Do You Need Sunscreen in the Winter? When It Matters
Do you need sunscreen in the winter? Yes from UV index 3, on snow (it reflects over 80% of UV), at altitude and on long drives. At UV 0-2, minimal protection.
Short answer: yes, you need sunscreen in the winter in specific situations. Wear broad-spectrum SPF 30 whenever the UV index reaches 3, on fresh snow (which reflects over 80% of UV), at altitude, and on long drives, where car side windows let through about 29% of UVA. For a short errand at UV index 0-2, minimal protection is enough.
Winter changes the mix of ultraviolet light more than it removes it. Sunburn-causing UVB falls sharply; skin-aging UVA falls much less, passes through clouds and window glass, and bounces off snow. Below: what changes by season, what the EPA and WHO actually say about a UV index of 2, how clouds, snow and car windows change your dose, and a decision table you can use each morning.
Do you need sunscreen in the winter?
You need it on exposed skin whenever you will be outside at a UV index of 3 or higher, and in four winter situations where the index undersells your dose: snow, altitude, long drives and long hours beside a sunny window. On a gray 20-minute walk at UV index 1, the burn risk is low.
The American Academy of Dermatology (AAD) puts the year-round case plainly: “The sun emits harmful UV rays year-round” (AAD Sunscreen FAQs, last updated February 11, 2025). Most people do not act on it. In a February 2024 AAD survey, only 13% of Americans planned to use sun protection on cold-weather walks or hikes, 6% during outdoor winter sports or exercise and 4% while shoveling snow, and nearly 1 in 5 adults did not know you can get sunburned in winter. Dawn Davis, a board-certified dermatologist at Mayo Clinic quoted in that release, said: “Sun protection is vitally important because ultraviolet (UV) rays are always present, regardless of the season or time of day.”
There is also a long-term reason to keep a daily face habit. In a randomized trial of 903 adults in Nambour, Australia (latitude 26° S), people assigned to daily broad-spectrum sunscreen showed no detectable increase in skin aging after 4.5 years, and their skin aged 24% less than in the group using sunscreen at their own discretion (Hughes et al., Annals of Internal Medicine, 2013). That trial ran in a subtropical town with high UV all year, so it supports the daily habit rather than measuring winter UV specifically.
Is UV weaker in winter, and does UVA drop as much as UVB?
UV is weaker in winter, but UVB drops far more than UVA. When the sun sits low, its rays take a longer slanted path through the atmosphere, which filters the shorter UVB wavelengths more than UVA. A 2021 study in Photochemistry and Photobiology states that “the UVA/UVB ratio of sunlight is high in winter and low in summer in the Northern Hemisphere”; exposing DNA samples to natural sunlight for 8 hours in late summer and in winter, the authors found winter sunlight converted more of one DNA lesion type into another than late-summer sunlight at similar UV doses, an effect they attributed to the higher UVA share.
Two definitions make the rest of this guide easier:
- UVB is the shorter-wave ultraviolet that causes most sunburn. The AAD notes that window glass blocks it.
- UVA is the longer-wave ultraviolet linked to tanning, skin aging and dark spots. The AAD notes it “can pass through window glass.”
The UV index is a forecast of sunburn-weighted UV, so it mostly tracks UVB. A winter index of 1 or 2 tells you burning risk is low; it does not tell you UVA is negligible. Altitude adds to both. Austria’s UVA monitoring network, reported in 2019 after up to 5 years of measurements, found UVA rises 8% to 9% per 1,000 m of altitude, and in winter the daily UVA dose at Mt. Gerlitzen (1,540 m) was double that in Vienna (153 m).
Do you need sunscreen if the UV index is 2?
Usually not for a short time outside. The EPA’s UV Index scale says that at 1-2 (low) “you can safely stay outside using minimal sun protection,” and the WHO sets the threshold at 3: “At these levels there is an increased risk of skin damage, and protective measures are recommended” (WHO UV index Q&A, June 20, 2022).
