Are You Using Your SPF Correctly Even in Autumn and Winter?

Why mixing sunscreen with your skincare could reduce protection, when SPF still matters in the colder months, and how to use it correctly.

A recent conversation with a customer stopped me in my tracks.

She told me that she mixes her SPF with her other skincare products before applying everything together.

It raised an important question: if you mix sunscreen with your moisturiser, serum or facial oil, are you still getting the protection stated on the bottle?

And now that summer is behind us and we are moving into the cooler, darker days of autumn and winter, there is another question worth asking:

The answers are slightly more nuanced than you might think.

SPF stands for Sun Protection Factor. The SPF number primarily indicates protection against UVB radiation — the ultraviolet radiation most strongly associated with sunburn.

But UVB isn’t the whole story.

UVA radiation penetrates more deeply into the skin and contributes to photoageing and pigmentation as well as skin cancer risk.

That is why choosing a sunscreen simply because it says “SPF50” on the front isn’t enough. You should also check its UVA protection.

In the UK, NHS guidance recommends at least:

● SPF30

● at least 4-star UVA protection

The UVA symbol inside a circle is another recognised indication of UVA protection.

Broad-spectrum protection matters because we want protection from both UVA and UVB.

This is where our customer’s routine becomes important.

The safest advice is:

Layer, don’t mix.

A sunscreen is a carefully formulated product. Its UV filters, emulsifiers and other ingredients are designed and tested to create a sufficiently even protective film when applied at the appropriate amount.

If you squeeze sunscreen into your hand and mix it with facial oil, moisturiser, serum or another cosmetic product, you have effectively created a new, untested mixture.

You can also inadvertently dilute the amount of sunscreen you’re applying.

And if you’re no longer applying enough sunscreen, you shouldn’t assume that you’re receiving the SPF stated on the packaging.

This does not mean that moisturiser, serum or facial oil cannot be used alongside sunscreen.

Research involving moisturising creams and sunscreens found no significant reduction in sunscreen effectiveness when the products were applied separately in layers, shortly before or after one another.

That distinction is important.

Using skincare underneath your sunscreen: yes.

Mixing the products together before application: no.

So where should your facial oil fit?

This is particularly relevant to us at Shea.Delight because facial oils form part of our skincare range.

A simple morning routine could look like this:

1. Cleanse

Start with clean skin and use a cleanser appropriate for your skin type.

2. Treatment or serum

Apply any treatment product or serum you use.

3. Moisturiser and/or facial oil

If your routine includes a facial oil, use a small amount and allow the skincare underneath to settle.

You don’t necessarily need both an oil and a moisturiser. This will depend on your skin and the products you’re using.

4. Sunscreen

Apply sunscreen as a separate final skincare layer.

5. Make-up

Make-up can then follow.

The American Academy of Dermatology similarly recommends cleansing first, followed by treatments, moisturiser and/or sunscreen, and then make-up.

The important point is not to turn your sunscreen into a DIY formulation by mixing other products directly into it.

This is where we need some perspective.

UV radiation doesn’t disappear when summer ends.

Cloudy weather does not automatically mean there is no UV exposure, and UVA remains relevant outside the height of summer.

However, that doesn’t mean the risk is identical on a dark December morning in London and a sunny July afternoon.

The NHS provides a useful practical measure: the UV Index.

When the UV Index is 3 or above, the NHS recommends considering skin protection. In the UK, the strongest sun is generally between 11am and 3pm from March to October.

So rather than thinking:

“It’s winter, therefore I don’t need sunscreen.”

A better habit is:

“What is my UV exposure today, what am I doing, and does my skin have any particular reason to need additional protection?”

Someone spending most of a low-UV winter day indoors has a very different exposure from someone walking outdoors for several hours, skiing in reflected sunlight, travelling somewhere sunny or managing a photosensitive skin condition.

This deserves particular care because sunscreen advice is often presented as though every skin tone has exactly the same risk.

It doesn’t.

Higher levels of melanin provide some natural protection against UV radiation, and the British Association of Dermatologists notes that routine sun protection is rarely necessary in the UK for people with black or dark-brown skin solely to prevent sunburn and sun damage.

But there are important exceptions.

These include certain photosensitive conditions, vitiligo, lupus, increased skin-cancer risk and — importantly for skincare — pigmentation concerns such as melasma.

So darker skin does not mean that sun protection is irrelevant.

It means the advice should be individualised rather than fear-based.

Hyperpigmentation and melasma change the conversation

If you’re trying to manage melasma or troublesome hyperpigmentation, photoprotection becomes particularly important.

The British Association of Dermatologists recommends broad-spectrum SPF30 or higher with high UVA protection for melasma.

And there is another interesting part of the science.

Visible light matters too.

Visible light can contribute to pigmentation, particularly in darker skin tones.

