The Canary Islands experienced their hottest October on record since 1961, with an average temperature of 23.8 degrees Celsius, marking a significant temperature deviation of 3.6 degrees Celsius above normal. This information was highlighted in the Aemet‘s ‘Avance Climatológico’, published on a Tuesday, which underscored the extraordinary heatwave that swept across the islands.
Furthermore, the month saw considerably low rainfall, with an average accumulation of just 18.9 litres per square metre, which is a mere 59% of what is typically expected for October, rendering it the 27th driest October in records dating back to 1961.
The enduring heat led to a phenomenon where tropical nights—where temperatures do not fall below 20 degrees Celsius—occurred daily in various parts of the archipelago. Notable locations included the meteorological centre in Santa Cruz de Tenerife, Mogán on Gran Canaria, Fuencaliente on La Palma, and several sites on El Hierro, La Gomera, and Fuerteventura.
In total, an unprecedented count of 1,629 tropical nights and 322 torrid nights—where temperatures exceed 25 degrees Celsius—were documented. This is a sharp increase from the previous year, which saw 769 tropical nights and no torrid nights.
Temperature records were broken, with Sabinosa on El Hierro hitting a high of 40.6 degrees Celsius on October 4th. The warmest minimum temperature, recorded at the Teguise heliport, was 27.2 degrees Celsius. The highest average monthly temperatures were observed in Tasarte on Gran Canaria and at the Tenerife South airport station, each with an average of 27.4 degrees Celsius.
A significant heatwave spanned 16 days, marking the lengthiest since 1975 and the third such event of the year, leading to 2023 being the year with the second-highest number of heatwave days—a total of 26.
This exceptional weather pattern began to take shape in late September when the Atlantic anticyclone shifted west of the Iberian Peninsula and tracked towards Central Europe. Concurrently, a Tropical Upper Tropospheric Trough (TUTT) cell positioned south of the Azores, and the westward movement of the African ridge settled over the Canary Islands, alongside a weak pressure gradient over the archipelago.
This combination fostered a south-southeast airflow that brought intense warmth and dryness, spiking temperatures and carrying dust for most days of the event, peaking on the 7th and 8th.
The weather pattern shifted on October 17th when the Atlantic anticyclone repositioned over Central Europe and the African high pressure moved eastward. This transition allowed an Atlantic front, associated with the storm ‘Babet’, to bring some rainfall to the Canary Islands. Consequently, the airflow over the islands changed, leading to a gradual decrease in temperatures, particularly after October 21st.