When is monsoon season in Phoenix?
The National Weather Service dates the Arizona monsoon June 15 to September 30. Storms in that window are short and intense, bringing microbursts, blowing dust, lightning and flash flooding, and the NWS Phoenix office issues flash flood watches and warnings through the season.
Rainfall totals explain why the season does so much damage in so little time. Sky Harbor's recent normals run about 7.22 inches a year, with roughly 2.43 inches of that falling in the monsoon, so a large share of the year's rain arrives in a handful of violent storms rather than steady winter rain.
The record for a single day there is 3.29 inches, set on September 8, 2014 as moisture from Hurricane Norbert moved over the state; sections of I-10 and I-17 closed and parts of Chandler recorded close to six inches. That is the scale the season is capable of, and it is why roofs and scuppers are worth checking in May.
Why does my roof only leak during a monsoon storm?
Because wind, not rain, finds the weakness. Sideways rain gets under tile and behind flashing where a vertical drip never reaches, and wind lifts or shifts tile that looks fine from the ground. A worn underlayment or a cracked coating can stay dry for months and leak in one storm.
Ponding is the other mechanism. On a flat or foam roof, blown debris blocks the scuppers and drains, water sits where it was meant to run off, and a coating that has taken a decade of sun gives way under it. Clearing roof debris after the season and keeping a foam roof recoated are both roofing work, and the guide to foam, flat and tile roof leaks explains how each type fails.
From inside, the giveaway is almost never above the stain. Water lands on sheathing, runs along framing and soaks insulation before it finally shows on drywall, which is why roof leak water damage work starts with an attic inspection rather than a ceiling patch.
What happens on the first visit after a storm?
Protection, then assessment. A tarp or board-up closes the opening so the next cell cannot refill the building, the attic and ceiling are checked with meters and a thermal camera, water on the floor is extracted, and drying equipment goes in before the crew leaves, with readings and photos recorded.
Storms arrive in clusters, so the first visit treats another one tonight as likely rather than hypothetical. Anything left open gets covered, and belongings under a wet ceiling get moved out of the way.
Power outages often come with these storms, and equipment needs power to dry a house. Tell the crew if your electricity is out, because that changes what can be set up and what has to wait.
Does insurance cover storm damage and wind-driven rain?
Standard homeowners policies often cover storm damage, including rain that entered through an opening the wind created, while they generally exclude flood, meaning surface water and runoff from washes and streets. The distinction is how the water got in, and your insurer decides under your own policy.
Keep the two paths separate when you report it. Rain through a wind-damaged roof is usually a homeowners claim, while water that sheeted across the yard and under the garage door falls under flood insurance, which is a separate policy: flood damage cleanup covers that side of the work.
Photograph the roof, the opening and every stained ceiling before anything is tarped or moved, and keep the tarp in the pictures as well. The crew documents moisture readings and removed materials for you, and coverage is decided by your insurer.