The Catalan Meteorological Service (Meteocat) defines a cold wave as three consecutive days where minimum temperatures fall below the threshold set by the 2nd percentile of data from the 2014-2023 period. For central Barcelona, this means minimums below 3.5 ºC for three days.

The State Meteorological Agency (AEMET) uses a slightly different approach, employing the 5th percentile and relying on data from the 1971-2000 period. This older reference period results in lower thresholds, such as 0.3 ºC at the Barcelona airport station.

Crucially, the AEMET definition also requires a minimum territorial scope, demanding that 10% of meteorological stations in a region exceed the established thresholds. Studies confirm that, in the context of climate change, cold waves are decreasing in frequency, duration, and territorial extension.