When should I open my pool in Nassau/Suffolk County?

Most Long Island pools open between mid-April and Memorial Day weekend. The decision driver is air temperature: once daytime highs are consistently in the 60s and nighttime lows stay above freezing, it's safe to open. Opening too late (after water temps hit ~65°F under the cover) allows algae to bloom, making the opening more expensive.

Popular service companies book up fast — the two weeks before Memorial Day are the busiest of the year. If you want a specific opening date, call your company in March.

Rule of thumb: open 2–3 weeks before you actually want to swim. Water needs time to heat and chemistry needs time to balance.