6am: 43.6ºC According to data published by the NOAA, the mercury dipped to 42.1ºC at 5:25am and 7:30am on Sunday, although the daily minimum temperature listed on their website was 42.0ºC for June 11. Image: Daily temperature extremes at Stovepipe Wells, California on June 11, according to the NOAA. Source: NOAA USCRN But while this was a new US record, it's not the highest minimum temperature in the world. The World Meteorological Organization doesn't maintain records for highest minimum temperature. However, many weather historians recognise 44.2ºC at Khasab Airport, Oman on June 17, 2017 as our planet's highest overnight temperature ever reliably recorded. Another standout temperature from this current heatwave was 54.4ºC at Furnace Creek in Death Valley on Friday, July 9. While this falls short of the official WMO-recognised world record maximum temperature of 56.7C from the same location in 1913, there is also some doubt amongst the weather history community about the legitimacy of that 1913 record.