Costa Rica Weather and Climate Guide 2026

Costa Rica experiences two main seasons across most of its territory: a dry season from December to March and a rainy season spanning May to October. However, 2026 proves to be an atypical year. The national weather service, Instituto Meteorológico Nacional (IMN), anticipates a rapid intensification of El Niño, which has already caused drought conditions on the Pacific side and within the Central Valley.

Experts predict a drier and hotter autumn for the Guanacaste region and San José, while the Caribbean coast remains relatively unaffected.

Costa Rica is divided into seven climate regions by the towering mountain range running from northwest to southeast. This natural barrier splits the country into distinct weather patterns on the Pacific and Caribbean slopes. The IMN divides the nation into seven climate regions, including the North, Central, and South Pacific regions, the Central Region, the Northern Zone, and the North and South Caribbean.

On the Pacific slope, the dry season begins earliest in the northwest and lingers latest in the southeast. March typically marks the driest and hottest month of the year. Rain returns in May, followed by a brief interruption known as the veranillo, or canícula, in July and August. During this period, trade winds strengthen, often bringing temporary relief from the persistent heat and humidity.

The Caribbean slope, in contrast, lacks a consistent dry season. Rainfall is relatively uniform throughout the year, with an average of 100 to 200 millimeters per month. Although the coast experiences two relatively dry spells - from February to March and from September to October - the latter coincides with the Pacific's peak rainfall season. Rainfall on the Caribbean coast typically occurs at night and in the early morning hours.

The figures provided by the IMN represent long-term averages based on data collected from 1961 to 1990. According to the latest seasonal outlook released on September 11, 2026, the IMN observed unusually rapid warming of sea temperatures in the Niño 3.4 region of the Pacific. In August, these temperatures reached about 2.5 degrees Celsius above normal, surpassing levels seen during the intense El Niño events of 1997 and 2015.

This confirms that El Niño has firmly established itself and is likely to continue its intensifying trend towards the end of 2026.

The IMN's early-warning system indicates that meteorological drought is expected to persist in the Central Valley, the western Northern Zone, and the Pacific region. For September, the IMN forecasts rainfall to be 80% below normal in the North Pacific, 60% below in the Central and South Pacific, and 50% below in the Central Valley.

In October to December, the outlook predicts dry-season conditions on the Pacific slope and in the Central Valley, with rainfall 30% below normal in the western Northern Zone, while the Caribbean slope and the eastern Northern Zone experience normal rainfall. The IMN also anticipates an early end to the rainy season, a weaker and later sequence of cold fronts from the north, and temperatures 1.5 to 2 degrees Celsius above normal on the Pacific side and in the Central Valley.

The Atlantic hurricane season in Costa Rica runs from June 1 to November 30. Storms originating in the Caribbean Sea typically bring rain to the Pacific slope rather than the Caribbean coast. For instance, Hurricane Mitch in 1998 dumped approximately 900 millimeters of rain around Jacó and Quepos on the Pacific side, while the Caribbean coast remained largely unaffected.

Hurricane César in 1996, although much weaker, caused casualties and extensive damage in Costa Rica. For 2026, the IMN anticipates a less active Atlantic season than usual, with a range of 9 to 12 named systems. This includes 5 to 6 tropical storms, 3 to 4 minor hurricanes, and 1 to 2 major hurricanes, along with 41 tropical waves. However, even a relatively quiet season cannot rule out the possibility of a devastating storm.

For travelers, those planning to visit Pacific beaches and San José should aim for the reliable dry season between December and March. The Caribbean coast offers relatively dry windows from February to March and again from September to October. During the autumn of 2026, the IMN's outlook indicates an early onset of dry conditions on the Pacific side, with noticeably hotter temperatures than usual in all regions.

Residents considering a move to Costa Rica should take note of the varying weather patterns when evaluating properties. In September and October, the wettest months, it is advisable to assess the resilience of roads, roofs, and drainage systems, particularly in drought-prone areas like Guanacaste. Remote workers and retirees should also be aware of the distinct rainfall patterns on both coasts - predominantly at night and in the morning for the Caribbean, and in the afternoon for the Pacific.

Adhering to the IMN's warnings during severe weather events is essential for ensuring safety and comfort.