Fall Sprinkler Schedule: How Much to Cut Back Your Summer Timer, Month by Month

For a lot of sprinkler systems, the most wasteful stretch of the year is not July. It is fall. In July the timer is at least set for the weather it runs in. By October the weather is pulling about half as much water out of the yard, and by November about a third, yet the controller is still running the schedule someone set before the Fourth of July. A water-district study in Irvine, California described the pattern exactly: over-irrigation was "most prevalent in the fall months of September, October and November when ET rates are falling and summer irrigation schedules have not been revised" (Irvine Ranch Water District et al., 2001).

A good fall sprinkler schedule is not a new schedule. It is your summer schedule with fewer watering days, re-checked every month until winter. This guide explains why plants drink less after summer, why the soil empties more slowly (which is why you cut days, not minutes), how to work out your own cutback from local evapotranspiration data, a month-by-month plan with the official winter rules in Nevada and Florida and Arizona's desert watering guidelines, the mistakes that waste the most water in fall, and where to set a soil moisture sensor so the schedule adjusts itself.

Part 1: The biology — why your yard needs less water after summer

A lawn's daily water use is the weather's demand multiplied by a plant factor. FAO Irrigation and Drainage Paper 56 (Allen, Pereira, Raes and Smith, 1998), the reference method irrigation scientists use, writes it as crop evapotranspiration = Kc × ETo. ETo is the water a well-watered reference grass would lose under that day's sun, temperature, humidity and wind; Kc is the crop coefficient, which FAO sets at 0.90–0.95 for cool-season turf and 0.80–0.85 for warm-season turf (FAO-56, Table 12). In fall the sun is lower, the days are shorter and the air is cooler, so ETo drops week by week, and lawn water use drops with it.

Warm-season grasses (bermudagrass, St. Augustinegrass, zoysiagrass) also slow down as the soil cools. UC Cooperative Extension notes that "all bermudagrasses enter a dormancy period if grown where winter soil temperatures drop below 50 - 55°F" (Harivandi, California Turfgrass Culture). University of California turf coefficients reflect the slowdown: the monthly Kc for warm-season turf falls from 0.62 in September to 0.54 in October, against a year-round average of 0.60; cool-season turf averages 0.80 (UC ANR, after Meyer et al.).

Cool-season grasses (tall fescue, Kentucky bluegrass, perennial ryegrass) do the opposite underground. Penn State Extension notes that "root growth is greatest for cool-season grasses during spring and fall," with the best root growth at soil temperatures between 50°F and 65°F (Landschoot, Penn State Extension). They still need steady moisture in fall. They just use less of it per day, because the weather is asking for less.

Either way, the decline is steep. Across eight California and Texas locations, average October ETo is 46–66% of July's, and November's is 22–44%.

Part 2: The soil physics — same tank, slower drain

Think of the root zone as a tank. FAO-56 calls the water held between field capacity and the wilting point the total available water (TAW), and the share plants can use before they feel stress the readily available water: RAW = p × TAW. For turf, p is 0.40 for cool-season grass and 0.50 for warm-season grass (FAO-56, Table 22).

How big is the tank? University of Minnesota Extension, using the USDA NRCS irrigation guide, lists available water at 0.16–0.18 inch per inch of soil for loam, 0.11–0.13 for sandy loam and 0.14–0.16 for clay (UMN Extension). Take a lawn watered to a depth of 6 inches in loam: that layer holds about 1 inch of available water, and about half an inch of that is the refill you put back each time you water.

Here is the key point: in fall the tank does not shrink. It drains more slowly. So each watering should still put back about the same half inch. What changes is how many days it takes to use it up. University of Florida turf specialists put it in one line: "The amount applied should not be adjusted—only the frequency" (Trenholm et al., UF/IFAS). FAO-56 even allows a little deeper drying when demand is low: p rises by 0.04 for every millimeter per day that crop water use falls below 5 mm (Table 22 notes). At a fall demand of 2 mm per day, warm-season turf's p is about 0.62.

