Rajasthan's Thar Desert, located in northwest India. Image credit: Daniel Mennerich via Flickr // CC BY-NC-ND 2.0

Southern Asia is on the tail-end of one of the worst heat waves seen in this region of the world in modern history, with several countries over the past few weeks measuring the hottest temperatures they’ve ever recorded. The historic warmth started in southeastern Asia during the middle of April, and the stifling heat has spread into India in recent days.

The brutality of this heat wave can seem oddly timed to those of us in the United States. We’re entering the waning days of spring in the Northern Hemisphere, when we expect the warmth and humidity of summer to greet us more frequently than the cool and comfortable days of the not-too-distant past. Even though it’s getting toasty enough to flip on the air conditioner in some regions, the spring we see here isn’t the spring our hemispheric neighbors experience around the world.

April, May, and June are typically the hottest months in southern Asia, where it never really gets all that cool to begin with. It would keep getting hotter through the summer if it weren’t for the monsoon, a seasonal pattern that brings clouds and ample rainfall that help to keep extreme temperatures at bay.

Clear skies over southern Asia allowed the afternoon sun to send temperatures soaring into the triple digits. Image Credit: NASA

This heat wave is the result of a persistent ridge of high pressure stuck over the region, occasionally nudging east (baking southeastern Asia) and jogging back west, where it’s now roasting India.

We tend to use the term “heat wave” loosely these days, but this event wasn’t fooling around. Several countries saw the hottest temperatures they’ve ever officially measured—mostly by just a hair—including a reading of 108.1°F in Laos on April 13 and 108.7°F in Cambodia two days later. Many other countries in the area saw similar (or even warmer) temperatures, but they fell just shy of breaking their all-time high-temperature records.

India also broke its nationwide all-time high temperature on May 19, when the official thermometer in Phalodi saw a high of 123.8°F, beating the previous all-time heat record of an even 123°F set nearby back in 1960. The unlucky town is located almost smack in the middle of the Thar Desert, a few hundred miles west of New Delhi and near the country’s border with Pakistan.

Phalodi’s 123.8°F reading approaches the upper bounds of the type of raw heat the weather is able to generate. Death Valley in California holds the world record for hottest temperature ever verifiably and accurately recorded, where the weather station in the southern California desert measured a high of 134°F on July 10, 1913. Including the Death Valley temperature, the United States has only officially seen two temperatures as hot as what Phalodi experienced during this heat wave: Lake Havasu City, Arizona, and Laughlin, Nevada, recorded temperatures of 128°F and 125°F respectively during a particularly brutal spell on June 29, 1994.

Aside from a brief reprieve (such as it was) from the heat brought about by Cyclone Roanu as it grazed India’s east coast, the intense spell of temperatures higher than 100°F will continue across much of central and northern India, as well as the deserts of Pakistan, through the beginning of June.