Pool closing · Texas
When to Close Your Pool in Sherman, TX: Deadline, Window & Checklist
Last updated: July 15, 2026 · Model window year: 2026 · dates · checklist · FAQ
Circle November 5 on the Sherman 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 November 19. The window opens October 26 — the live widget below shows how this year is actually tracking against it.
Sherman closing dates at a glance
| Closing window | October 26 – November 5 |
|---|---|
| Close by (deadline) | November 5 |
| First freeze, 50% probability | November 19 |
| Open by (recommended) | March 25 |
| Opening window | March 18 – April 8 |
| 61°F crossing (7-day mean) | April 8 |
| Swim-season length (80°F+ days) | 140 days |
| NOAA normals station | Sherman · 5.3 mi · 760 ft |
Sherman's 140-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 Sherman's year in the model: mid-April at about 61°F, mid-June at 78°F, mid-August near the 84°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 Sherman winterizing checklist
A closing is a plumbing project with a chemistry warm-up. Start a few days ahead of your target date, keep every dose per its product label, and don't skip the photographs — spring-you reassembles from them.
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Balance the water a few days ahead
Start midweek for a weekend close: bring alkalinity and pH into their label ranges and let the water settle. What you seal under the cover is what the pool soaks in until spring.
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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
One final filter service per the manual — cartridges rinsed and stored dry indoors, sand or DE backwashed. Winter turns trapped gunk into concrete.
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Apply winter chemicals per label
Add a winterizing kit or your usual closing chemicals exactly as their labels direct for your volume, with the pump still circulating so everything distributes before shutdown.
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Lower the water level
Your cover's manual sets the number — commonly a few inches under the skimmer for solid covers, barely below normal for mesh. Stop there. The remaining water isn't laziness; it's ballast holding the shell in the ground.
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Blow out the lines and plug returns
Push air through skimmer, return, and cleaner lines until they run dry mist, then seat expansion plugs at each return while air still flows. This is the single most important freeze-protection step.
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Protect the skimmer
Give the skimmer something cheap to break: a guard bottle or rated plug absorbs the ice expansion that would otherwise split the housing.
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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
Open every drain plug on the pump, filter, heater, and chlorinator, and store the plugs in the pump basket so spring reassembly is a one-stop hunt. Move what you can indoors.
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Set the air pillow and cover
Pillow first, cover second, tension last. A properly centered pillow turns the winter ice sheet from a wall-pressing ram into a harmless dome.
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Store chemicals properly
Seal opened containers, keep oxidizers and acids separated, and store everything cool, dry, and locked away from kids and pets — exactly as each label describes.
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Calendar the off-season checks
Set a monthly reminder from November 5 to spring: check cover tension, pump off standing water, and glance at the water level. Fifteen minutes a month protects the whole closing job.
What to buy before the rush
The October crowd empties shelves in a predictable order. This is the short list worth owning before Sherman's window opens — nothing exotic, just the stuff everyone needs the same weekend.
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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
Closing chemistry in one box, dosed by pool volume.
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Air pillow
A soft target for the ice sheet, centered under the cover.
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Winter cover
Measure with overlap; the winter workhorse over everything else.
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Cover pump
Keeps rain and melt off a solid cover all season.
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Expansion plugs + skimmer guard
The blowout's finishing move — one per return, one for the skimmer.
How Sherman compares locally
Sherman closes in the latest quarter of Texas's calendar. Neighbors run close: McKinney (30 mi away) models its deadline at November 8 (3 days later vs Sherman's November 5), while Frisco (35 mi) shows November 9. The spring mirror of this page is the Sherman opening guide, and the season overview draws both windows on a single bar.
The measuring stick here is Sherman — 5.3 miles to the north, elevation about 760 feet. Its 1991–2020 record is what the model reads for Sherman; your backyard in Grayson County will run a touch warmer or cooler with shade, wind, and pavement, which is exactly the slack the two-week lead absorbs.
Field notes for Sherman owners
The skimmer is the most breakable part you own
Skimmer bodies crack because water freezes inside the throat with nowhere to push. A sacrificial bottle or spring-loaded guard absorbs that expansion for a few dollars. It's the highest-return item in the entire closing kit relative to what it protects.
What comes indoors
Cartridges, the cover pump when idle, chemical containers, and anything with a small motor overwinter better in the garage. Cold cycling is hard on plastics and seals; shelf space is cheaper than replacements. Label a single bin now and spring assembly becomes a scavenger hunt with a map.
The warm spell after you closed
A 78°F week in October doesn't mean reopening. Water under an opaque cover warms far less than air suggests, and a closed, balanced pool tolerates a warm stretch fine. Check the cover pump has somewhere to send rain, enjoy the weather, and leave the plumbing sealed.
Sherman pool closing FAQ
What temperature should water be to close a pool?
Close once water holds below about 65°F — the point where algae go mostly dormant — and before hard freezes. In Sherman, the 7-day mean drops through the threshold around October 26, so the window between then and November 5 is the sweet spot for a clean, stable close.
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. Sherman's water isn't reliably out of that zone until about October 26 — the calendar's first cold weekend doesn't change that.
Do I need antifreeze in pool lines?
Blown-out, plugged lines don't need it; doubtful lines do. Use only antifreeze labeled for pools, at the label's rate per foot of pipe — never automotive antifreeze. In Sherman the freeze clock starts around November 19, so settle this during closing, not during the first cold snap.
How far should I drain my pool for winter?
Only to the line your cover manufacturer prints — a few inches below the skimmer for most solid covers, close to operating level for many mesh designs with the skimmer plugged. The water you leave in is structural: it holds the shell against groundwater all winter.
What happens if you don't winterize a pool?
Expect equipment damage first — cracked pump volutes, split filter tanks, ruptured heater exchangers — then plumbing leaks that surface at startup. In Sherman, normals put the first freeze near November 19; everything after that date is borrowed time for an unwinterized system.
When is the last safe date to close in Sherman?
The model draws the line at November 5 for Sherman. It isn't arbitrary: the cool-down plus ten days (the freeze normal, November 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 Sherman hits the closing window
Data: NOAA 1991–2020 climate normals via Sherman (5.3 mi); live outlook by Open-Meteo. Full attribution on the sources page. Model assumptions and error bars on methodology.