Sunscreen in Winter : Why It Matters

Sunscreen in Winter: Why It's Non-Negotiable in Quebec

In short: UVA rays, responsible for skin ageing, are present year-round, pass through clouds and glass, and are reflected by snow. A broad-spectrum SPF 30 minimum therefore applies every day, January included. After an aesthetic treatment, SPF 50 becomes necessary to avoid post-inflammatory hyperpigmentation.

Here's why, and how to do it properly.

Do I really need sunscreen in winter?

Yes. It's the question we get most often, and the confusion comes from a logical shortcut: we associate sun with heat, and a Montreal winter isn't hot.

But there are two distinct forms of radiation.

UVB causes sunburn. It varies strongly with season, time of day and latitude. It genuinely is weaker in January.

UVA makes up the bulk of ultraviolet radiation reaching the earth's surface. It penetrates deeper into the dermis, where it degrades collagen and elastin and drives melanin production. It's present year-round, sunrise to sunset, cloudy or clear.

Put simply: UVB burns, UVA ages. And UVA doesn't take the winter off.

Why Quebec winters are a special case

Three factors specific to our climate.

Snow reflects radiation. Fresh snow cover bounces a significant share of ultraviolet radiation back upward. You receive both direct and reflected exposure — under the chin, under the nose and around the eyes, areas normally spared and rarely protected.

Altitude amplifies it. If you ski, radiation intensity increases with elevation.

Glass doesn't block UVA. Your daily commute and the window beside your desk count toward cumulative exposure.

What does cumulative sun exposure actually cause?

Most of what we call "skin ageing" is in fact photoageing.

Fine lines, loss of firmness, uneven tone, brown spots, visible capillaries and rough texture largely stem from ultraviolet exposure accumulated over decades — not simply from the passage of time.

That's good news. Unlike age, exposure is modifiable.

Why is sunscreen critical after a treatment?

After microneedling, a peel, radiofrequency or laser, your skin is in active repair. Two consequences.

It's temporarily more vulnerable. The skin barrier is disrupted and photosensitivity is increased. Exposure that would be trivial otherwise no longer is.

The risk of post-inflammatory hyperpigmentation is real. When inflamed skin meets ultraviolet radiation, pigment cells can overreact and produce persistent brown pigmentation exactly where you were treated.

The outcome: a treatment meant to even your tone produces the opposite. This risk is higher in deeper phototypes, but it isn't exclusive to anyone.

That's why, after treatment, sun protection isn't recommended — it's required.

Which SPF should I choose?

SituationRecommended SPFNoteDaily use, indoor day30 broad spectrumOne careful morning application is enoughProlonged exposure, outdoors, skiing50 broad spectrumReapply every 2 hoursAfter an aesthetic treatment50 broad spectrumNon-negotiableMelasma or active pigmentation50 broad spectrum, tintedPigment also blocks visible light

"Broad spectrum" is mandatory. The SPF number only measures UVB protection. Without "broad spectrum" on the label, you know nothing about your UVA protection — which is to say, your protection against ageing.

Beyond 50, the gain becomes marginal.

Mineral or organic filters?

Mineral filters (zinc oxide, titanium dioxide) reflect and absorb radiation, work on application, and are generally well tolerated by sensitive, reactive or post-treatment skin.

Organic filters offer lighter, more invisible textures that are often more pleasant day to day.

The best sunscreen remains the one you actually apply every morning. A formula that's perfect on paper but unpleasant to wear protects nobody.

Tinted formulas have an added advantage: their pigments block part of the visible light spectrum, which is known to contribute to pigmentation — particularly relevant with melasma.

How much should I apply?

This is where nearly everyone falls short.

Sunscreen is lab-tested at 2 mg per square centimetre of skin. In practice, most people apply a third to a half of that. An under-applied SPF 50 does not deliver 50.

The benchmark for the face: roughly two finger-lengths of product — base to tip — for face and neck. That's more than you're probably using.

Don't skip the ears, eyelids, bridge of the nose, lips and back of the neck. Those are the areas everyone misses, and precisely where damage accumulates.

How often should I reapply?

With sustained exposure, sweating or swimming: every two hours.

For a day spent indoors, a careful morning application remains a solid base. Adjust to your actual life rather than a theoretical ideal — consistency beats intermittent perfection.

When do I resume sunscreen after a treatment?

It depends on the treatment.

After a non-ablative treatment with light recovery, sun protection usually resumes the next day, sometimes the same day.

After a treatment that leaves skin more sensitive or flaking, sun avoidance takes priority for the first few days, then protection resumes according to the instructions given in clinic.

These directions are part of your treatment plan. Follow the ones you received rather than a general rule found online.

What sunscreen doesn't do

It doesn't replace shade, covering clothing, sunglasses and a hat during prolonged exposure. It doesn't make intentional tanning safe. And it doesn't block 100% of radiation, whatever the number on the bottle.

It's a highly effective tool, not an absolute shield.

Frequently asked questions

Is the SPF in my foundation enough? Rarely. The amount of foundation applied is far below what's needed to reach the stated rating. Treat it as a bonus, not your primary protection.

Does sunscreen cause breakouts? Some occlusive formulas can contribute on acne-prone skin. Lightweight non-comedogenic textures and zinc oxide mineral filters are often better tolerated.

Do I need sunscreen on cloudy days? Yes. Clouds let a significant share of UVA through.

At what age should I start? Sun protection is relevant at every age. Ultraviolet damage accumulates from childhood onward.

Are sunscreens safe? Sunscreens sold in Canada are regulated by Health Canada. If you have concerns about a specific ingredient, mineral filters are an alternative.

The short version

• Broad spectrum, SPF 30 minimum, SPF 50 after treatment

• Every day, 12 months a year, cloudy days and winter included

• Roughly two finger-lengths for face and neck

• Don't skip ears, eyelids, lips and neck

• Reapply every two hours during sustained exposure

Personalized advice in Montreal

We advise on the formula suited to your skin type and treatment plan at your appointment, at 1 Place du Commerce, Suite 110, Nuns' Island (Verdun), Montreal.