Pool opening · Washington
When to Open Your Pool in Redmond, WA: Best Dates & Checklist
Last updated: July 15, 2026 · Model window year: 2026 · dates · checklist · FAQ
Plan to open your pool in Redmond by May 31. Our model of NOAA 1991–2020 normals puts the local 7-day mean temperature at the algae-growth threshold around June 14 — and pool stores hit their May rush weeks later. Below: today's estimated water temperature, the full opening window, and a step-by-step checklist with what to buy before shelves empty.
Redmond opening dates at a glance
| Open by (recommended) | May 31 |
|---|---|
| Opening window | May 24 – June 14 |
| 61°F crossing (7-day mean) | June 14 |
| Closing window | September 21 – October 1 |
| Close by (deadline) | October 1 |
| First freeze, 50% probability | November 23 |
| Swim-season length (80°F+ days) | 0 days |
| NOAA normals station | Seattle Sand Pt WSFO · 6.5 mi · 60 ft |
A short season cuts both ways: every week opened before June 14 is a real slice of Redmond's roughly 0-day warm-swim budget.
The same model in water terms: Redmond's estimated pool temperature runs about 50°F in mid-April, 60°F in mid-June, 68°F in mid-August, and 56°F in mid-October, peaking near 68°F. Those four checkpoints — not any calendar holiday — are what the windows above are protecting.
The 12-step Redmond opening checklist
Built for Redmond's window: physical teardown first, a full day of circulation, then chemistry per each product's label. Nothing here requires a pro, but step 1 goes easier with a second pair of hands.
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Pump off and clear the winter cover
Drain standing water with a cover pump, sweep off debris, then drag the cover clear without dumping the muck into the pool. Working backward from May 31 means doing this while mornings are still cool.
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Top up the water level
Set the garden hose in and bring the level to the skimmer's midpoint. That height is what lets the skimmer pull a proper surface current once the pump starts.
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Remove winter plugs and reinstall fittings
Trade out the winter hardware: expansion plugs and skimmer guard out, eyeball fittings and baskets back in, ladders and rails re-seated. Feel each o-ring as you go — brittleness now means an air leak by July.
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Reassemble the equipment pad
Reinstall drain plugs on the pump, filter, and heater; lube o-rings with the manufacturer-recommended lubricant; reconnect unions hand-tight plus a quarter turn.
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Prime the pump and run for 24 hours
Fill the pump basket housing with water, open air relief on the filter, and start the system. Let it run a full day to turn the water over several times before you judge clarity.
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Service the filter
The filter starts the season clean or the season starts badly: rinse or swap cartridges, backwash sand, recharge DE — whichever your manual prescribes.
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Brush, skim, and vacuum
Brush walls and steps, skim the surface, and vacuum settled debris to waste if your plumbing allows. Mechanical cleaning removes the organic load chemicals would otherwise burn through.
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Test the water
Get a real baseline before spending a dollar on chemicals: full-panel test with fresh reagents. Winter reliably moves pH, alkalinity, and stabilizer, and guessing at any of them costs more than the strips do.
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Balance, then shock — per product labels
Correct total alkalinity before pH — it's the stabilizer of the pair — dosing exactly what each label specifies for your volume. Then shock per its label and let the pump run through the night.
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Filter until the water clears
From here it's cycles: run the filter long, test daily, top up doses only as labels direct, and wait for the floor to come into focus. Resist the urge to dump in more chemistry — clarity is mostly filtration.
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Set the timer for spring runtime
Program the pump for roughly one full turnover a day to start — cool spring water in Redmond forgives shorter runtimes, and you can stretch hours as air temperatures climb toward summer.
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Photograph the pad and plumb lines
Take phone photos of valve positions, plumbing runs, and the equipment pad while everything is fresh. Fall-you, holding a blowout adapter, will be grateful for the reference set.
What to buy before the rush
A small stack of supplies turns the checklist above into a single-weekend job. Buy before Redmond's June rush and the whole list ships at leisure instead of sprinting.
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Leaf net + wall brush
Wall brush plus deep net — the manual half of every checklist.
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Robotic pool cleaner
The premium shortcut: set it in, plug in, come back to clean.
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Pool opening chemical kit
Skips five separate purchases; sized by gallons on the box.
