Haze, Thunderstorms and PSI: When Singapore Pools Actually Cancel Swimming Lessons

Every parent in Singapore has had the message. You are halfway to the pool, the sky has gone the colour of a bruise, and your phone buzzes: lesson cancelled. Or it is a clear day and the message comes anyway, because the air is thick with smoke from Sumatra.

Three different things stop a swimming lesson here, and three different people make the call. Here is who decides, when, and what happens to the lesson you paid for.

1. Thunderstorms: the pool operator decides, not the coach

Lightning is the most common reason a lesson stops in Singapore. Public pools, ActiveSG included, clear the water when there is lightning risk in the area and usually keep it closed until about 30 minutes after the last thunder. That call belongs to the venue, not to the swimming school.

This is why a lesson is not cancelled just because the weather app shows a storm icon. Our admin confirms with the venue or the coach on deck first. A storm that passes quickly can mean a shortened lesson rather than none, so if you are already nearby, wait for the message before turning around.

When the pool is closed on lightning, the session is logged as a school-side cancellation. It is credited back to you and never counts against your makeup allowance.

2. Haze: it depends on the PSI band, and we decide two hours before class

Haze is the one that confuses people most, because a lesson is not automatically off when the PSI crosses 100. What changes is intensity.

• PSI 0 to 100: normal lessons.

• PSI 101 to 200: outdoor lessons continue at reduced intensity with more rest; indoor backup where available.

• PSI 201 to 300: outdoor lessons suspended; indoor only, with low exertion and venue permission.

• PSI above 300: everything suspended.

About two hours before class we check NEA's 1-hour PM2.5 reading for that part of the island alongside the 24-hour PSI, then message the class WhatsApp group. If conditions worsen during the afternoon, you get a second message. Any haze-affected lesson, including one you choose to skip for a child with asthma or a heart or lung condition, becomes a makeup credit valid for 90 days.

The full breakdown, including indoor alternatives such as dry-land technique and video analysis, is on our haze policy page.

3. Scheduled closures: the ones you can plan around

Every public pool has a weekly maintenance day. In the west, Bukit Batok Swimming Complex and Senja-Cashew Swimming Complex both close all day on Wednesday. Online listings sometimes show an afternoon reopening or a Thursday closure; both are wrong.

Then there are the long ones. Toa Payoh Swimming Complex is closed for redevelopment until around 2030, and Kallang Basin Swimming Complex closed permanently in September 2025. Fewer pools means fuller lanes everywhere else, which is why weekend morning slots in the west fill months ahead.

A facility or water-quality closure, for example after a fouling incident or a filtration fault, works like a scheduled closure: the venue tells us, we tell you, and the lesson is rescheduled rather than lost.

How you will hear, and what to do if you are unsure

All cancellations come through the class WhatsApp group, with the next step stated in the same message so you are not left guessing. If you have not heard anything and the weather looks bad, the lesson is on until you are told otherwise. If you are unsure, reply in the group before you leave home.

Frequently asked questions

Does a thunderstorm cancellation use up my makeup lesson?

No. A pool closure on lightning is a school-side cancellation and is credited separately from your own makeup allowance.

Is my child's lesson cancelled when PSI is above 100?

Not automatically. Between PSI 101 and 200 lessons run at reduced intensity with extra rest. Outdoor lessons stop at 201 and everything stops above 300.

What if the storm clears halfway through the lesson slot?

The venue reopens the water about 30 minutes after the last thunder. If enough time remains, the coach runs a shortened lesson and the admin confirms in the group.

Alvin Ng is Head Coach at Swim Masters Singapore, which runs lessons at public pools and condominiums across western Singapore. Coaches are NROC-certified and MOE-registered.