Tropical Storm Ileana is cooling down the Valley. Here’s how much

Tropical Storm Ileana weakened into a tropical depression as it hit mainland Mexico on Sunday. But it’s still going to bring cooler temperatures and possibly some rain to the Valley.

Monday, much of Maricopa County has between a 20-30% chance of rain, according to the National Weather Service. The rainfall could be light – less than 0.1 inches – but points farther east could get heavier rainfall.

But what’s more certain is that Phoenix will get a (relative) break from the summer heat. According to National Weather Service Phoenix Meteorologist Mark O’Malley, Ileana coming from the south combined with another storm system from the north will cause temperatures to fall over the next several days.

Phoenix is “expecting a lot of cloud cover” and moisture in that stretch, O’Malley said, and the NWS projects highs of 93-95 degrees from Tuesday through Friday. That would be a lower temperature than is normal for this time of year in the Valley. Typically, mid-September still means temperatures above 100 degrees. Even more appealing are the projected lows in the 60s.

Despite cooling temperatures, triple-digit days will likely return before long – the NWS projects for a return of “above normal” temperatures by Sunday.

“Phoenix typically does not see its last 100-degree day until the beginning of October,” O’Malley said. In late August, NWS Meteorologist Alex Young estimated Phoenix’s last 100-degree day to be Oct. 5 this year.