Cutting minutes instead of days does the opposite of what you want. Each run wets a shallower layer, roots stay near the surface, and the lawn surface still gets wet as often as it did in summer while drying more slowly in cool weather.

Part 3: The practical math — work out your own fall cutback

This is not a rounding error. In a 30-month Central Florida study, homes with homeowner-set timers applied 2.4 times the calculated irrigation requirement, and simply programming timers to a historical-ET schedule cut irrigation by 30% (Haley, Dukes and Miller, 2007, Journal of Irrigation and Drainage Engineering 133(5)). In a later trial during a dry period in Southwest Florida, weather-based controllers averaged 43% savings over a fixed timer without a rain sensor, with the biggest gap, 60%, in winter (Davis, Dukes and Miller, 2009, Agricultural Water Management 96(12)). Three steps get you most of the way there.

Step 1: Look up your local ETo by month

California's CIMIS reference ET zones and the TexasET Network's average ETo table publish long-term monthly averages; in Arizona, AZMET's ET tools total any month for your nearest station. Divide each fall month by July. Florida is different (see below the table).

Location (source)	July	Sept	Oct	Nov	Dec	Oct, % of July	Nov, % of July
Los Angeles Basin, Riverside (CIMIS zone 6)	6.51	4.80	3.72	2.40	1.86	57%	37%
San Bernardino (CIMIS zone 9)	7.44	5.70	4.03	2.70	1.86	54%	36%
Sacramento (CIMIS zone 14)	8.68	5.70	4.03	2.10	1.55	46%	24%
Fresno (CIMIS zone 12)	8.06	5.40	3.72	1.80	0.93	46%	22%
Indio, El Centro (CIMIS zone 18)	9.61	6.90	4.96	3.00	2.17	52%	31%
Dallas–Fort Worth (TexasET)	7.40	5.49	4.19	2.59	2.10	57%	35%
Austin (TexasET)	7.22	5.57	4.38	2.74	2.21	61%	38%
Houston (TexasET)	6.52	5.57	4.28	2.90	2.35	66%	44%

Values are average monthly reference evapotranspiration in inches, from California DWR's CIMIS reference ET zones and Texas A&M AgriLife's average ETo tables. Florida works differently, because the summer rainy season does much of the watering: UF/IFAS puts Orlando's average net irrigation requirement at 4.8 inches in May, 1.7 in July, 2.0 in October, 1.5 in November and 0.7 in December (Romero, Cardenas and Dukes, AE482). Florida's heaviest schedule belongs in spring, and its fall cutback starts in November, not October.

Step 2: Turn ETo into days between waterings

Days between waterings = refill amount ÷ daily lawn use, and daily lawn use = monthly ETo ÷ days in the month × turf coefficient. Take a Dallas bermudagrass lawn on loam, with a half-inch refill and UC's warm-season coefficient of 0.6:

• July: 7.40 ÷ 31 × 0.6 = 0.14 inch a day. Water about every 3–4 days.
• October: 4.19 ÷ 31 × 0.6 = 0.08 inch a day. About every 6 days.
• November: 2.59 ÷ 30 × 0.6 = 0.05 inch a day. About every 10 days.
• December: 2.10 ÷ 31 × 0.6 = 0.04 inch a day. About every 12 days.

Those are dry-weather numbers. Every soaking rain resets the count, and a dormant lawn uses less than the coefficient suggests.

Step 3: Keep the minutes, change the days

Run the catch-cup test once to learn how many minutes each zone needs to put down about half an inch. Keep those minutes. Then cut watering days: in the Dallas example, from two days a week in July to one in October, and to an every-10-days interval in November if your controller has an interval setting. Many controllers also offer a "seasonal adjust" percentage. It is quick, but it scales the minutes, which makes every run shallower. Cut days first.

Part 4: A month-by-month fall and winter schedule

EPA WaterSense keeps it simple: "Irrigation schedules should be adjusted based on seasonal changes" (EPA WaterSense). Here is what that looks like in practice.

