Heat, haze and dengue in Singapore

Singapore is one degree north of the equator, so there's no winter, no fall and no break. Add haze from regional fires in some years and a mosquito that spreads dengue, and you've got three health basics every newcomer should learn in the first month.

The short version

It's hot all year. Singapore's 2025 mean temperature was 28.1°C (82.6°F), and the island set a record high of 36.0°C (96.8°F) on November 1, 2025 [1].
Check the heat stress advisory on the myENV app or weather.gov.sg. It rates heat stress as low, moderate or high, using a measure that combines temperature, humidity, sun and wind [2][3].
Haze comes and goes. On September 4, 2026, the 24-hour PSI hit the Unhealthy range (101 and up) for the first time since October 2023, and NEA started daily haze advisories [4].
Dengue is year-round. NEA logged 2,832 cases in the first 43 weeks of 2026 [5]. The Aedes mosquito bites by day and breeds in clean standing water, often in homes.
Your insurance matters if you end up in the hospital with dengue or heat illness. See our healthcare guide.

Heat and humidity: the real adjustment

Phoenix in July is hot. Houston in August is sticky. Singapore is both, every month, and it never cools down much at night. The temperature is only part of it: humidity is high, so sweat doesn't evaporate well and your body has a harder time shedding heat.

The numbers keep creeping up. The Meteorological Service Singapore's 2025 climate report, released March 23, 2026, put the annual mean at 28.1°C (82.6°F), joint eighth warmest on record, with warming of about 0.24°C (0.43°F) per decade since 1984 [1]. June and November 2025 were each the warmest since records began in 1929, and Singapore had 29 high heat stress days in 2025 [1].

It's also wet. 2025 brought 2,984.9 mm (about 117.5 inches) of rain, and March was the wettest on record [1]. Expect sudden, heavy afternoon thunderstorms that clear in an hour, and carry an umbrella for both sun and rain. Singaporeans do.

The heat stress advisory

Since 2023, the government has published a Heat Stress Advisory on the myENV app and weather.gov.sg [2]. It's based on the Wet Bulb Globe Temperature (WBGT), which factors in humidity, sunlight and wind rather than air temperature alone.

Heat stress level	WBGT	What to do [3]
Low	Below 31°C (87.8°F)	Normal activities; drink as usual
Moderate	31°C to under 33°C (87.8°F to 91.4°F)	Cut back outdoor activity, take shade breaks, drink extra fluids, use a hat or umbrella
High	33°C (91.4°F) and up	Limit outdoor activity, take longer breaks, cool down actively, wear light, pale clothing

Singapore's highest heat stress reading on record, a WBGT of 35.0°C (95.0°F), came at Palawan Green on Sentosa on October 31, 2025 [1].

Habits that work

Run, cycle or play tennis early. Before about 8 a.m. or after sunset is the sweet spot. Midday is for the air-conditioned gym or the mall.
Drink before you're thirsty. Carry a refillable bottle; tap water in Singapore is safe to drink.
Dress for it. Light, loose, pale clothes. Office dress codes are often relaxed for this reason, but buildings are cold, so keep a light layer at your desk.
Use the covered walkways. The city is laced with sheltered paths linking MRT stations, malls and HDB blocks. Plan walks along them.
Know the warning signs of heat exhaustion: dizziness, headache, nausea, heavy sweating, cramps. Confusion or a stop in sweating is an emergency; call 995.
Watch kids, older relatives and new arrivals. Visitors from a US winter take a week or two to adjust. Don't plan a long walking tour for your parents' first afternoon.

Haze: when the sky turns gray

Haze is smoke from land and forest fires in the region, mostly in Indonesia, drifting over on the wind. It isn't every year. Singapore went from October 2023 to September 2026 without a haze-related Unhealthy reading, and then on September 4, 2026, the 24-hour PSI in the central region reached 101 [4].

Reading the PSI

NEA reports the Pollutant Standards Index (PSI) and PM2.5 readings on haze.gov.sg, nea.gov.sg and the myENV app, and issues daily haze advisories with a 24-hour PSI forecast when haze sets in [4].

