Tuesday, July 6, 2021
It’s no surprise to hear last year’s monsoon was wimpy — only 0.03 inches of rain away from being the driest Tucson monsoon ever recorded, according to the National Weather Service. And while rising heat is relatively predictable, climate change seems to have a less linear impact on rainfall, with monsoons ranging from weak to powerful over the past decade. Luckily, this year’s monsoon is off to a much better start than last year.
We’re less than a week into July 2021, and Tucson has already seen more rain than in the entire month of July 2020. The National Weather Service reports that we've already seen half an inch of rain in the first few days of July, beating the 0.46 inches of rain seen throughout all of July 2020, as measured at the Tucson airport.
The contrast is even stronger when comparing Junes. This June saw 0.17 inches of rain, compared to none last year.
Since 2008, the National Weather Service has defined the monsoon as rainfall between June 15 and Sept. 30. Prior to 2008, the monsoon start date was determined when the average daily dewpoint was 54 degrees or greater for three consecutive days.