• September: ETo in the table above is still 66–85% of July. If you water three or more days a week, drop one. In cold-winter states, keep cool-season lawns watered through September; it is root-building season (see our fall lawn watering guide for when to stop before the freeze).
• October: About half of July. Cut watering days roughly in half. Arizona's desert guide (2005 edition) suggests watering warm-season grass every 6–21 days from October to December, compared with every 3–6 days in summer, and desert-adapted shrubs every 14–30 days.
• November: About a third of July, and the month winter rules start. Daylight saving time ends at 2 a.m. on Sunday, November 1, 2026 (NIST), and Florida's water districts use the clock change as a reminder: the Southwest Florida Water Management District asks residents to "check the timers on their irrigation system controllers" when they fall back (SWFWMD, 2025).
• December to February: Warm-season lawns are dormant or close to it. Arizona's guide suggests warm-season grass every 15–30 days from December to March (overseeded ryegrass every 7–14 days), and UF/IFAS cites one irrigation every 10–14 days for Florida lawns in winter (Dukes and Cardenas, AE436). Where the ground freezes, the season ends with a shutdown and winterization instead.

Some places put the cutback in writing:

Area	Fall	Winter	Source
Las Vegas Valley	3 assigned days a week, Sept. 1–Oct. 31	1 assigned day a week, Nov. 1–Feb. 28	Southern Nevada Water Authority
Northeast and central Florida (standard rule)	2 days a week during daylight saving time	1 day a week from the first Sunday in November; never 10 a.m.–4 p.m.	St. Johns River WMD
Most of Southwest Florida	1 day a week under a water shortage order	1 day a week, through March 31, 2027	Southwest Florida WMD
South Florida	2 or 3 days a week, by area	Same, year-round; never 10 a.m.–4 p.m.	South Florida WMD
Arizona desert (guideline)	Warm-season grass every 6–21 days (Oct.–Dec.)	Every 15–30 days (Dec.–Mar.)	Landscape Watering by the Numbers, 2005 ed.

Two notes. In six northeast Florida counties and parts of five more, a Phase III water shortage order already limits lawns to one day a week all year and bans irrigation from 8 a.m. to 6 p.m. And Water – Use It Wisely released an updated edition of the Arizona guide in June 2026; check it for current intervals. Every rule here is a maximum, not a target. If the soil is still moist on your day, skip it.

Part 5: Common fall watering mistakes

1. Cutting minutes instead of days. Shorter runs wet a shallower layer of soil, so roots stay shallow while the surface still gets wet every few days. UF/IFAS's rule is to change the frequency and keep the amount.
2. Adjusting once and forgetting it. ETo keeps falling after the first change. In Sacramento, October's ETo is 46% of July's and November's is 24%, so an October schedule left alone applies almost twice what the lawn needs in November. Set-and-forget is common: in a Utah study of 376 accounts, about 57% of accounts with programmed sprinkler systems watered wastefully, compared with about 14% of accounts that watered mainly by hose (Endter-Wada et al., 2008, JAWRA 44(4)).
3. Watering through fall rain. Storms come back in fall, and a plain timer cannot tell. In University of Florida plot trials during normal wet weather, three of four soil moisture sensor brands cut irrigation 69–92% compared with a timer without a rain sensor, and a rain sensor alone cut it 34% (Dukes, Cardenas-Lailhacar and Miller, 2008).
4. Watering dormant grass as if it were growing. Once soil temperatures drop below 50–55°F, bermudagrass is dormant and uses little water. It still needs an occasional drink in a dry winter, at the long intervals above, not a weekly schedule.
5. Cutting cool-season lawns off too early. Fall is when tall fescue and bluegrass grow roots. Keep refilling the root zone; just do it less often.
6. One schedule for every zone. Shade, clay and drip-watered shrub beds dry far more slowly than a sunny lawn. Arizona's guide puts desert-adapted shrubs at every 14–30 days in fall and every 30–45 days in winter.

