If you've lived in Singapore for a while, you probably know the feeling.

You wake up, look out the window and notice that the skyline doesn't look quite right. The air seems a little smoky. The usual view across the buildings looks washed out. Maybe there's a faint smell in the air.

Then comes the inevitable question:

Is the haze back?

Haze is something Singapore has had to deal with for years, particularly during prolonged dry periods when smoke from regional fires is carried across the region.

But seeing a hazy sky doesn't necessarily tell you how bad the air actually is. That's where the PSI and PM2.5 readings come in.

So if you're wondering what the haze means, whether it's safe to go for your morning run, what mask you should wear, or what to do if you work outdoors, here's a straightforward guide.

Is there haze in Singapore right now?

The first thing to know is that how hazy it looks isn't always a good indication of the actual air quality.

Singapore's National Environment Agency (NEA) monitors air quality around the island and publishes both 1-hour PM2.5 readings and the 24-hour PSI.

These are the numbers worth checking before deciding whether to spend a lot of time outdoors.

The official 24-hour PSI categories are:

PSI	Air quality
0–50	Good
51–100	Moderate
101–200	Unhealthy
201–300	Very Unhealthy
Above 300	Hazardous

You can check the latest readings and forecast at the official Singapore haze portal.

The useful thing about checking the numbers is that you don't have to guess.

A grey-looking sky might simply be cloudy. Conversely, the air can contain elevated levels of fine particles even when the sky doesn't look particularly dramatic.

So what exactly is haze?

 

In simple terms, haze is what happens when tiny particles and pollutants build up in the air and reduce visibility.

Singapore's more serious haze episodes are usually linked to smoke from fires in the region, particularly in parts of Sumatra and Kalimantan.

When conditions are dry, fires can produce large amounts of smoke. If the winds are blowing in the right direction, that smoke can travel towards Singapore.

That's why haze can seem to arrive almost overnight.

One day you're looking across the island at a perfectly clear skyline. The next morning, everything looks slightly brown and smoky.

It isn't necessarily because something has suddenly happened in Singapore itself. Sometimes the source is hundreds of kilometres away.

PSI vs PM2.5: which one should you look at?

You'll often hear both terms whenever there's haze, and it's easy to wonder which number actually matters.

PSI gives you a broader picture of Singapore's air quality over a 24-hour period.

PM2.5 refers to extremely small particles measuring 2.5 micrometres or less in diameter.

For everyday decisions, both are useful—but in different ways.

If you're wondering "Should I go for a long run outside this morning?", looking at the latest PM2.5 reading is useful.

If you're wondering "What are conditions likely to be like today?", the 24-hour PSI and forecast give you a better picture.

The important thing is not to obsess over one number in isolation. Look at the latest readings and the official advice for the conditions you're dealing with.

Is haze bad for you?

It can be.

For many healthy people, short-term exposure to haze may cause fairly familiar annoyances: irritated eyes, a scratchy throat, coughing or general respiratory discomfort.

People with existing heart or lung conditions can be more sensitive to poor air quality. Children, older people and other vulnerable groups should also take extra care when the air becomes unhealthy.

And there's another factor that's easy to overlook:

How hard you're breathing matters.

Walking to the coffee shop for ten minutes isn't the same as spending two hours doing a hard outdoor workout.

The harder you exercise, the more air you breathe in.

That's why one of the simplest things you can do when haze gets bad is to cut back on prolonged or strenuous outdoor activity.

Should you still exercise outdoors?

If the air quality is good or moderate, there's generally no reason to panic about going outside.

But when the PSI moves into the Unhealthy range, it makes sense to rethink that long run or intense outdoor workout.

You could:

* Run indoors instead
* Shorten your workout
* Exercise less intensely
* Take more breaks
* Choose a time when air quality is better
* Check the latest PM2.5 reading before heading out

Nobody needs to be afraid of stepping outside every time the sky looks a little hazy.

The point is simply to avoid unnecessary exposure when conditions deteriorate.

What if you have to work outdoors?

This is where haze becomes a little more complicated.

Not everyone can simply decide to stay indoors.

Construction workers, delivery riders, landscapers, cleaners, traffic personnel, security officers and countless others still have to get on with their jobs when the air isn't great.

If you're one of them, it's worth paying attention to the official workplace guidance rather than simply looking at the sky and deciding that it "doesn't seem too bad."

When haze becomes more severe, employers may need to reduce prolonged or strenuous outdoor work, provide more opportunities for indoor rest and take other measures to reduce workers' exposure.

If outdoor work can't be avoided, appropriate respiratory protection may also be necessary depending on the conditions.

And don't forget your eyes.

After spending several hours outdoors, your eyes can feel dry, irritated and uncomfortable. A comfortable pair of sunglasses can make a surprisingly noticeable difference.

If you're going to be outside for work anyway, a pair of Sunday Shades can be a simple addition to your everyday outdoor gear.

They're lightweight, secure and designed to stay comfortable when you're moving around—which is exactly what you want when you're spending a long day outside.

