Weather update from Karen Mogensen Reserve: when does the rainy season start? 🌧️
Let’s take a look at the weather conditions recorded during the first 22 days of April at the Karen Mogensen Reserve in Costa Rica.
In 2025, daily average temperatures remained similar to those of the previous year, around 27–28°C. However, while 2024 saw more extreme heat peaks (reaching up to 36.8°C on April 1 and 14), the 2025 maximums were slightly lower, though still seasonally high.
The contrast in rainfall is more evident: 2024 was almost entirely dry up to April 17, with only one significant rainfall event (13.4 mm on April 10). In contrast, 2025 has already seen two notable rain events on April 6 and 7 (11 mm and 20 mm respectively), plus a minor rainfall on April 22. It’s worth noting that 2024 lacks data for some days due to equipment issues.
These signs suggest the imminent onset of the rainy season. Supporting this, the Instituto Meteorológico Nacional (IMN) forecasts the rainy season to begin in the Nicoya Peninsula in early May.
📍 Luca Lombroso, Meteorologist AMPRO
Foreste per Sempre OdV & Osservatorio Geofisico di UNIMORE