Monsoon

A 2018 monsoon rolls through Green Valley and Sahuarita. 

The first taste of intense summer heat and consistent 100-degree days will hit this week.

The National Weather Service in Tucson is forecasting triple-digit highs throughout the week, with the hottest days hitting over the weekend.

Green Valley and Sahuarita could see a high of 109 on Sunday, and the Tucson area could see temperatures as 110 degrees the same day.

Though the high temperatures early in the summer may be surprising, Rob Howlett, a meteorologist with the National Weather Service in Tucson, said they’re not unexpected.

“We’ve kind of had an average start to June so far,” he said.

“And looking ahead into the summer, it’s becoming that typical trend where we have higher chances of above-normal temperatures,” Howlett said, based on forecasts from the Climate Prediction Center.

According to the NWS, Tucson sees a monthly average temperature of 86 degrees in June, with a monthly high around 101 degrees. The record high for the month is June 26, 1990, when the temperature climbed to 117 degrees.

The triple-digit highs arriving this week are only slightly earlier than the National Weather Service’s historical averages, which includes temperature back to 1895.

According to the year-by-year records, the first 105-degree day hits the Tucson area around June 11, on average, and the first 110-degree day arrives around June 29.

The first triple-digit day this summer arrived on May 13, which was just slightly earlier than the historical average of May 25.

Normal monsoon

The lack of precipitation in the Tucson area over the past year has also ranked it as the driest 12-month period on record since 1900.

But the Climate Prediction Center is still calling for the 2021 monsoon to look slightly wetter than the 2020 season, which concluded with 1.6 inches of rain and was the second-driest season on record. The driest monsoon on record totaled 1.59 inches in 1924.

The Climate Prediction Center’s outlook for the next three months is forecasting equal chances for both above-normal, normal and below-normal precipitation across most of Arizona.

Howlett said the ambiguity stems from a lack of strong indicators pointing one way or the other.

“One of the things that can be a predictive element is the El Niño or the La Niña, and right now it’s actually in a neutral phase, so there’s no strong signal coming from that,” Howlett said.

“The other thing we can look at is the snowpack in the Rocky Mountains, and that can indicate that we might have a slightly earlier onset to the monsoon here in the Southwest,” he said.

“But you can’t always bank on that. Seasonal forecasting is still in development and hard to get 100 percent right, 100 percent of the time,” he said.

Looking at next week, Howlett said an increase in moisture coming from the south in Mexico could bode well for more storm activity in our area, but right now it’s still a waiting game.

“As far as the Tucson area is concerned, because there are no strong signals at this point, it’s kind of looking like your normal monsoon season,” he said.

Monsoon season officially kicks off June 15, and lasts through Sept. 30, with most rainfall occurring in July and August.

If the predictions for a typical monsoon hold true, the Tucson area could see five to six inches of rain this summer.

Mary Glen Hatcher | 520-547-9740

Mary Glen is a North Carolina native who's excited to explore the Tucson area through her reporting with Green Valley News. She graduated from UNC-Chapel Hill's Hussman School of Journalism and Media in 2019.