The Briefing:
- Chulucanas, in Peru's Piura region, hit 38°C (100°F) on Tuesday, Sept. 15 — the highest confirmed reading so far in the current heat wave, according to Senamhi, Peru's weather service.
- Senamhi specialist Nelson Quispe told Andina News Agency that the northern coast will see peaks near 40°C, with a heat index in Piura climbing toward 42°C.
- The government still has 893 districts across 22 regions and the constitutional province of Callao under a state of emergency, and ENFEN, the government's El Niño commission, expects the event to stay active until mid-autumn 2027.
Northern Peru has spent weeks breaking its own thermometer. On Tuesday, Sept. 15, the Chulucanas weather station in the Piura region logged 38 degrees Celsius, the highest figure Senamhi has confirmed so far in this stretch of extreme heat. It's not an isolated spike — it's part of an escalation that began in August and, by the agency's own account, hasn't peaked yet.
A Northern Coast Already Running Hot
The heat wasn't confined to Piura. That Tuesday, September 15, other coastal regions — Tumbes, Lambayeque, La Libertad, Áncash, Lima, Ica, Arequipa and Moquegua — logged extreme conditions of their own, as Chulucanas, in Piura, reached a daytime high of 38 degrees. Across the wider Piura-Tumbes corridor, readings climbed as high as 37.4 degrees, roughly 8 to 9 degrees above the seasonal average of 29 to 30 degrees for this time of year.
Senamhi isn't forecasting a break through the weekend. Under meteorological advisory No. 366, projected highs hold steady from Wednesday the 16th through today, Saturday the 19th: 29 to 36 degrees on the northern coast, 24 to 30 on the central coast, and 22 to 30 on the southern coast. Afternoon gusts were initially forecast near 35 kilometers per hour, though gusts on the central coast topped 36 kilometers per hour on Thursday, with stronger overnight winds along foggy stretches of the shoreline. Thinner midday cloud cover continues to sharpen UV exposure up and down the coast.
Why Forecasters Are Already Talking About 40°C — and a 42°C Heat Index
The explanation starts at sea. Ocean surface warming off the northern coast has already spread to the air above it, Senamhi specialist Nelson Quispe explained to Andina, describing the pattern as an "upward race" between sea and air temperatures. Quispe was blunt about where El Niño Costero currently stands: he put the odds of it reaching extraordinary magnitude above 90%, a sharp jump from the 62% figure ENFEN, the government's multi-agency El Niño commission, had cited just weeks earlier in late August.
Under that scenario, the northern coast could hit peaks near 40 degrees, while the southern coast would top 32 degrees, with Tacna running between 30 and 31. Humidity makes the heat feel worse than the thermometer suggests: in Piura, the heat index could approach 42 degrees, a level officials link to greater risk for children and the elderly, along with heavier sun exposure.
A Phenomenon That Won't Fade by January
It's worth separating the peak from the full length of the event. ENFEN's official Sept. 14 bulletin places the highest odds of El Niño Costero reaching extraordinary magnitude between September 2026 and January 2027, with conditions staying strong to extraordinary through February and March. But the associated conditions, per the commission's own projection, would run through mid-autumn 2027 in the Southern Hemisphere — months longer than the "early 2027" shorthand that tends to circulate.
893 Districts on Alert: El Niño's Other Front
Heat is only half the story. In early September, the executive branch expanded Supreme Decree No. 124-2026-PCM, raising the number of districts under emergency status from 796 to 893, spread across 22 regions and the constitutional province of Callao, over the risk of heavy rains tied to the same phenomenon. The measure, valid for 60 calendar days, classifies the situation as a level-4 emergency — a formal acknowledgment that regional and local governments' response capacity had been outstripped.
The decree doesn't come with extra funding from the national treasury: each regional and local government has to cover its own prevention measures. The technical justification draws a parallel with the 1997 El Niño, one of the most destructive the country has faced, with rainfall expected to hit critical levels on the coast and in the highlands between November and December. Cenepred, Peru's disaster-risk agency, estimates that roughly 20 million Peruvians are at risk, with homes and infrastructure directly threatened.
What Comes Next
Northern Peru is living through its highest documented temperature spike of the season so far, while the rest of the country braces for a rainy season officials themselves are comparing to one of the worst in nearly three decades. With the ocean still warming and spring just getting underway, Senamhi and ENFEN agree on one point: when it comes to temperature, El Niño Costero's worst may still be ahead.
