Dr. Jeff Masters ·

Above: MODIS satellite image from June 26, 2018 shows clear weather over Oman on the day the 24-hour world high-minimum temperature record was set at Quriyat, Oman. Image credit: NASA.

You may think it’s been hot where you are, but the coastal city of Quriyat (Qurayyat) in the Middle Eastern nation of Oman established a singularly unenviable heat mark on Tuesday: a 24-hour low temperature of 42.6°C (108.7°F), including the period from local midnight to midnight. According to weather records expert Maximiliano Herrera, this sets a new world record for the hottest 24-hour-minimum temperature ever recorded. Herrera says that the previous high-minimum temperature record for any 24-hour period was 41.9°C (107.4°F), set at nearby Khassab Airport in Oman on June 27, 2011. That location also holds the world record for the highest overnight (12-hour) high-minimum temperature: 44.2°C (111.6°F) on June 17, 2017. (Note that the World Meteorological Organization does not maintain world record statistics for highest minimum temperature.)

Figure 1. Bicyclists from Austria, Belgium and France ride during the third stage of the Tour of Oman between the German University of Technology and Wadi Dayqah Dam in the Quriyat area on February 15, 2018. Morning temperatures were surely more comfortable on that day than they were this week! Image credit: Philippe LopezAFP/Getty Images.

The hot weather has been caused by a strong upper-level ridge of high pressure that settled in over the Arabian Peninsula beginning on Sunday. Quriyat’s location on the coast of the Gulf of Oman in the Northern Indian Ocean means that humid marine air keeps the city from cooling off much at night. With sea surface temperatures in the Gulf of Oman at 32°C (90°F), about 1°C (1.8°F) above average for this time of year, these waters were warm enough to allow the city to set the new all-time high minimum temperature record. A listing of the raw 3-hourly synoptic station reports from Quriyat shows that the city remained above 41.9°C (107.4°F) for an incredible 51 straight hours, from 6 UTC June 25 through 9 UTC June 27. The maximum temperature peaked at 49.8°C (121.6°F) on Tuesday, falling a degree short of the all-time heat record for Oman of 50.8°C (123.4°F), set at two locations in Oman last year, at Quriyat on May 30 and at Joba on May 31 (and also at two other locations in 2009 and 1990). Joba, Oman fell just short of tying this record on Wednesday: the high temperature hit 50.6°C. This was, however, the hottest temperature ever recorded in June for Oman (previous June record: 50.4°C on June 26, 2017 at Joba).

In addition to Maximiliano Herrera, thanks go to Michael Theusner of Klimahaus and Jérôme Reynaud of GÉOCLIMAT for alerting me to this event. WU weather historian Christopher Burt has an excellent post from 2016 on the hottest minimum temperatures measured globally up to that point.