When is pool season in Phoenix? For most families the water is inviting from late spring until the nights cool in fall, and the pool keeps running all year in between. The catch is that the hottest months of that season are also monsoon months, when dust storms, wind and lightning can turn a sparkling pool brown in an afternoon. This guide answers the season question with climate data, then walks through what monsoon storms do to a desert pool and the safe steps to take before, during and after one.
Phoenix Pool Cleaning Pro is a free phone line, not a pool company. If a storm leaves more than you want to handle, call (623) 240-0428 any hour and you will be put through to an independent local pool service company that looks at the pool, quotes and does the work itself.
When is pool season in Phoenix? What the climate data says
No agency declares a pool season, so the best guide is the weather. The National Weather Service office in Phoenix publishes 30-year normals for Sky Harbor Airport, covering 1991 to 2020. A normal is simply the average for that month over those 30 years. Here are the normal average highs for the warm part of the year.
| Month | Normal average high | What it means for the pool |
|---|---|---|
| March | About 78 degrees | Pleasant days, but the water is still cool for most swimmers without a heater |
| April | About 86 degrees | Water warming; many people start using the pool on the warmest days |
| May | About 95 degrees | Swimming weather for most of the Valley |
| June | About 104 degrees | Peak use, long pump run times; the monsoon officially starts June 15 |
| July | About 107 degrees | Monsoon season in full swing; heavy load on filters and chlorine |
| August | About 105 degrees | Monsoon continues; dust and debris after storms |
| October | About 89 degrees | Monsoon over since September 30; still swimmable for many people |
So pool season in Phoenix, in the swimming sense, runs roughly from May into October for most people, with April and late October depending on how warm you like the water. A pool heater can stretch those months. In the care sense, there is no off season. The pump, the filter and the chlorine keep working through December and January, because warm afternoons and sunshine let algae grow in a pool that is ignored.
The same question asked about all of Arizona has no single answer, since the state's high country is far cooler than the low desert. This guide covers the Phoenix metro only.
What the monsoon and a haboob do to a backyard pool
The National Weather Service treats June 15 through September 30 as the official monsoon season, the stretch when its hazards are most likely. NWS Phoenix outlook material notes that 30 to 60 percent of Arizona's yearly rain falls in those months, with the share varying from place to place.
Dust storms
A haboob is a wall of dust pushed ahead of a thunderstorm by its outflow winds. A NOAA technical memo describes these walls reaching from several hundred meters to a couple thousand meters high. NWS Phoenix reports that in an average year one to three dust storms move into the Phoenix area, mostly from the southeast. Fine dust settles in every open pool it crosses, clouds the water and loads the filter quickly.
Wind and debris
Outflow winds strip leaves, palm fronds, seed pods and gravel from yards and drop them in the water. Skimmer and pump baskets can fill in minutes, and a full basket starves the pump of water. Loose patio umbrellas, cushions and toys become missiles; SRP and APS both note that wind can carry umbrellas, trampolines and kiddie pools into power lines.
Rain
A heavy storm adds rainwater all at once, washes deck dirt and landscape gravel into the pool, and can raise the water level near the top of the skimmer. Rain dilutes the water and the debris it brings in uses up chlorine, so the balance you had in the morning may be gone by evening. The only way to know is to test.
Power outages
Storms knock down poles and lines; APS reported crews replacing more than 400 power poles in a single week of severe storms in 2022. When the power drops, the pump stops, the chlorinator or salt cell stops, and dirty warm water sits still. That is how a pool goes from dusty to green.
Monsoon pool care: before, during and after a storm
Every step below is a safe homeowner step. Nothing here involves opening electrical equipment, handling chemicals beyond reading a test kit, or going near the pool while a storm is overhead.
Before the storm season and before each storm
- Close and tie down patio umbrellas, or take them down and store them.
- Bring in or secure cushions, floats, toys and lightweight furniture.
- Empty the skimmer and pump baskets so they start the storm with room.
- Note the filter's pressure reading so you can compare after.
- Keep the water level normal, about halfway up the skimmer opening.
- Sign up for your utility's outage alerts, from SRP or APS.
During the storm
- Everyone out of the pool at the first thunder or sign of a storm.
- Shelter in a building. A covered patio or shade sail does not protect you.
- Stay away from the equipment pad, the pool and metal fences while there is lightning.
- Skip showers and dishwashing while lightning is close, since plumbing can carry a strike.
- Leave the pump as it is if it is running safely; do not go out to change it.
- If the power goes out, SRP suggests turning off appliances so a surge does not hit them when power returns. Do it only from inside, at a switch or control you can reach dry.