UV index 2 is not “zero,” though. Three winter exceptions turn a 2 into a reason to apply:
- Fresh snow. Environment and Climate Change Canada says low UV “poses minimal risk, except when it’s bright and there is snow on the ground,” and that in winter snow can reflect UV “to almost double the index value.” A 2 on snow behaves closer to a 4.
- Long exposure. Minimal risk per minute still adds up over a full day outside, such as a hike, a ski day or outdoor work.
- Pigment-prone skin. If you are managing melasma or dark marks, the UVA that a low index barely registers still matters, so a daily broad-spectrum face sunscreen is the simple default.
For everyone else, a UV index of 2 with no snow and a short walk does not require sunscreen on exposed skin, though a daily face habit costs little.
Do you need sunscreen when it’s cloudy?
Yes, if the UV index is 3 or more. The AAD states that “even on cloudy days, up to 80% of the sun’s harmful UV rays can penetrate the clouds,” and the WHO notes UV “can be high even with cloud cover.” Environment and Climate Change Canada adds that “in cool or slightly cloudy weather, you still need to protect yourself.”
Cloud is not a reliable shield because cloud type matters more than how gray the sky looks: thin or broken cloud lets most UV through, while thick rain cloud blocks more, which is why the AAD figure says “up to.” Cold air does not filter UV either. The practical rule is to check the forecast UV index rather than the sky. If it reads 3 or above, apply as you would on a sunny day.
How much does snow increase UV exposure?
Fresh white snow can reflect over 80% of the sun’s UV, according to Environment and Climate Change Canada (page last modified April 20, 2026). On snow you receive UV from above and from below.
Reflected UV reaches areas that usually stay shaded: under the chin, the underside of the nose, the ears and under the eyes. Add altitude (UVA up 8% to 9% per 1,000 m in the Austrian data) and a ski day can deliver a summer-like dose to skin that has not seen sun in months. Spring skiing is the peak case: the sun is higher and the snow is still fresh. The AAD’s 2024 survey found 1 in 7 Americans did not know UV reflects off snow, water and sand.
On snow, use a broad-spectrum SPF 30 or higher (SPF 50 is reasonable for a full ski day or fair skin; see SPF 30 vs 50 for face), apply it under the chin and nose, add an SPF lip balm and wear UV-blocking goggles or sunglasses.
Do you need sunscreen in the car?
On longer drives, yes, on the side of your face and arm next to the window. The front windshield blocks almost all UVA; the side windows often do not.
In a 2016 cross-sectional study in JAMA Ophthalmology, ophthalmologist Brian Boxer Wachler measured outside UVA and UVA behind the windshield and driver’s side window of 29 cars from 15 manufacturers (model years 1990 to 2014, average 2010) in Los Angeles. Average UVA blockage was 96% for windshields (range 95% to 98%) and 71% for side windows (range 44% to 96%). Only 4 of the 29 cars (13.8%) blocked more than 90% of UVA at the side window. The study concluded: “The level of side-window UV-A protection was lower and highly variable.”
Turned into what gets through:
| Glass | Average UVA blocked | UVA reaching skin | Compared with windshield |
|---|---|---|---|
| Front windshield | 96% | about 4% | baseline |
| Side window, average car | 71% | about 29% | about 7 times as much |
| Side window, worst car tested | 44% | about 56% | about 14 times as much |
| Side window, best car tested | 96% | about 4% | similar |
Calculated as 100% minus blockage, from Boxer Wachler, JAMA Ophthalmology 2016. Calculations by Korea Glow Report, checked October 7, 2026.
Windshields are laminated, with a plastic layer between two panes, and the 2006 glass review cited below lists that interlayer among the factors that raise UV protection; side windows are usually a single pane that may or may not include a UVA filter. That fits an older pattern: a 2010 review of skin cancers at a US Mohs surgery unit found 31 of 42 melanoma in situ cases (74%) on the left side of the body, the driver’s window side in the US (Butler and Fosko, Journal of the American Academy of Dermatology). The abstract does not report driving habits, so it shows an association, not proof that car windows caused those cancers.
