July 2026 Sets New Records at Karen Mogensen Reserve. Attention Now Turns to a Possible Super El Niño
The weather station at Karen Mogensen Reserve, operating continuously since 2017, has recorded an unprecedented result: July 2026 was both the warmest and the driest July of the entire observational record.
The monthly statistics are remarkable:
- 🌡️ Mean temperature: 27.0 °C
- 🌡️ Mean maximum temperature: 32.1 °C
- 🔥 Absolute maximum temperature: 34.6 °C
- 🌧️ Monthly rainfall: 90.0 mm
For comparison, July 2025 recorded:
- 🌡️ Mean temperature: 26.1 °C
- 🌡️ Mean maximum temperature: 30.7 °C
- 🌧️ Rainfall: 120.2 mm
Compared with last year:
- +0.9 °C in monthly mean temperature;
- +1.4 °C in mean daily maximum temperature;
- about 25% less rainfall.
Beyond the records themselves, what is most significant is the combination of persistent heat and below-normal rainfall, increasing water stress on the tropical forest and its ecosystems.
A relatively short but increasingly valuable climate record
Although the station has been operating for only nine years, the dataset is already sufficient to identify meaningful trends and climate anomalies.
Karen Mogensen Reserve provides an excellent natural laboratory for monitoring climate variability in one of Central America’s biodiversity hotspots.
Focus now shifts to the Pacific Ocean
Seasonal forecasts from ECMWF consistently indicate the development of a very strong El Niño, with Niño 3.4 sea surface temperature anomalies exceeding +3 °C during late 2026.
If confirmed, this could become one of the strongest El Niño events on record.
For Costa Rica, particularly the Pacific slope, strong El Niño events are typically associated with:
- reduced rainfall;
- longer dry periods;
- above-average temperatures;
- increased stress on forests, biodiversity and water resources.
We will continue monitoring the evolution of this event closely and documenting its impacts through observations from our weather station at Karen Mogensen Reserve.