24-hour PSI	Band	What NEA and MOH advise [4]
100 and below	Good to moderate	Normal activities
101 to 200	Unhealthy	Everyone: reduce outdoor activity and exertion, drink plenty of water. Keep heart and lung medication handy
201 to 300	Very unhealthy	Vulnerable people (older adults, pregnant women, children, people with heart or lung conditions) avoid or minimize outdoor activity
Above 300	Hazardous	Healthy people who must be outdoors for several hours may wear an N95 mask

What actually happens on a haze day

The government's playbook kicks in quickly. In the September 2026 episode, MOE said every classroom in primary and secondary schools and junior colleges has air purifiers, preschools cut outdoor play when air quality is Unhealthy or worse, and MOM told employers to reduce prolonged or strenuous outdoor work [4].

On masks, the official advice is more relaxed than many Americans expect. MOH says you don't need an N95 for short exposure like a commute or for indoor settings. A healthy person who must be outside for several hours may wear one when the forecast is Hazardous; vulnerable people may wear one for several hours outdoors when it's Very Unhealthy, after checking with a doctor if they have severe heart or lung conditions [4].

What that means at home:

Keep a box of N95s and an air purifier sized for your bedroom. When haze hits, both sell out.
Close the windows and run the air conditioning on recirculate.
If you have asthma or COPD, refill your inhalers before the dry season and talk to your doctor about a plan.
Follow NEA's forecasts rather than the smell outside; the 24-hour PSI is what the advisories are based on [4].

Dengue: the mosquito you need to know

Dengue is a viral illness spread by the Aedes mosquito, which NEA describes as easy to spot by the black and white stripes on its body [6]. Unlike the dusk-biting mosquitoes at a lake cabin back home, Aedes bites during the day. And it prefers clean, stagnant water in and around homes: flowerpot saucers, vases, roof gutters, a bucket on the balcony [6].

How big a risk?

It varies a lot by year and neighborhood. In the week ending October 31, 2026, NEA reported 68 cases, bringing the 2026 total to 2,832 after 43 weeks [5]. As of November 2, there were 11 active dengue clusters, three of them red alerts with 10 or more cases [5]. NEA's dengue page maps clusters by street, so check it when you're choosing where to rent. NEA has said transmission is usually higher in the warmer months from June to October [7].

Dengue usually starts with a sudden high fever, severe headache, pain behind the eyes, and muscle and joint aches. Most people recover, but some develop severe dengue, which needs hospital care. If you have a fever in Singapore, see a doctor rather than waiting it out, and skip ibuprofen and aspirin until dengue is ruled out, since they can raise bleeding risk.

Keeping mosquitoes out of your home

NEA's B-L-O-C-K steps are the local version of "check your yard after it rains" [7]:

Break up hardened soil in plant pots.
Lift and empty flowerpot plates.
Overturn pails and wipe their rims.
Change water in vases.
Keep roof gutters clear and place BTI insecticide in them.

NEA does check homes for breeding and can take enforcement action, so treat this as a weekly chore, not a suggestion. For personal protection, use repellent on exposed skin during the day, especially near parks and greenery, and screens or a fan at home. Under Project Wolbachia, NEA also releases male Aedes aegypti mosquitoes carrying Wolbachia bacteria in selected areas to suppress the population, and the releases target only that species [8]. NEA's page on the project notes that male mosquitoes don't bite.

Staying well: the American angle

Insurance. A few days in a hospital with dengue, or an ER visit for heat illness, is billed at unsubsidized rates if you're on a work pass. Check what your plan covers before you need it.
Alerts. Register with STEP so the US Embassy can send you health alerts, and turn on myENV notifications for haze and heat.
Ask around. For which neighborhoods are breezy, which condos spray, and which air purifiers held up last haze season, ask in our community group for Americans in Singapore.

Heat, haze and dengue in Singapore: staying well in the tropics