The temperature in Phoenix hit 91 degrees Thursday afternoon, and in Tucson it was 89.
The Phoenix mark tied a record, and Tucson's broke the high for March 14. Tucson's high of 89 degrees on Wednesday also broke the record for that date.
The unusually warm weather comes one week before the official end of winter, on March 20.
The National Weather Service reports that upper-level high pressure is bringing the heat, and it is expected to last one more day before a slight cooling for the weekend.