Pool closing · California
When to Close Your Pool in Antioch, CA: Deadline, Window & Checklist
Last updated: July 15, 2026 · Model window year: 2026 · dates · checklist · FAQ
Circle November 10 on the Antioch calendar. Closing earlier traps warm, algae-friendly water under the cover; closing later gambles the plumbing against the first freeze, which the 1991–2020 normals place near December 19. The window opens October 31 — the live widget below shows how this year is actually tracking against it.
Antioch closing dates at a glance
| Closing window | October 31 – November 10 |
|---|---|
| Close by (deadline) | November 10 |
| First freeze, 50% probability | December 19 |
| Open by (recommended) | April 3 |
| Opening window | March 27 – April 17 |
| 61°F crossing (7-day mean) | April 17 |
| Swim-season length (80°F+ days) | 142 days |
| NOAA normals station | Antioch Pumping Plt #3 · 2.4 mi · 60 ft |
Antioch's 142-day warm season leaves comfortable margins on both ends — the windows above aim you at the cheap-chemistry versions of each transition.
Four water checkpoints anchor Antioch's year in the model: mid-April at about 60°F, mid-June at 72°F, mid-August near the 76°F peak zone, and mid-October easing through 68°F. The dates in the table are where those numbers cross the thresholds that matter.
The 12-step Antioch winterizing checklist
Sequenced against Antioch's October 31–November 10 window: chemistry while the pump still runs, blowouts before the equipment drains, cover last. Labels dictate every dose.
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Balance the water a few days ahead
Do the chemistry midweek, close on the weekend: alkalinity and pH into label ranges with days of circulation left to spread them. Winter locks in whatever state the water holds on closing day.
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Deep-clean the pool
Skim, brush walls and steps, and vacuum carefully. Any leaves or algae you seal under the cover become spring's chemistry problem, so closing day cleanliness pays twice.
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Service the filter one last time
Send the filter into winter clean: backwash the sand or DE, rinse and dry the cartridges indoors. Media stored dirty over winter hardens into a spring problem no backwash fixes.
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Apply winter chemicals per label
Dose the winter kit while the pump still runs — every product exactly per its label for your volume — so the chemistry is fully mixed before the system goes quiet.
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Lower the water level
Take the level down only as far as the cover's manual says — usually just below the skimmer for solid covers, higher for many mesh systems. An empty pool is never the goal; shells crack and shift without water's weight.
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Blow out the lines and plug returns
Work line by line: push air until the return spits dry mist, plug it against the flowing air, move on. Skimmer, returns, cleaner line, in whatever order your plumbing prefers — dry pipes are the entire point of closing.
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Protect the skimmer
The skimmer throat is where trapped water has no escape — park a guard bottle or rated plug in it and let ice crush the cheap part.
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Add pool antifreeze where blowouts fall short
Antifreeze is the insurance policy for doubtful lines, not a replacement for the blowout: pool-grade product, label dosing, and only where air couldn't finish the job.
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Drain the equipment
Nothing on the pad should hold water overnight: pull the drain plugs from pump, filter, heater, and feeder, stash them all in the pump basket, and carry the portable pieces indoors.
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Set the air pillow and cover
Center an inflated air pillow, then fit the cover and secure it with water bags, cable, or straps as designed. The pillow gives ice a place to push besides your walls.
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Calendar the off-season checks
Set a monthly reminder from November 10 to spring: check cover tension, pump off standing water, and glance at the water level. Fifteen minutes a month protects the whole closing job.
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Remove and store ladders and rails
Pull ladders, rails, and the diving-board hardware; rinse, dry, and store them out of the weather. Anchor sockets get a dab of protectant so spring bolts turn freely.
What to buy before the rush
A small stack of supplies turns the checklist above into a single-weekend job. Buy before Antioch's October rush and the whole list ships at leisure instead of sprinting.
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Cover pump
Standing water is a cover killer; this is the counter.
