Desert Downpours: 2021 ranks among top three rainiest monsoons on record

It seems the clouds heard our wishes. 

After record-breaking heat and pitiful rainfall last summer, this year’s monsoon is making up for lost time—and then some. According to the National Weather Service, 2021 already ranks as the third rainiest monsoon ever recorded, and with most of September remaining, forecasters say there’s even a chance this year could hit number one. 

The National Weather Service classifies the monsoon as rainfall Tucson receives between June 15 and the end of September. The greater Tucson area sees an average of 5.69 inches of rain during these three and a half months. Last year, we only saw 1.62 inches, making 2020 the second driest monsoon ever recorded since 1895. This year, we’ve already received more than 12 inches. The all-time monsoonal rainfall record was set in 1964, with 13.84 inches. 

“Depending on how the rain develops over the next month, I think the record is within reach. With all of September left to go, we only have two inches to beat,” said John Glueck, senior forecaster for the National Weather Service in Tucson. “For the most part, this was not expected. There was a prediction for it, because of the relatively dry winter we had…  The early season forecasts had us with a probability of above normal rainfall. But that didn’t quantify the amount of rain we were going to get, just the odds that it would be wetter than normal.” 

The major downpours brought wildflower blooms and turned the flanks of the Catalinas green. However, they’ve also wreaked their share of havoc. Local fire departments like Tucson Fire and Northwest Fire District have conducted multiple swift-water rescues over the summer, assisting motorists trapped in flash flood conditions. In addition, trees, roofs and walls across town have also toppled under the deluge. 

Although 2021 hasn’t yet seen the rainiest monsoon ever, it is still a record-breaking year for weather. This July was the rainiest July on record, with nearly four times as much rain as normal. (Tucson usually sees 2.21 inches of rain in July. This year, the region got 8.06 inches of rain.) Not only was this the rainiest July, but it was also the only month ever recorded to see 8 inches of rain in Tucson. 

This rainfall data is measured from the Tucson Airport. Glueck acknowledges the difficulty in measuring monsoon rain equally across the Tucson area, and says the chances of precipitation increase as you get closer to the mountains. 

“We all know the monsoon can be finicky; one side of the road can get rain and the other won’t. It really depends on where the rain falls for a given monsoon,” Glueck said. “Last year was horrible, we all know that. And statistically speaking, we also knew we would have a better season this year. When you look back at the historical record, you don’t see two really bad years back-to-back. But I don’t think there’s anyone out there who could have said we’d have this strong of a monsoon.” 

However, don’t let the green trails and thunderstorms make you forget about the other weather records broken this year. Mid June, Tucson sweltered under a heat wave (one of many for the Western United States this year) that broke multiple daily heat records. While we never quite beat the all-time high of 117 degrees measured in 1990, parts of Tucson saw upwards of 113 and 115 in June. 

With a warming climate, increased heat is easier to predict as it has a more linear rise. Monsoonal rainfall can be a bit more difficult, changing due to El Nino, winter rains and pressure variants. 

“I think everyone’s happy with what transpired this monsoon, but hopefully they don’t expect it every monsoon because we can flip back to a dry one next year,” Glueck said. “And when you look at studies, especially the latest [Intergovernmental Panel on Climate Change] report, we’re going to much more extremes with the monsoon. We’re warmer, and a warmer atmosphere holds more water, so we may see more extreme rain events than we’ve had in the past. But we’ll also probably see a lot of down monsoons, too. So the idea of normal is just a word. There’s not too much normal anymore. I think what normal is going to be in the future, is the extremes.”