At around 4:30 am on Tuesday, Jan 21st, the first measurable rain of 2020 fell at Phoenix Sky Harbor! Phoenix measured 0.19 inches of rain for the day, which also happens to be the yearly total.
Out of 125 years of weather records in Phoenix, this is the 33rd time that the first day of measurable rain has occurred on or after January 21st. There have been a total of 11 years with no measurable rain in January.