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Expansion plugs + skimmer guard
The blowout's finishing move — one per return, one for the skimmer.
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Pool antifreeze
For lines you can't verify dry — pool-grade only, per label.
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Winter closing kit
Season-length winter chemicals in one label-dosed box.
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Air pillow
A soft target for the ice sheet, centered under the cover.
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Winter cover
Sized to overlap; the cheapest insurance the pool wears all winter.
How Antioch compares locally
Statewide context: across the 147 California cities we model, Antioch's November 10 deadline sits in the later half. Nearby, Brentwood (5 mi) closes around November 10 and Pittsburg (6 mi) around November 10 — treat gaps under a week as microclimate noise, not strategy. Spring planning restarts at the opening guide; the Antioch pool season page keeps the whole year in one view.
The instrument behind this page is Antioch Pumping Plt #3, 2.4 miles east of Antioch — the closest station publishing complete 1991–2020 daily temperature normals. Thirty years of its readings set every date above; your own yard adds or subtracts a degree with shade, wind, and pavement, which is what the window's width is for.
Field notes for Antioch owners
Leaf season vs closing day
If your yard drops serious leaves, the cheap trick is a leaf net over the main cover through the drop, then one bulk removal before snow. Leaves that winter on (or worse, under) the cover steep like tea and hand you stained water and clogged pumps in spring.
Salt cells overwinter indoors
Remove the cell at closing, inspect and clean per the manufacturer, and store it inside with the unions capped. A dummy cell or spacer keeps the plumbing sealed. Cells left in outdoor plumbing through freezes are a common — and completely avoidable — spring casualty.
Blowout first, antifreeze second
Air is the only guaranteed freeze protection: a line that's verifiably dry cannot burst. Antifreeze (pool-grade, per label) is the fallback for lines you can't confirm — long runs, low spots, water-feature plumbing. Doing antifreeze instead of a blowout, rather than in addition, is how most cracked returns happen.
Antioch pool closing FAQ
What temperature should water be to close a pool?
Below roughly 65°F, and trending down. Water closed warm keeps feeding algae under the cover for weeks; water closed in the 50s goes dormant almost immediately. Antioch's cool-down lands near October 31 in the normals, which is why the window opens there.
Can you close a pool too early?
Early closing is the mistake the whole model is built to prevent from the other direction. A cover installed over 70°F water is a terrarium: sanitizer decays, algae compound, nobody looks for months. Antioch's water isn't reliably out of that zone until about October 31 — the calendar's first cold weekend doesn't change that.
Do I need antifreeze in pool lines?
It depends entirely on your confidence in the blowout. Lines that blew fully dry need nothing; anything uncertain — low runs, water features, a stubborn cleaner line — gets pool-grade antifreeze at the label's rate per foot. With Antioch's freeze clock starting near December 19, uncertainty is the thing to eliminate.
How far should I drain my pool for winter?
Follow the cover's instructions first: solid covers usually want water a few inches below the skimmer; some mesh setups run higher with the skimmer sealed. The hard rule is never empty — hydrostatic pressure can lift or crack an empty pool, a far worse outcome than any freeze.
What happens if you don't winterize a pool?
The repair list writes itself in order of cost: heater heat exchanger, pump housing, filter tank, then every fitting the ice reached — discovered one leak at a time in spring. Around Antioch the exposure begins near December 19, and each skipped checklist step above is one more candidate for that list.
When is the last safe date to close in Antioch?
The model draws the line at November 10 for Antioch. It isn't arbitrary: the cool-down plus ten days (the freeze normal, December 19, leaves room to spare), and the whole closing sequence needs a working weekend of margin. The one exception that overrides any date — a hard freeze inside the 10-day forecast, which the widget above flags as urgent.
Email me when Antioch hits the closing window
Data: NOAA 1991–2020 climate normals via Antioch Pumping Plt #3 (2.4 mi); live outlook by Open-Meteo. Full attribution on the sources page. Model assumptions and error bars on methodology.