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7-way test strips
The opening baseline: pH, alkalinity, hardness, stabilizer, chlorine in seconds.
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Start-up shock
Cold clean water plus one labeled dose beats a green recovery.
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Filter cartridge / DE refill
Start the season on fresh media; dirty filters stretch cloudy days.
How Redmond compares locally
Before booking a service slot, compare Redmond against its neighbors: Kirkland (4 mi) models to May 31, Bellevue (6 mi) to May 24, against Redmond's own May 31 — placing it in the later half statewide at the 62th percentile. When autumn planning starts, the closing checklist picks up where this page ends, and the Redmond pool season page holds the one-glance summary.
Local means local: Redmond's dates come from Seattle Sand Pt WSFO, the nearest station with complete daily temperature normals — 6.5 miles west, about 60 feet up. Between that station and a King County backyard there's always a degree or two of microclimate; the windows are built wide enough to carry it.
Field notes for Redmond owners
Stabilizer: the sunscreen your chlorine needs
Spring sun destroys unstabilized chlorine within hours, which reads as "the pool eats chlorine" when it's really UV. Test cyanuric acid at opening — winter rain and splash-out dilute it — and restore it per the product label before judging your sanitizer consumption.
Getting the cover off without seeding the pool
The debris field on top of a winter cover carries exactly the organic load your opening chemicals will otherwise fight. Pump the water off first, sweep while it's dry, and pull the cover in folds toward one end rather than dragging the whole sheet across the water. Two people and ten unhurried minutes beat one person and a spill every time.
The service-rush arithmetic
Pool service calendars fill in reverse: the crews that install liners and fix heaters in April are fully booked by the first hot weekend. Opening early means any problem you discover — a seeping seal, a dead capacitor — gets an appointment this month, not after Memorial Day. Weighing hired help against a Saturday? The service-vs-DIY guide breaks down what a visit includes.
Short-season strategy
Redmond gets about 0 days of 80°F-plus afternoons in the normals — a season measured in weekends. Opening by May 31 converts otherwise-lost spring weeks into usable shoulder season, and a solar cover stretches both ends. In short-summer country, the calendar is the most valuable pool equipment you own.
Redmond pool opening FAQ
What water temperature causes pool algae?
Algae growth accelerates once water passes roughly 65°F, and the 65–70°F band under a winter cover is where most green openings are born. Below about 60°F growth is slow. That's the whole logic of Redmond's window: our model has local water approaching that zone near June 14, so the pool should be open and circulating first.
What temperature should it be outside to open a pool?
Think in weekly averages, not single sunny days. Once the 7-day mean temperature reaches the low 60s°F — June 14 in Redmond, per NOAA normals — water warms into algae territory within days. A 70°F-afternoon stretch is the same signal read off a thermometer instead of a dataset.
Is it cheaper to open a pool early or late?
Run the two budgets side by side. Early (May 31-ish): some extra pump hours, one startup shock, done. Late: cover comes off green, and now it's repeat shock doses, clarifier, round-the-clock filtering, maybe a service call — plus peak-season prices on all of it. Early wins in Redmond every ordinary year.
How long after opening can you swim?
Once the water is clear enough to see the main drain, test readings sit inside the ranges printed on your product labels, and any shock's label re-entry conditions are met. After a clean Redmond opening that's often just a day or two of filtration; a green start can take a week or more.
What chemicals do I need to open a pool?
A test kit or strips, alkalinity and pH adjusters, calcium hardness increaser if your water runs soft, stabilizer (cyanuric acid), your regular sanitizer, and a startup shock. Buy before Redmond's rush around June 14, and dose everything strictly by each product's label for your pool volume — category-by-category buying notes live in the opening chemicals guide.
When do most people open pools in WA?
Nationally, early-to-mid May and the Memorial Day weekend dominate — which is why late openers meet empty shelves and week-long service waits. Our Washington model medians out at May 24 across 21 cities, and Redmond pencils in May 31, comfortably ahead of the rush.
Email me when Redmond hits the opening window
Data: NOAA 1991–2020 climate normals via Seattle Sand Pt WSFO (6.5 mi); live outlook by Open-Meteo. Full attribution on the sources page. Model assumptions and error bars on methodology.