This is why dermatologists sometimes recommend tinted sunscreens containing iron oxides for people with melasma or persistent pigmentation.

In a randomised controlled trial involving people with melasma, sunscreen providing protection against both UV and visible light produced greater improvement in melasma measurements than UV-only sunscreen when both groups were also receiving hydroquinone treatment.

More recent research continues to support the usefulness of iron-oxide-containing formulations for visible-light-induced pigmentation.

So for someone managing melasma, choosing the right sunscreen may matter as much as simply choosing the highest SPF number.

This is another area where many of us unintentionally reduce our protection.

The SPF on the bottle is based on sunscreen testing under controlled conditions. Applying too little means you will not obtain the labelled protection.

The NHS recommends approximately 6–8 teaspoons to cover an adult body.

For the face, the American Academy of Dermatology advises approximately one teaspoon to cover the face, described as roughly the amount along the length of the index and middle fingers.

Don’t forget commonly missed areas such as:

● ears

● neck

● hairline

● around the eyes

● backs of the hands

Research using UV photography has also found that people tend to miss areas of their face when applying SPF moisturisers, particularly around the eyelids.

This advice needs context too.

If you are outdoors and exposed to sunlight, dermatology guidance recommends reapplication approximately every two hours.

Reapply sooner after:

● swimming

● heavy sweating

● towel drying

● rubbing the product from the skin.

If you are spending most of a winter day indoors and away from meaningful sunlight exposure, that is obviously different from spending six hours outdoors.

Follow the instructions for your particular sunscreen and consider your actual exposure.

What about SPF in foundation and moisturiser?

An SPF moisturiser can provide sun protection if it is broad-spectrum, SPF30 or above and you apply enough of it.

The practical problem is application.

In a study involving 84 participants, researchers found that people left significantly more of their facial area uncovered when applying an SPF30 moisturiser than when applying an SPF30 sunscreen.

So seeing “SPF30” printed on a moisturiser or foundation doesn’t automatically guarantee that you’re achieving SPF30 protection in everyday use.

Five SPF mistakes worth avoiding

1. Mixing sunscreen with facial oil or moisturiser

Apply your skincare and sunscreen as separate layers.

2. Applying too little

A thin smear is unlikely to deliver the protection stated on the bottle.

3. Thinking clouds mean no UV

UV radiation can still reach your skin on cloudy days.

4. Looking only at the SPF number

Check UVA protection too.

5. Assuming one morning application covers an entire day outdoors

Reapply when you are spending prolonged periods outside, particularly after swimming, sweating or rubbing the skin.

At Shea.Delight, we believe good skincare isn’t about using as many products as possible.

It’s about understanding what you’re applying, why you’re applying it and how the products work together.

Natural facial oils and botanical skincare can form part of a well-considered skincare routine. But they do not replace tested sunscreen.

And importantly, natural does not automatically mean sun-protective.

Plant oils should not be relied upon as substitutes for a properly formulated and tested sunscreen.

So if you enjoy using a facial oil or serum in the morning, you don’t have to give it up.

Simply remember:

Allow your skincare to settle, apply an appropriate amount of sunscreen as its own layer, and adjust your sun-protection habits according to your skin, your circumstances and your UV exposure.

And yes — sun protection can still matter in autumn and winter.

The temperature outside isn’t what determines UV exposure.

American Academy of Dermatology Association (2025) How to apply sunscreen. Available at: American Academy of Dermatology website (Accessed: 6 October 2026).

American Academy of Dermatology Association (2026) Should I apply my skin care products in a certain order? Available at: American Academy of Dermatology website (Accessed: 6 October 2026).

British Association of Dermatologists (2024) Melasma. London: British Association of Dermatologists.

Castanedo-Cazares, J.P., Hernandez-Blanco, D., Carlos-Ortega, B., Fuentes-Ahumada, C. and Torres-Álvarez, B. (2014) ‘Near-visible light and UV photoprotection in the treatment of melasma: a double-blind randomized trial’, Photodermatology, Photoimmunology & Photomedicine, 30(1), pp. 35–42. doi:10.1111/phpp.12086.

de Gálvez, M.V., Aguilera, J., Leal, M., Sánchez-Roldán, C. and Herrera-Ceballos, E. (2022) ‘Sunscreens effectiveness are not altered by concomitant use of moisturizing creams: An ultraviolet reflectance photography study’, Photodermatology, Photoimmunology & Photomedicine, 38(3), pp. 250–258. doi:10.1111/phpp.12745.

Hayes, S., Mahon, C., Hayes, J. and Allen, M. (2019) ‘Application of SPF moisturisers is inferior to sunscreens in coverage of facial and eyelid regions’, PLOS ONE, 14(4), e0212548. doi:10.1371/journal.pone.0212548.

NHS (2026) Sunscreen and sun safety. Available at: NHS website (Accessed: 6 October 2026).