There’s an argument to be made for June 20th, 2017 being the hottest recorded day in Tucson.
Weather record keeping for the Old Pueblo began in 1894. Tuesday’s high temperature reached 116° yesterday, which is the 2nd hottest recorded daytime high in Tucson. While unofficial, Tucson may have reached its earliest 100° reading at 8:02 AM.
In addition, the morning low Tuesday was a balmy 87°, which is the warmest June low temperature on record.
How does this add up to yesterday being the city’s hottest day?
Between the daytime high and morning low, Tucson’s average temperature yesterday was 101.5°. According to the National Weather Service, this is the first time Tucson has ever recorded an average daily temperature at or above 100°.
But what about June 26th, 1990?
That’s when Tucson recorded its hottest daytime high, reaching 117°. The low temperature that morning was 80°, putting the average daily temperature at 98.5°. Quick math places June 26th, 1990’s average temperature 3° cooler than yesterday’s mark.