For a 10-minute errand, skip it. For a commute of an hour or more, a road trip, or a job that keeps you driving, apply broad-spectrum sunscreen to your face, neck and window-side arm, or ask a reputable installer about clear UV-blocking window film that complies with your state’s tint laws.
Do you need sunscreen indoors?
Not if you stay away from windows: walls and roofs block UV. Near a sunny window it depends on time and skin. A 2006 review of photoprotection by glass in the Journal of the American Academy of Dermatology (Tuchinda, Srivannaboon and Lim) states that window glass “filters out UVB and transmits UVA and visible light,” and that glass type, color, interlayer and coating change how much UVA gets through. Some newer glass blocks most UV, but you rarely know what your office or home windows are.
So: a room with curtains drawn or no windows needs no sunscreen. A desk beside a bright window for most of the day is a reasonable place for broad-spectrum face sunscreen, particularly for melasma or dark spots. If dark patches keep spreading despite daily protection, see a board-certified dermatologist.
When should you wear sunscreen in winter? A decision table
Use the forecast UV index and where you will be, not the temperature.
| Situation | What changes | Sunscreen needed? | What to use |
|---|---|---|---|
| City errand, UV index 0-2, no snow, under 30 minutes | Low UVB; UVA still present | Optional | Daily face SPF if you prefer the habit; minimal protection is enough per EPA |
| Any outdoor time at UV index 3 or above | WHO and EPA protection threshold | Yes | Broad-spectrum SPF 30 or higher on exposed skin |
| Overcast day, UV index 3 or above | Up to 80% of UV passes through clouds | Yes | Same as a sunny day |
| Fresh snow on the ground | Over 80% reflected; index nearly doubles | Yes, even at UV 1-2 when bright | SPF 30 or higher, under chin and nose, SPF lip balm |
| Skiing or mountains | Snow plus altitude; UVA up 8-9% per 1,000 m | Yes | SPF 50, reapply about every 2 hours, goggles |
| Drive of an hour or more | Side windows pass about 29% of UVA on average | Yes, window side | Face, neck and window-side arm, or UV film |
| Desk beside a sunny window most of the day | Glass passes UVA, blocks UVB | Recommended for pigment-prone skin | Broad-spectrum face sunscreen |
| Indoors away from windows | No meaningful UV | No | Nothing |
Compiled from EPA, WHO, AAD and Environment and Climate Change Canada guidance and the studies cited above, checked October 7, 2026.
What is the evidence behind these claims?
| Claim | Best evidence | Study type, size, duration | Strength |
|---|---|---|---|
| Daily sunscreen use slows visible skin aging | Hughes et al., 2013 | Randomized trial, 903 adults, 4.5 years | Moderate |
| Car side windows block less UVA than windshields | Boxer Wachler, 2016 | Measurement of 29 cars | Limited |
| Skin cancers in the US are more common on the left (driver) side | Butler and Fosko, 2010 | Retrospective case review | Limited |
| UVA rises with altitude and stays high in mountain winters | Schmalwieser et al., 2019 | Multi-year measurements at 3 stations | Limited |
| Protection is advised from UV index 3, or on snow at lower index | WHO, EPA, Environment Canada, AAD | Regulator and professional guidance | Guidance |
Do you need to reapply sunscreen in the winter?
Only when you are outside for long stretches. The usual rule of reapplying about every two hours outdoors applies on ski slopes and winter hikes, and sooner after sweating, wiping your nose or toweling off. Cold, wind and scarves rub sunscreen off faster than people expect.
The first application matters more. The SPF on the label assumes 2 mg of product per square centimeter of skin, and most people apply far less. Our guide to how much sunscreen to put on your face turns that into grams and teaspoons.
Does winter skincare change how sunscreen works?
