Skincare journal
Summer Skincare and SPF: The Step Most People Still Skip
Why UVA matters more than the number on the bottle, how much you actually need to apply, and why this holds in Dorset as much as anywhere hotter.
Sunscreen is the single most effective thing you can do for how your skin looks in twenty years, and it is still the step most people leave out. Not through laziness particularly, but because the advice has always been vague and slightly patronising. So here is the version that actually explains why.
Two types of ultraviolet, and only one of them burns you
UVB is the shorter wavelength. It burns. It is strongest in the middle of the day, in summer, and it is largely blocked by glass and by heavy cloud. The SPF number on a bottle mainly describes protection against UVB.
UVA is the longer wavelength. It does not burn, so there is no immediate feedback telling you it is happening. It penetrates deeper, breaks down collagen and elastin, and drives pigmentation. It passes through cloud and through window glass, and its levels stay far more constant across the day and across the seasons than UVB.
UVB is why you go red on a beach in August. UVA is why the skin on your face looks older than the skin on your inner arm. Most visible skin ageing is UVA, accumulated slowly, on days nobody thought counted.
This is why the UVA rating matters as much as the SPF number. In the UK, look for the UVA logo in a circle or a four or five star rating alongside the SPF. An SPF 50 with poor UVA protection is worse for ageing than an SPF 30 with excellent UVA protection.
Why Dorset counts
The assumption that sunscreen is for holidays is where the damage happens, because the ordinary days add up to far more exposure than the fortnight abroad.
Walking at Moors Valley, standing on the touchline, gardening on an overcast afternoon, driving with the sun through the side window. None of it feels like sun exposure. All of it is UVA. Add up a couple of hours a day for thirty years and the total dwarfs the two weeks a year anyone actually applies sunscreen for.
The coast makes it worse, because water and light sand reflect ultraviolet upwards. A day on the beach at Bournemouth or Studland delivers more than the same day inland.
How much to use
This is where most sunscreen fails, and it has nothing to do with the product.
SPF ratings are tested at two milligrams per square centimetre of skin. In practice, most people apply somewhere between a quarter and a half of that. Protection does not scale in a straight line, so applying half the amount of an SPF 30 leaves you with considerably less than SPF 15.
The practical measure is two finger lengths. Squeeze a line of sunscreen along the length of your index finger and your middle finger, and that is one application for the face and neck. It will look like far too much. It is the correct amount.
Reapply every two hours if you are outdoors, and after swimming or heavy sweating. On a normal indoor day, once in the morning is a reasonable compromise.
The rest of a summer routine
Summer skin usually needs less rather than more.
- Lighter moisturiser. Humidity is higher and skin loses less water, so what felt right in February often feels heavy in July
- Keep the hydrating serum. Air conditioning and long days outside are both dehydrating, so this stays useful
- Careful with actives. Retinol and strong acids make skin more sun sensitive. Keep them to the evening, and cut back if you are outside a lot
- Cleanse properly at night. A day of sunscreen and sweat needs a double cleanse. This is the main reason people break out in summer, and it is not the sunscreen’s fault
Facials and sun exposure
Two things worth knowing about the timing.
Do not book a facial immediately after significant sun exposure. Skin that has caught the sun is already inflamed, and exfoliating it is a bad idea even if it is not visibly burnt.
And do not go straight into strong sun after a facial. Exfoliated skin is more vulnerable, which is why every treatment finishes with SPF applied properly rather than as an afterthought. The walk through of an appointment covers the finishing steps.
Summer is also the season when pigmentation becomes obvious, and pigmentation is the concern where sunscreen does the most work. Any treatment aimed at evening out skin tone is largely wasted without daily SPF, because you would be lifting pigment while continuing to trigger it.
If you take one thing from this
Find a sunscreen you genuinely do not mind wearing, keep it next to your moisturiser, use two finger lengths, and put it on every morning regardless of the weather. That single habit outperforms every serum on the market.
Want help picking one that suits your skin? It comes up in nearly every appointment. Ask about a treatment and bring the question with you.
Common questions
Around two finger lengths, squeezed along the index and middle finger, which works out at roughly a third of a teaspoon for the face and neck. Most people apply less than half of that, which drops the real protection well below the number on the bottle.
If you sit near a window, yes. UVA passes through glass and it is the wavelength most responsible for visible ageing and pigmentation. UVB, which causes burning, largely does not.
Rarely, because you would need to apply far more moisturiser than most people do to reach the stated protection. A separate sunscreen applied as the last step of your morning routine is more reliable.
