Sun, haze and pigmentation:
what changes by season in Singapore

Is there a high-UV season in Singapore?

No. Singapore sits roughly one degree north of the equator, and the National Environment Agency notes that it is common for the UV index to reach Very High and Extreme levels in the four hours between 11am and 3pm on a day with little cloud cover, with values close to zero at night. The agency adds that index values are higher in months with less cloud and when the sun is directly over the equator, so the year has brighter and greyer stretches rather than a summer and a winter.

Two things follow for skin. The hour matters more than the month: a clear midday carries the most ultraviolet, and a grey afternoon carries less but never none, because UVA passes through cloud and through window glass. The Northeast Monsoon, from December to early March, brings more rain and cloud, which lowers the index on wet days without switching it off. The sunscreen guide explains why daily use, rather than seasonal use, is the model for this latitude.

When is the haze season, and what does haze do to skin?

The Meteorological Service Singapore describes slight to moderate haze as common during the Southwest Monsoon, from June to September, and in light wind conditions during the inter-monsoon months of April, May, October and November, with severe episodes of transboundary smoke haze from time to time. Haze is fine particulate pollution, and a systematic review of the literature links long-term exposure to airborne particulate matter with pigment spots and wrinkles, through oxidative stress, inflammation and impaired barrier function.

The evidence is associative, and the same review places particulate matter alongside ultraviolet radiation as one of several environmental stressors that may act together. The practical reading is that haze is a second burden on skin already exposed to UV, not a substitute for it: sunscreen continues on hazy days, cleansing stays gentle rather than aggressive, and barrier care matters more rather than less. Antioxidant serums may be discussed, without any claim that they undo exposure.

“Everything I do in clinic works better on skin that is protected.”

Dr Sin YongOn sunscreen as the multiplier

How do melasma, PIH and sun spots behave through the year?

Each pigment type answers to a different driver, so the calendar affects each differently. Melasma is provoked by ultraviolet, by visible light and by heat, with hormones in the background, which is why it tends to deepen after a bright holiday, a hot outdoor week or time in a sauna, and why tinted sunscreen with iron oxides, hats and shade are discussed for it. It often improves with protection and topical therapy and tends to return when protection lapses; the melasma treatment page sets out the staged approach.

Post-inflammatory hyperpigmentation behaves differently. It is the mark inflammation leaves behind after acne, a bite, a rash or an over-aggressive treatment, and it darkens most when the skin is exposed while the mark is fresh. The weeks after a breakout, an injury or a laser are therefore the ones in which protection is least optional, whatever the month. Sun spots, or solar lentigines, reflect cumulative dose over years rather than last week's exposure; they appear on the cheeks, temples, forearms and backs of the hands, and new ones keep arriving while exposure continues. The pigmentation types page explains how the three are told apart on examination.

The table below sets out how each type responds and what changes in the plan. The common thread is that no pigment type has an off season in Singapore; what varies is how quickly a lapse in protection shows.

Do humidity and sweat undo sunscreen?

Partly, and that is where most protection in Singapore is lost. Sweat, humidity and towelling lift sunscreen off the skin, so a film applied at 8am has usually thinned by lunch. Reapplication after sweating, swimming or towelling, which in this climate describes most days, matters more than the choice of filter, and so does the amount: a quantity too small to feel like anything is too small to work. Water-resistant products hold up better to sweat but still come off with a towel.

Texture decides whether a sunscreen is worn at all. Chemical filters allow thin, invisible formulations that many people find easier in humidity; mineral filters, zinc oxide and titanium dioxide, suit many sensitive or reactive skins but can feel heavier and leave a cast. Tinted mineral products with iron oxides add visible-light filtering relevant to melasma, and the mineral sunscreen filters page sets out the detail. Whatever the filter, broad spectrum with a UVA rating, applied generously to the ears, hairline, neck and hands, is the specification, and a hat and shade cover what sunscreen misses.

When is laser timed around sun exposure and travel?

Laser is deferred over a recent tan, because tanned skin carries more melanin to compete for the energy, and that raises the risk of darkening afterwards in Asian skin. After any pigment treatment the skin is more vulnerable to ultraviolet, so the weeks following a session are planned to be indoor-leaning, with strict protection, no aggressive actives and no heat on the face. A beach holiday, an outdoor wedding or a trekking trip booked for the fortnight after a laser is a reason to move the laser, not the trip.

The type of pigment sets the pace. Sun spots on untanned skin are the most straightforward target for a pico laser, with protection afterwards to slow new ones; the pico laser page covers what it does and does not do. Melasma is approached conservatively, with photoprotection and topical therapy first and energy kept gentle or avoided while it is active, because heat can make it darker. Post-inflammatory marks are often left to fade under protection before any device is considered. Tell the clinic at the consultation about planned travel and outdoor commitments, because treatment is easier to time around exposure than to repair after it.

What should you do daily, and when should you see a doctor?

Daily, in every month: a broad-spectrum sunscreen with a UVA rating applied generously in the morning and reapplied after sweating or towelling; a hat and shade between 11am and 3pm when outdoors; sunscreen indoors beside bright windows and in the car; gentle cleansing on hazy days rather than scrubbing; and, if melasma is a concern, a tinted product with iron oxides and a wide berth around saunas and hot yoga. None of this clears pigment already deposited; it stops new pigment forming and protects treated skin.

The risks worth knowing are darkening after treatment, which is the commonest problem in Singapore skin and is prevented by timing and protection rather than by product choice, and reactions to specific sunscreen filters, which are a reason to change filter rather than abandon protection. See a doctor if a patch is changing in size, shape or colour, is raised, bleeds or looks unlike the others, because sun-damaged skin can hide more than pigment; if brown patches keep returning despite protection; or if darkening appears after a treatment. Contact the clinic on +65 8023 7170 during clinic hours.

What determines the fee for treating sun-related pigmentation?

Sunscreen is an over-the-counter purchase, and no brand is recommended here. Cost arises in treating what exposure has already done, and Singapore's rules prevent clinics from advertising prices, so no figures are given. The fee follows the plan: the area treated, what the assessment finds the pigment to be, whether one approach or a staged combination is used, and how it is sequenced around your calendar. Fees are written and itemised after consultation, and the how fees are quoted page explains what a written quote contains.