It can change how well it stays on. Thicker winter creams and balms under sunscreen raise the odds of the sunscreen rolling into flakes, so give the moisturizer a few minutes to set and use less of it. Our guide to why sunscreen pills has a cause-to-fix table.
Dry indoor heat is the other winter variable. If your skin feels tighter after a humectant serum, the issue is usually low air humidity without a sealing cream on top; our guide to whether hyaluronic acid can dry out skin explains the layering. A well-sealed moisturizer followed by sunscreen covers both the dryness and the UV.
Sources and research notes
AAD sunscreen FAQs and its 2024 winter sun-protection survey release, the EPA UV Index scale, the WHO UV index Q&A and UV fact sheet, Environment and Climate Change Canada UV index guidance on snow and clouds, and peer-reviewed studies on car window UVA transmission, left-sided skin cancer, glass photoprotection, seasonal UVA/UVB ratio, altitude and winter UVA, and daily sunscreen and skin aging, checked on the date shown.
Source record date: 2026-10-07. Prices and availability are as of that date.
- American Academy of Dermatology: Sunscreen FAQs (last updated 2025-02-11)
- American Academy of Dermatology: Survey shows sun protection lacking in winter (news release, 2024-02-06)
- US EPA: UV Index Scale (protection advice by UV index)
- WHO: Radiation: The ultraviolet (UV) index, questions and answers (2022-06-20)
- WHO: Ultraviolet radiation fact sheet (2022-06-21)
- Environment and Climate Change Canada: How to use the UV index (snow reflection, winter; modified 2026-04-20)
- Boxer Wachler. Assessment of levels of UV-A light protection in automobile windshields and side windows. JAMA Ophthalmol 2016 (29 cars, 15 manufacturers)
- Butler and Fosko. Increased prevalence of left-sided skin cancers. J Am Acad Dermatol 2010 (Mohs unit, patients referred in 2004)
- Tuchinda, Srivannaboon and Lim. Photoprotection by window glass, automobile glass, and sunglasses. J Am Acad Dermatol 2006 (review)
- Nishimura et al. Seasonal differences in the UVA/UVB ratio of natural sunlight. Photochem Photobiol 2021 (DNA exposed to sunlight 8 h, late summer vs winter)
- Schmalwieser et al. The Austrian UVA-Network. Photochem Photobiol 2019 (3 stations, up to 5 years; UVA +8-9% per 1000 m)
- Hughes et al. Sunscreen and prevention of skin aging: a randomized trial. Ann Intern Med 2013 (n=903, 4.5 years)
Frequently asked questions
Can you get sunburned in the winter?
Yes. Snow can reflect over 80% of the sun's UV and nearly double the UV index, and UV rises with altitude, so ski days and bright snowy afternoons can burn. In a 2024 American Academy of Dermatology survey, nearly 1 in 5 adults did not know winter sunburn was possible.
Do you need sunscreen indoors if you stay inside all day?
Away from windows, no: UV does not pass through walls and roofs. Ordinary window glass blocks UVB but lets UVA through, so if you sit beside a sunny window for hours, broad-spectrum sunscreen on your face makes sense, especially if you get dark spots or melasma.
Do you need sunscreen in the car in winter?
On longer drives, yes for the side facing the window. In a 2016 study of 29 cars, windshields blocked 96% of UVA on average but side windows only 71%, with a range of 44% to 96%, and UVA is not seasonal in the way UVB is.
Do you need to reapply sunscreen in the winter?
When you are outdoors for long stretches, yes: reapply about every two hours, and sooner if you sweat or wipe your face, as on a ski day. For a desk day indoors, one morning application is usually enough.
Is SPF in my moisturizer or foundation enough in winter?
For a short commute at a low UV index, it can be. The SPF on the label assumes 2 mg of product per square centimeter, about a quarter teaspoon for the face, and few people use that much foundation, so for snow, altitude or long drives use a dedicated broad-spectrum SPF 30 or higher.