20°C), Rainfall 6.8 in (173 mm). Dry season returning. Good volcano views begin returning.

Arenal Volcano's iconic cone is notoriously cloud-covered, and seeing it clearly is never guaranteed—even in the dry season. The best strategy is to arrange your itinerary so you have multiple mornings in La Fortuna, maximizing your chances of catching a clear view. Sunrise and early morning offer the highest probability of clear skies before clouds build.

The west side of the lake (from La Fortuna town and most hotels) and the east side (Lake Arenal area) offer different viewing angles. Some hotels are positioned specifically to offer volcano views from private terraces or infinity pools. January and February have the highest frequency of clear mornings.

Arenal erupted actively from 1968 through 2010. Since then, it has been in a resting phase with no major lava flows. The volcano is still geologically active—it emits steam and occasional small tremors—but the dramatic lava flows of the active period are not currently visible. The cone itself remains spectacular when visible.

La Fortuna's volcanic hot springs are a major attraction and are enjoyable year-round. The springs are fed by geothermal activity unrelated to surface weather conditions, maintaining consistent temperatures of 95–104°F (35–40°C) regardless of season. On rainy season evenings after afternoon storms, the contrast between the warm spring water and cool air is particularly magical.

The La Fortuna Waterfall, accessed via a 500-step staircase descent into a canyon, is dramatic in any season but reaches its most spectacular volumes during the rainy season (June–October). The turquoise-green pool at the base is accessible for swimming in both seasons, though the current is stronger and swimming is more limited during peak flow.

January and February offer the best overall conditions for visiting La Fortuna—the highest probability of clear Arenal views, the most comfortable hiking conditions, and reasonable (if peak-season) prices. December is also excellent, particularly for travelers who enjoy the festive holiday atmosphere.

For budget-conscious travelers willing to accept more rain, May through August offer a good compromise: prices are 20–30% lower than peak season, mornings are usually clear, the La Fortuna Waterfall is spectacular, and the hot springs are enjoyable. September and October offer the deepest discounts but come with the heaviest rains and least frequent volcano views.