“July 24, 2018 was one of the hottest days in California history, as a searing heat wave of rare intensity, even for the Desert Southwest, sent temperatures soaring to near-record levels. Death Valley hit 127°F, just 2° short of tying the all-time world record for hottest reliably recorded temperature; Palm Springs hit 122°F, just 1° short of tying its all-time record; and Imperial, California topped out at 121°F, their hottest day since 124°F was measured on July 28, 1995.
Figure 1. Hourly weather conditions observed in Imperial, California on July 24, 2018, courtesy of NOAA. Rain was observed for four consecutive hours beginning at 3:53 pm PDT, with a temperature of 119°F (48.3°C) occurring during the first two hours of the event. A big thank-you goes to weather records expert Jérôme Reynaud of Géoclimat for bringing this event to my attention.
The temperature might have gone higher on July 24 in Imperial, but clouds streaming in from the Gulf of California brought mostly cloudy skies by mid-afternoon, and rain showers began falling at 3:53 pm PDT. At the time the rain began, the temperature was an astonishingly high 119°F (48.3°C)—a new world record for the hottest temperature ever measured while rain was falling. A series of rain showers continued to affect Imperial in the late afternoon and early evening, with the station recording light rain for four consecutive hours. Most of the rain evaporated since the humidity was only 11 – 15% during the rain event, and only a trace of precipitation was recorded in the rain gauge. Nevertheless, the July 24 rain at 119°F in Imperial sets a new record for the hottest rain in world history.”