Nights as warm as 21°C in winter: Lima and Callao complete 70 days of unusual heat, Senamhi explains

Lima and Callao are enduring an unprecedented stretch of warm winter nights, with the phenomenon now reaching 70 consecutive days above normal temperatures. The Peruvian National Meteorology and Hydrology Service (Senamhi) reports that since May 6, various parts of the capital have recorded nighttime temperatures significantly higher than typical for this season, a situation attributed to the lingering effects of the El Niño Costero phenomenon.

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Lima and Callao are going through an episode of nighttime heat that has already reached 70 consecutive nights.

This persistent warmth is causing nighttime temperature anomalies of up to 5 to 6 degrees Celsius above average. While the entire capital is affected, Callao has registered the highest temperatures, with other districts also experiencing a prolonged period of unusually warm nights. Senamhi specialist Lourdes Menis explained that El Niño Costero, while primarily impacting the north, is altering atmospheric conditions along the central coast, keeping minimum temperatures elevated.

Menis noted that while brief warm spells occurred earlier, the current event is the most extended. In central Lima, the Jesús María station has recorded 64 consecutive nights with temperatures between 18°C and 20.6°C, far exceeding the July average of 15.4°C. La Molina also reports winter minimums between 16.4°C and 19.2°C.

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This event is related to the presence of the El Niño Costero Phenomenon, which maintains a greater influence over the north of the country, but also modifies the atmospheric conditions of the central coast.

Callao, in particular, continues to lead in nighttime warmth. The Jorge Chávez airport station has recorded nightly temperatures between 20°C and 21.6°C, compared to the usual July norm of around 16°C. Since June 28, all recorded nights in Callao have been classified as extremely warm. Menis recalled that during the 2023 El Niño event, Callao experienced 142 consecutive warm nights, but the current event began nearly a month earlier, leading to an earlier onset of elevated temperatures. The proximity to the sea is cited as a factor, as the ocean retains heat and releases it slowly at night.

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The proximity to the sea favors this behavior, as the ocean stores heat during the day and releases it slowly at night.