Pool closing · Texas
When to Close Your Pool in Pasadena, TX: Deadline, Window & Checklist
Last updated: July 15, 2026 · Model window year: 2026 · dates · checklist · FAQ
Plan to close your Pasadena pool by December 3. The local 7-day mean temperature drops out of the algae-risk zone around November 23, and NOAA normals put the first 32°F freeze near December 28 — winterize between those dates and the water goes under the cover cold, clean, and easy to reopen. Below: today's water estimate, the full closing window, and a step-by-step winterizing checklist.
Pasadena closing dates at a glance
| Closing window | November 23 – December 3 |
|---|---|
| Close by (deadline) | December 3 |
| First freeze, 50% probability | December 28 |
| Open by (recommended) | February 12 |
| Opening window | February 5 – February 26 |
| 61°F crossing (7-day mean) | February 26 |
| Swim-season length (80°F+ days) | 187 days |
| NOAA normals station | Houston Hobby Airport · 8.0 mi · 44 ft |
Closing is close to optional here — many Pasadena owners trade the cover for shorter pump hours and swim the shoulder seasons. If you do close, the late window above still applies.
Four water checkpoints anchor Pasadena's year in the model: mid-April at about 69°F, mid-June at 82°F, mid-August near the 85°F peak zone, and mid-October easing through 75°F. The dates in the table are where those numbers cross the thresholds that matter.
The 12-step Pasadena 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
Give the chemistry a head start — balance to label ranges several days out, while circulation can still mix corrections evenly. Closing-day dosing never distributes as well.
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Deep-clean the pool
Make the last cleaning the best one of the year: full skim, full brush, careful vacuum. Debris left behind steeps all winter and greets you as April's water problem.
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Service the filter one last time
Backwash sand or DE, or pull and rinse cartridges, per the manual. A filter stored dirty cakes over winter and starts spring half-clogged.
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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
Drop the level as your cover manufacturer specifies — typically below the skimmer mouth for solid covers. Never drain a pool fully; groundwater pressure can damage the shell.
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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
Install a skimmer guard bottle (or a plug rated for your skimmer) so ice that forms there crushes the sacrificial piece instead of cracking the skimmer body.
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Add pool antifreeze where blowouts fall short
If any line can't be verified dry, add pool-grade antifreeze per its label. Use only pool antifreeze — automotive products don't belong in pool plumbing.
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Drain the equipment
Every vessel on the pad — pump, filter, heater, chlorinator — gets its drain plugs pulled. Drop all the plugs in the pump basket; that's the one place everyone looks first in spring.
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Set the air pillow and cover
Inflate the pillow to about two-thirds, center it, then bring the cover over and secure it per its design. Under ice, that soft dome is the difference between inward compression and outward wall pressure.
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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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Stage the cover pump
Solid covers need drainage all winter: set a cover pump or siphon before the first storm, not after. Standing water strains seams and invites a mid-winter emergency.
What to buy before the rush
The November crowd empties shelves in a predictable order. This is the short list worth owning before Pasadena's window opens — nothing exotic, just the stuff everyone needs the same weekend.
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Pool antifreeze
Pool-rated glycol for the lines air couldn't clear.
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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
The one purchase every other closing step depends on.
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Cover pump
Solid covers collect rain all winter; this is the drainage plan.
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Expansion plugs + skimmer guard
The blowout's finishing move — one per return, one for the skimmer.
How Pasadena compares locally
Two nearby data points to triangulate with: League City, 12 miles from Pasadena, models its close at December 2 (1 day earlier); Pearland, 12 miles out, at December 4. Pasadena's own window ends December 3. For the other half of the calendar see when to open in Pasadena, or scan the full year on the season page.
Every number on this page traces to one instrument cluster: Houston Hobby Airport, 8.0 miles west of Pasadena's center at an elevation near 44 feet. NOAA computed its 1991–2020 normals from roughly three decades of daily readings — long enough that one strange spring in Harris County barely moves the dates.
Field notes for Pasadena owners
Match the drainage plan to the cover
Solid covers shed nothing — they need a cover pump staged before the first storm and checked after each one. Mesh covers drain themselves but pass silt that settles all winter. Either way, the plan is decided in October, not improvised in January when the cover is an ice sheet.
Gas heaters get the manual, not a guess
Every heater brand sequences its winterizing differently — drain plugs, blower considerations, gas supply, control settings. The generic advice (drain fully, close the valve) is right but incomplete; ten minutes with your model's manual protects the most expensive component you'll winterize.
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 case for a shorter off-season
Pasadena's climate leaves water usable well past most owners' patience. If the family still swims in December, don't rush the cover — the model window runs to December 3 for a reason. Closing late and cold beats closing early and warm in every spring-condition metric that matters.
Pasadena pool closing FAQ
What temperature should water be to close a pool?
Cold enough that biology has clocked out — below 65°F and falling, ideally low 60s. The widget above tracks Pasadena's actual water; the normals say the durable cool-down arrives near November 23, and anything inside the window to December 3 closes clean.
Can you close a pool too early?
Yes — it's the most common closing mistake. Seal 70°F water under a cover and algae keep growing in the dark all autumn; the spring opening turns green and expensive. In Pasadena, hold off until the cool-down near November 23 before covering.
Do I need antifreeze in pool lines?
Only where water might remain. If every line is properly blown out and plugged, air is the antifreeze. Lines you can't verify dry — long runs, low spots, water features — get pool-grade antifreeze dosed per its label. With Pasadena's first freeze normal near December 28, don't leave that question open.
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?
The freeze finds every shortcut. Ice in an unprotected pump or heater cracks castings from the inside; ice in underground lines splits fittings you can't see until spring. Pasadena reaches freeze territory around December 28 — the checklist above is cheaper than any one of those repairs.
When is the last safe date to close in Pasadena?
Treat December 3 as the deadline in Pasadena. It's derived from the 1991–2020 normals: the cool-down plus ten days (the freeze normal, December 28, leaves room to spare). Weather varies year to year, so watch the 10-day forecast in late December — an early cold snap moves the real deadline, and the widget above flags exactly that.
Email me when Pasadena hits the closing window
Data: NOAA 1991–2020 climate normals via Houston Hobby Airport (8.0 mi); live outlook by Open-Meteo. Full attribution on the sources page. Model assumptions and error bars on methodology.