Typical price of a professional sprinkler blowout in the US; most homes land near $85–$100, with roughly $7–$12 added per extra zone.
AngiWhen to Winterize Sprinklers in Colton, CA
SEASON PASSED174 days until first 28°F freezeJan 1
In a typical year, winterize your sprinkler system in Colton by December 22. The median first 28°F hard freeze at Colton's NOAA station is January 1 (1991–2020 normals); one year in ten it arrives as early as December 13. The early-odds date runs roughly 19 days ahead of the median, so build in that buffer.
Dec 22Local deadline
Jan 1Median first 28°F
62 days28°F window spread
Station 7.3 miSnow per season
OUTLOOK
Typical first first 28°F freeze near Jan 1; local deadline about Dec 22. The live 10-day outlook loads here.
Local freeze dates for Colton
| Threshold | Early (1-in-10) | Median | Late (9-in-10) |
|---|---|---|---|
| 32°F (light freeze) | Dec 1 | Dec 19 | Jan 26 |
| 28°F (hard freeze) | Dec 13 | Jan 1 | Feb 13 |
Bars span the early (1-in-10) to late (9-in-10) window for each freeze threshold; the dot marks the median year. The dashed line is the local prep deadline.
NOAA station: Redlands · 7.3 mi away · 1,410 ft elevation.
- Colton is on the early end of the national freeze calendar; plan as if fall cold arrives ahead of schedule.
- With about 62 days separating the early and late dates, watch the live outlook rather than banking on the median.
Colton draws its numbers from Redlands, 1,410 feet up and 7.3 miles away. Its median first-freeze dates are 32°F by Dec 19, 28°F by Jan 1. The 28°F freeze has come as early as Dec 13 and as late as Feb 13, a 62-day spread. Spring's last 32°F freeze clears around Jan 27.
In Colton, freezing nights (32°F) typically begin around Dec 19 and the first hard freeze (28°F) follows near Jan 1. The 32°F date swings from Dec 1 at its earliest to Jan 26 at its latest, near 56 days. The last spring freeze averages Jan 27 and as late as Feb 28, which sets the safe window for reopening outdoor water and de-winterizing gear. Snow barely registers here; the freeze date, around Jan 27, is the one that matters.
Your sprinklers checklist
- Shut off the irrigation water supply at the main valve and, if you have one, the dedicated sprinkler shutoff inside the house.
- Turn off the controller or set it to the "rain" mode so valves do not open while the system is dry.
- Drain the mainline using the manual, automatic, or blow-out method your system was built for; most pros prefer a blow-out.
- Connect a compressor to the blow-out port through a proper adapter and run 40–80 psi, one zone at a time, until the heads mist and clear.Helpful gear: Air compressor blow-out adapter — Recommended pick
- Insulate the backflow preventer and any above-ground valves; this brass assembly is usually the first part to crack.Helpful gear: Insulated backflow preventer cover — Recommended pick
- Cap outdoor hose bibs with foam covers after the hoses come off so the last exposed fittings stay protected.Helpful gear: Foam outdoor faucet covers — Recommended pick
- Open the backflow test cocks a quarter turn so any trapped water has room to expand.
- Log the date and the psi you used; you will want the reference next fall.
What to have on hand
As an Amazon Associate we may earn from qualifying purchases. Product picks are editorial; links do not change what you pay.
Air compressor blow-out adapter
Quick-connect fitting that mates a shop compressor to your irrigation line.
Recommended pickInsulated backflow preventer cover
Pouch that shields the above-ground backflow valve from early frost.
Recommended pickFoam outdoor faucet covers
Slip-on domes that protect hose bibs after you drain them.
Recommended pickPortable air compressor
A modest pancake unit moves enough air to clear most home zones.
Recommended pickSprinkler blowout cost & key numbers
Verified national benchmarks; sources open in a new tab (nofollow).
Maximum safe blow-out pressure for flexible polyethylene pipe (≤80 PSI for rigid PVC). Air volume does the real work — about 20–25 CFM clears a residential zone.
Colorado State University ExtensionReplacement cost of a freeze-cracked backflow preventer — the brass assembly cannot be repaired once ice splits the body, and freeze damage voids most device warranties.
PlumbingPriceGuideHow much water expands when it freezes — enough force inside a charged line to split fittings, valves and the backflow body over a single hard night.
EPA WaterSenseWhat this means locally
Colton freezes close to San Bernardino (Jan 1) and close to Highland (Jan 1) — a reminder that even nearby towns differ by days. Statewide, California prep dates run Jan 6 through Dec 27, which is why Colton gets its own number rather than a California-wide average. The same freeze also decides when to protect your indoor pipes and winterize an RV if you own one. Keeping an eye on the rest of the county? The same local math is on our Clovis and Concord pages.
Other winter jobs in Colton
Every task below is dated to Colton's own freeze and snow normals.
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Frequently asked questions
What temperature freezes sprinkler pipes?
Standing water in shallow lines and the backflow assembly can start to freeze once air temperatures drop into the mid-20s for several hours. Buried mains are slower, but the exposed brass backflow preventer and above-ground valves are the parts that crack first, which is why the deadline is tied to the first 28°F freeze, not the first frost.
Do I need to blow out my sprinklers or just drain them?
It depends on how the system was installed. Manual or automatic drains work if the lines were pitched to low points. Most irrigation pros recommend a compressed-air blow-out because it clears water that drains miss, especially in flat yards. If you are unsure how your system drains, a blow-out is the safer choice.
What happens if I don't winterize my sprinkler system?
Water left in the lines expands as it freezes and can split the backflow preventer, crack valves, or break fittings. Repairs to a backflow assembly commonly run more than the cost of a blow-out. The damage often is not visible until you turn the system on in spring and find leaks.
How much does a sprinkler blowout cost?
A professional blow-out typically costs somewhere in the range of a modest service call, depending on the number of zones and your region. Buying an adapter and using your own compressor costs less over time, but you need enough air volume to clear each zone. Prices rise once the first freeze warnings appear, so book early.
When should I turn my sprinklers back on in Colton?
Wait until the last spring freeze has passed, which averages around Jan 27 here in the 1991–2020 normals. Turning the system on too early risks refreezing a charged line. Open the main slowly to avoid a pressure surge, then walk each zone to check for winter damage before you rely on the schedule.
Can I winterize sprinklers myself?
Draining and insulating are within reach for most homeowners. A blow-out is doable if you own a compressor that moves enough air and you use a proper adapter, working one zone at a time at safe pressure. If your system lacks a clear blow-out port or you are not confident, hiring a pro once is a reasonable call.
How many PSI do I need to blow out my sprinkler system?
Use a regulated 40–60 PSI for most residential systems, and never exceed 50 PSI on flexible polyethylene pipe or 80 PSI on rigid PVC — more pressure can crack pipes and shred sprinkler seals. Air volume matters more than pressure: about 20–25 CFM moves the water out, while a small pancake compressor needs several short passes per zone.
Do I need to winterize the backflow preventer too?
Yes — it is the most expensive single component at risk. Drain it fully, leave the test cocks and ball valves at a 45° half-open angle for winter, and never force compressed air directly through a pressure vacuum breaker, which can destroy its internal seals. A freeze-cracked unit cannot be repaired and costs $200–$1,800 to replace.
Sprinkler Winterization: related searches
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Data: NOAA 1991–2020 normals via Redlands, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 25, 2026.