Specialist answer // Arizona Watering & Seasons

How should irrigation be adjusted for Arizona monsoon season?

Adjusting your irrigation during the Arizona monsoon requires monitoring rainfall, utilizing rain sensors, and watering in the early morning to prevent fungal diseases.

Reviewed by Richard Mora, owner Updated Aug. 25, 2026 4 min. read

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Understanding Monsoon Moisture

The Arizona monsoon season brings intense heat, high humidity, and unpredictable rainfall that significantly impacts landscape water needs. During this time, the sudden influx of moisture can temporarily replace the need for supplemental irrigation, but the erratic nature of the storms means rainfall amounts vary widely even within the same neighborhood.[1]

While the increased humidity benefits many heat-tolerant plants, the combination of high temperatures and moisture also creates conditions favorable for fungal diseases if watering is not managed correctly. Therefore, adjusting irrigation schedules to match the actual rainfall received is crucial for maintaining plant health and conserving water resources.[2]

Adjusting Your Irrigation Controller

A key adjustment during the monsoon season is shifting watering times to the early morning, ideally between 4:00 AM and 8:00 AM. Watering in the evening or at night during high humidity periods can leave foliage wet for too long, increasing the risk of fungal infections.[2]

Additionally, homeowners must be vigilant about power disruptions caused by monsoon lightning storms. Electrical surges can reset older irrigation timers to default daily schedules, leading to severe overwatering. Checking the controller after a storm ensures the custom schedule remains intact and prevents unexpected water waste.[1]

Arizona Monsoon Watering Strategies

For Phoenix-metro homeowners, the most effective strategy during the monsoon is to closely monitor actual rainfall and adjust the irrigation controller accordingly. If a significant storm delivers rain to your property, manually turn off the irrigation system for a few days to allow the soil to absorb the moisture and prevent wasteful runoff.[1]

However, because monsoon storms can be followed by prolonged dry, hot spells, it is vital to resume regular watering once the soil dries out. Utilizing a smart weather-based irrigation controller or adding a simple rain sensor can automate this process, ensuring that plants receive water only when needed and protecting the system from running during a downpour.[3]

Safe first look

What a homeowner can check first.

These observations can make the service conversation clearer. Stop if water is uncontrolled, wiring is exposed, or the next step requires opening pressurized components.

Monitor local rainfall using a simple rain gauge

Manually turn off the irrigation controller when rain is forecasted or occurring

Check the controller display after power outages to ensure the schedule is intact

Inspect the yard for standing water that could breed mosquitoes

Add mulch around plants to retain moisture during extreme heat

Professional threshold

Call an irrigation specialist when:

Call (602) 905-4494

Irrigation timer sustains lightning damage and loses programming

System wiring faults occur after heavy monsoon flooding

Rain sensors fail to bypass scheduled watering during storms

Valve boxes fill with mud and valves fail to open or close

Need local service?Irrigation System Inspection in Scottsdale Irrigation System Inspection in Phoenix More arizona watering & seasons answers

Useful answers around this issue.

These answers provide general context. The actual cause still depends on the system and what happens when the affected zone is tested.

Should I prune my trees heavily before monsoon season?

No, heavy pruning exposes interior branches to sunburn and should be avoided unless removing storm-damaged limbs.

Can I rely entirely on monsoon rain for my plants?

No, monsoon rainfall is inconsistent, so supplemental irrigation is necessary during dry spells between storms.

What is the best time of day to water during the monsoon?

Early morning (4-8 AM) is best; high humidity combined with evening watering can encourage fungal diseases.

Sources and review

Where the technical guidance comes from.

This article was reviewed for service accuracy by Richard Mora. Sources are provided for factual context; product-specific instructions should still follow the installed manufacturer’s documentation.

[1]
Prepare your yard for the monsoon season to prevent damage and water wasteAMWUAOpen source
[2]
August Monthly Gardening Guide for Pima CountyUniversity of Arizona Cooperative ExtensionOpen source
[3]
Weather-Based Irrigation ControllersEPA WaterSenseOpen source

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Understanding Monsoon Moisture

Adjusting Your Irrigation Controller

Arizona Monsoon Watering Strategies

What a homeowner can check first.

Call an irrigation specialist when:

Useful answers around this issue.

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Where the technical guidance comes from.

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