July was third-hottest on record as tropical nights hit all-time high

Last month was the third-hottest July on record nationwide, with tropical nights occurring more frequently than at any point since observations began, the Korea Meteorological Administration said Wednesday.

In its monthly climate report for July 2026, the KMA said the national average temperature last month was 26.8 degrees Celsius, 2.2 degrees above the historical norm of 24.6 degrees. The figure ranks as the third-highest July average since the country expanded its nationwide weather observation network in 1973. The hottest July on record remains 1994, when the average reached 27.7 degrees, followed by last year at 27.1 degrees.

Nights were particularly severe. The national average number of tropical nights — when the overnight low stays at or above 25 degrees — reached 9.7 days last month, 3.5 times the historical average of 2.8 days and a new all-time record. It surpassed the previous high of 8.8 days set in 2024.

The KMA attributed the persistent nighttime heat to a steady inflow of hot, humid air carried on southwesterly winds, which weakened overnight surface cooling and prevented daytime temperatures from dropping. The national average daily minimum temperature also hit a record high of 23.4 degrees.

Seoul recorded its first tropical night of the season on July 11, 12 days later than last year, but the continued influx of hot, humid air kept nighttime temperatures stubbornly high across the country. Seventeen locations nationwide — including Chungju, Jeonju, Yeosu and Miryang — set new records for the most tropical nights in a single July. Western regions, the southern coast, Jeju and major cities each logged 10 or more tropical nights.

Daytime heat also far exceeded historical norms. The national average number of heat wave days reached 8.9, more than double the historical average of 4.1 days and the fifth-highest on record. The Gyeongsang region bore the brunt, with Daegu enduring 22 heat wave days, Gumi 21 and Miryang 20 — each seeing extreme heat for more than half the month.

The KMA said the prolonged heat wave was driven primarily by the successive influence of the North Pacific High and the Tibetan High pressure systems over the Korean Peninsula.

Heat intensified further across southern regions in late July. Brief relief came when rain fell July 18-20, but temperatures in the Gyeongsang region climbed again quickly as the North Pacific High expanded back over the southeastern part of the country.

South Gyeongsang Province recorded all-time daily high temperatures for four consecutive days July 28-31. Busan reached 38.8 degrees on Wednesday, while Jinju hit 39.0 degrees, Geochang 38.1 degrees and Ulsan 38.0 degrees on Friday.

The heat pattern also revealed a stark regional divide. Central regions received near-normal rainfall due to a stationary front, while the south faced a prolonged stretch of heat waves compounded by drought as the North Pacific High held firm.

National precipitation totaled 220.0 millimeters, just 72.3 percent of the historical average. South Gyeongsang Province was hit hardest, recording only 68.0 millimeters — 21.9 percent of its historical average and the lowest July rainfall ever measured there. The province also logged the most meteorological drought days in the country at 20.7.

"Last July saw heat waves in the first 10 days, heavy rain in the middle of the month and heat waves again at the end, but this year the pattern was clearly polarized by region — heavy rain in the central areas and heat waves with drought in the south," KMA Commissioner Lee Mi-seon said. "We will closely analyze abnormal climate patterns and do our utmost to protect the safety and lives of the public."