On Thursday, they measured 110°F, which is 43.3°C, at a station near the community of Martinez Lake, Arizona. This value broke the previous record for March for the entire US. The old record was tied on Wednesday, when California hit 108°F (42.2°C).
Temperatures above 40 °C were measured at seven other stations in California and Arizona. Normal temperatures for this period are around 20 °C lower. The March record was recorded for the states of California, Nevada, Arizona, Wyoming and Utah.
In Phoenix, which has a metropolitan area of about 5 million people, the temperature soared to 40.6 °C (105 °F), the earliest 40 on record, a new March record and also tying the April record for the station. Many other stations also exceeded the value for April.
In addition, temperatures may rise to even higher levels in the coming days, with above-average temperatures across the continental United States. There’s even a chance that a hotter temperature could be reached than the current US April record of 45 °C (113 °F) set in 2012.
Behind the high temperatures is the high pressure, which is maintained in the area for a longer time, and the so-called heat dome effect, which amplifies the high temperatures even more. There is also very dry air under this “dome”, which can be seen in satellite images.
Temperatures will drop across the rest of the US next week, but temperatures in Southern California and Arizona should remain well above average.
Such a pronounced and long-lasting heat wave is truly unique. According to scientists from World Weather Attribution, such high temperatures would be virtually impossible without human-caused climate change. According to them, due to climate change, maximum temperatures during this heat wave are about 4 °C higher than they would be without it.