Just to be clear: sunglasses don't filter PM2.5 and don't protect your lungs from haze. Think of them as protection and comfort for your eyes, while appropriate respiratory protection is what matters for airborne particles.

Should you wear an N95 mask?

This is probably one of the most common questions whenever haze returns.

The answer isn't simply "yes" or "no."

For a short trip outdoors during moderate conditions, an N95 isn't necessarily something everyone needs.

As haze becomes more severe, however, reducing exposure becomes increasingly important. If you're going to spend a prolonged period outdoors—particularly doing strenuous work—appropriate respiratory protection becomes much more relevant.

If you already have a heart or lung condition, or you're otherwise in a group that's more vulnerable to air pollution, follow the official health advice for your situation.

And remember that a mask and sunglasses do completely different jobs.

A mask can help reduce inhalation of fine particles when properly fitted.

Sunglasses can help make your eyes more comfortable outdoors.

You don't want to mistake one for the other. 😏

What can you do at home during haze?

If the PSI starts climbing, there are a few simple things you can do.

Keep an eye on the air quality

This is probably the most useful habit.

Don't rely solely on how the sky looks. Check the latest PM2.5 and PSI readings before planning a long period outdoors.

Reduce unnecessary outdoor time

If conditions are unhealthy, there's little benefit in spending hours outside simply because you normally would.

Move your workout indoors. Put off that unnecessary outdoor activity. Take breaks from being outside.

Stay hydrated

Singapore is hot enough without adding haze to the equation.

Drink plenty of water, particularly if you still need to spend time outside.

Pay attention to how you feel

If your eyes are burning, your throat feels irritated or you're coughing more than usual, that's a good reason to reduce your exposure.

And if you're experiencing significant or persistent symptoms, especially if you have an existing medical condition, seek medical advice.

Does rain get rid of haze?

Sometimes it helps.

Rain can wash particles out of the air and improve visibility. That's why Singaporeans often get a little excited when those dark clouds finally roll in during a haze episode.

But rain doesn't necessarily mean the haze problem is finished.

If fires continue burning elsewhere and winds change again, smoky conditions can return.

The same goes for wind. A change in wind direction can sometimes clear Singapore surprisingly quickly.

So rather than assuming "It rained, so the haze is over," check the latest readings.

Why does Singapore get haze?

The short answer is: fires + dry weather + wind.

During dry periods, vegetation and peatlands in the region become more susceptible to fires.

Those fires produce smoke.

If the prevailing winds carry that smoke towards Singapore, we get haze.

It's why Singapore's haze tends to be associated with particular periods of the year, although the exact timing and severity can vary.

And it's also why one year's haze season can be completely different from another.

Some years barely make headlines.

Other years, the haze becomes impossible to ignore.

How long does haze usually last?

There's no fixed answer.

It could improve within a day. It could hang around for several days. During a more serious regional episode, conditions can persist for longer.

It depends on what's happening with the fires, rainfall and wind patterns.

That's another reason why an old article saying "the haze will last three days" isn't particularly useful.

The situation can change quickly.

For the most accurate information, check the latest official forecast.

What should you do when haze returns?

You don't need to panic.

You don't need to spend the entire day staring at the PSI either.

Just make a few sensible adjustments.

Check the air quality.
Know what the current PM2.5 and PSI readings are before spending a long time outdoors.

Cut back on strenuous outdoor activity.
Especially when the air reaches unhealthy levels.

Protect yourself if you need to be outside.
Follow the official advice on respiratory protection when conditions warrant it.

Look after your eyes.
If you're spending hours outdoors, comfortable sunglasses can help with eye irritation and glare.

Stay hydrated.

And if you work outdoors, take the conditions seriously.
You may not be able to stay inside, but there are still ways to reduce your exposure.

For outdoor workers, a pair of Sunday Shades can be a useful part of your everyday kit—especially if you're already spending most of the day under the Singapore sun.

Just remember that sunglasses are for your eyes, not your lungs.

Where can you check Singapore's haze and PSI?

When you want to know whether Singapore is experiencing haze, go straight to the official sources rather than relying on an old social-media post.

The NEA and haze.gov.sg provide Singapore's latest air-quality readings, PSI, PM2.5 information, forecasts and health advisories.

You can also use Singapore's official environmental information services for updates.

And if you're an employer or outdoor worker, check the Ministry of Manpower's guidance on working safely during haze.

Haze in Singapore: the bottom line

Haze is frustrating, particularly when you live in a place where being outdoors is such a normal part of everyday life.

But you don't need to overreact every time the skyline looks a little cloudy.

The simplest approach is to check the numbers, pay attention to the forecast and adjust your activities when air quality deteriorates.

If you're healthy and conditions are moderate, you can generally go about your day.

If the air becomes unhealthy, reduce prolonged or strenuous outdoor activity.

And if you're one of the many people who have to work outside, take sensible precautions, use appropriate respiratory protection when necessary, stay hydrated and look after your eyes too.

Because the haze may be something we can't control.

How much exposure we choose to have is another matter.