Part 6: Sensor placement and fall thresholds

A soil moisture sensor turns the math above into a reading. Put one in each zone you want it to control, in a spot that represents the zone: away from sprinkler heads, pavement edges and tree trunks (our sensor placement guide covers the details). The Soildrops sensor's listed measurement depth is 6 inches into the soil.

Then use two numbers: water when the reading falls to your trigger, and stop near field capacity. For loam, field capacity is about 27% volumetric water content, and the trigger is about 21% for cool-season grass (40% depletion) or 20% for warm-season grass (50% depletion). Sandy loam runs about 21% at field capacity with triggers of 16% and 15%, and clay about 40% with triggers of 33% and 31%; the full table is in our guide to field capacity and wilting point. In fall, FAO's adjustment lets a warm-season loam lawn drift to about 18% before watering.

You do not have to recalculate any of this by hand. The Soildrops app shows live soil moisture for free. With Autopilot (a paid plan: 30-day free trial, then $59.99 a year), the controller schedules from your soil moisture sensors and local weather, so the gap between waterings stretches on its own as fall demand drops. The 8-zone smart controller and starter kits replace a standard 24-volt timer using the existing valve wires.

Frequently asked questions

How much should I cut back my sprinklers in fall?

By about as much as your local evapotranspiration falls. In the California and Texas locations above, October averages 46–66% of July and November 22–44%. A practical rule: about half of your July watering in October and about a third in November, then less as warm-season grass goes dormant. Florida is the exception: its rainy season covers summer, so the cutback starts in November.

Should I water less often or for a shorter time?

Less often. Keep each run long enough to refill the root zone, usually about half an inch, and add days between runs. University of Florida guidance is to adjust frequency, not amount.

How often should I water my lawn in October?

In warm, dry climates, often about once a week. The Dallas example works out to every 6 days, and Arizona's guide suggests every 6–21 days for warm-season grass from October to December. Cool-season lawns in cold-winter states still need regular deep watering through mid-fall, while their roots are growing, but less than in summer.

When should I switch to a winter schedule?

When your local rules or your grass say so. The Las Vegas Valley switches on November 1. Northeast and central Florida's standard rule switches when clocks fall back, on November 1 this year. Bermudagrass goes dormant once soil temperatures stay below about 50–55°F.

Do I need to touch my timer when the clocks change?

Check it. A controller that does not set its own clock will run an hour off, which can push runs into restricted hours. Since you are in the settings anyway, that is the moment to drop to your winter watering days.

Does a dormant lawn need any water in winter?

A little, in dry spells. Arizona's guide suggests every 15–30 days for dormant warm-season grass, and UF/IFAS cites every 10–14 days for Florida lawns in winter. In freezing climates, winterize the system and hand-water only during long dry, unfrozen stretches.

The bottom line

Your lawn's water use falls fast after summer: about half of July's by October and about a third by November across much of California and Texas. Your soil holds the same amount of water in every season, so the fix is to keep each run deep and add days between runs, then tighten again in November, when daylight saving time ends and winter watering rules begin in places like Las Vegas and the parts of northeast and central Florida on the St. Johns River district's standard rule.

The audit you can do today: open your controller and write down each zone's watering days and minutes. Look up this month's ETo for your area, divide by July's, and multiply your watering days by that ratio (0.5 means half as many days). Then set two reminders, November 1 and December 1, to do it again.

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About this article. Researched and written by the Soildrops content team, drawing on FAO Irrigation and Drainage Paper 56, the California Department of Water Resources' CIMIS network, Texas A&M AgriLife's TexasET Network, University of Florida IFAS Extension, UC Cooperative Extension, Penn State Extension, University of Minnesota Extension, the Southern Nevada Water Authority, the St. Johns River, Southwest Florida and South Florida water management districts, the Arizona desert guide Landscape Watering by the Numbers, EPA WaterSense, NIST, the Irvine Ranch Water District's ET controller study, and peer-reviewed research in the Journal of Irrigation and Drainage Engineering, Agricultural Water Management and the Journal of the American Water Resources Association. All scientific claims are linked to original sources. Last updated October 2026.