In the ERA5 dataset February 2025 ended at 1.60ºC above preindustrial February levels.
It is the 3rd hottest February in the ERA5 records.
Global average temperatures are directly linked to what happens in the oceans, with about a 3 month delay. This is what makes the heat in February 2025 so remarkable. Let's take a look at the other two records for context.
- February 2024 was the hottest February on record coming in at 1.77ºC. What is of particular importance is the Relative Oceanic Nino Index (RONI) three months (Nov 2023) prior to this record was +1.6ºC
- February 2016 was next highest February ever recorded at 1.65ºC. In this case the RONI in November 2015 was +2.6ºC
- Which brings us to the 2025 February value of 1.60ºC. The remarkable thing is that the RONI in November 2024 was -0.8ºC basically in the heart of the La Niña and yet this much cooler ocean index didn't stop the global average from being at the level it was.
Something has clearly changed in the system.