Tucson Weather Alert: Extreme Heat and Monsoon Threats Incoming—What to Expect This Week

A wet winter system is drenching Tucson this week, ending an unusually dry December and ushering in a sharp cool-down across southern Arizona. According to the National Weather Service in Tucson, widespread rain will linger through tonight as the storm’s core slides eastward, keeping skies gray and roads slick. Hour-by-hour radar from The Weather Channel shows precipitation chances holding near 100 % through the overnight hours, tapering to scattered showers after sunrise. Temperatures will top out only in the mid-50s today—nearly 15 ° below the early-January average—and plunge to the mid-30s before dawn Friday. Forecasters say one more round of light rain and isolated thunder is possible Friday afternoon, followed by clearing skies and a run of colder, drier nights that could flirt with freezing in outlying desert valleys. Keep pets and sensitive plants protected as overnight lows hover between 32 °–36 ° through Saturday morning. Rainfall totals of 0.30″–0.75″ are common across metro Tucson, with higher pockets in the foothills. Although this storm is not triggering flash-flood watches, low-water crossings in Pima County may close briefly where heavier downpours develop, so allow extra commute time and never drive through flooded washes. Weekend outlook and warming trend • Saturday: Mostly sunny, high near 57 °, morning low 34 °. • Sunday: Abundant sunshine, high around 59 °, low 40 °. • Monday–Wednesday: A gradual warming trend pushes daytime highs into the mid-60s to upper 60s, while nights stay crisp in the upper 30s to low 40s. Another weak Pacific wave could brush the region late next week, but confidence remains low. What this means for Tucsonans 1. Outdoor events: Plan for umbrellas today, but organizers can expect improving conditions by Saturday afternoon. 2. Snow watchers: Mount Lemmon may pick up 2–4 ″ of fresh snow; Highway 39 restrictions are possible. 3. Allergy relief: The soaking rain will temporarily knock down dust and pollen, offering a brief respite for allergy sufferers. Stay ahead of changing Tucson weather by checking real-time radar, road conditions and updated forecasts before heading out.