After the storm passes
- Wait 30 minutes after the last thunder before going outside to the pool.
- Look for downed lines. Stay at least 100 feet away and call 911 and your utility.
- Skim leaves and debris; empty the skimmer and pump baskets again.
- Check the pump is running and the timer or automation kept its schedule.
- Read the filter gauge; a jump over your clean number means it is time to clean.
- Test chlorine and pH with a home kit before anyone swims.
Testing the water after a storm
The CDC recommends at least 1 part per million of free chlorine in a home pool and a pH between 7.0 and 7.8. After a dust storm, test before anyone swims, and test again the next day, since debris left in the water keeps using up chlorine. Brushing the walls and floor and letting the filter run helps clear fine dust that has settled.
If the reading is off, follow the product labels exactly. Never mix pool chemicals with each other, store them apart in a dry, shaded place out of children's reach, and leave acid work to a professional. The CDC warns that mixing chlorine products with acid can release toxic gas.
Lightning and water do not mix. The National Weather Service says lightning can strike 10 miles or more from a storm, so if you can hear thunder you are close enough to be struck. Get everyone out of the pool and indoors right away, and wait 30 minutes after the last rumble before going back out. Rain stopping is not the signal; trailing clouds can still produce lightning.
Filters and pumps after the monsoon
A single dust storm can move a filter's pressure a long way. If the gauge reads about 8 to 10 psi over its clean number, the filter is due, even if it was cleaned recently. The guide to how often to clean a pool filter explains the pressure rule and a seasonal schedule, and the pool filter cleaning page covers what a professional clean involves for cartridge, DE and sand filters.
Pumps take a beating too. A basket packed with leaves starves the pump of water, which can make it run hot, lose prime or pull air. A pump that hums but does not spin, screeches, or will not come back on after an outage needs a technician, and the pool pump repair page explains what can fail. If a breaker or GFCI has tripped, you can reset it once. If it trips again, stop and call; do not keep resetting it, and never work on wet equipment.
When a storm leaves a green pool
If the power was out for a long time, or the pool was already low on chlorine when the dust arrived, the water can turn green within days of a summer storm. A green pool is a drowning hazard because nobody can see the bottom or someone who has slipped under. Keep children away from it, keep gates closed and latched, and never leave a child alone near the water.
Standing green water can also breed mosquitoes. Maricopa County Environmental Services takes mosquito and green pool complaints at 602-506-6616, and its Vector Control Division investigates them. The green pool cleanup page and the guide to why pools turn green explain the recovery.
When to call a pool company
- The water is cloudy or green a day after you skimmed, brushed and ran the filter.
- The filter pressure stays high after cleaning, or you are not comfortable opening it.
- The pump will not start, hums, leaks or trips the breaker a second time.
- The heater, salt cell, lights or automation stopped working after a power outage.
- A tree limb, fence panel or debris damaged the pool, tile or equipment.
Cleaning up after a storm is routine service. Replacing damaged equipment or plumbing is repair work, so ask the company for its license number first.
Check the license first. Arizona's Registrar of Contractors (ROC) licenses contractors, and its residential classifications include R-6, Swimming Pool Service and Repair. Repairs, equipment replacement and resurfacing generally call for a licensed contractor; whether a cleaning-only service needs a license is not spelled out, so ask the ROC if it matters to you. Ask the company for its ROC license number and look it up on the ROC contractor search (opens in a new tab) before work begins. The line does not check this for you.
On the road when a dust storm hits
If you are driving home to check on the pool when a haboob arrives, the Arizona Department of Transportation's advice is "Pull Aside, Stay Alive": pull completely off the pavement as soon as you can, turn off all lights, set the parking brake, take your foot off the brake and stay buckled in until it passes. The pool can wait.
Storm left a mess? Call any hour, say what you are seeing in the water and at the equipment, and you will be put through to a local pool company.
- Call the numberAn automated assistant answers (623) 240-0428 day or night, weekends included.
- Describe the poolSay what is going on: cloudy or green water, a pump that hums, a heater that will not fire, scale on the tile, and which part of the Valley you are in.
- Get put throughThe call is transferred to an independent, locally owned pool service company, which hears a short summary of the problem before it picks up.
- Deal with them directlyThat company looks at the pool, quotes, does the work and bills you. If it cannot answer, your name, number, area and problem are passed along so it can call you back.
About this line: Phoenix Pool Cleaning Pro is a free phone line, not a pool company. It answers your call and connects you with an independent local pool service company, which inspects, quotes and does the work, and which you pay directly. Companies may pay a referral fee. You never pay the line. See how the line works.