Monday, October 19, 2026 · United States
Skin weather in San Francisco UV index & humidity today
What today’s weather in San Francisco does to your skin – based on current forecast data for UV, humidity and air quality.
Updated Oct 19, 2026, 1:10 AM local time
Today · Temperature11 to 16 °C
Low and high-
UV index
5.1
moderate
Peak UV index today: 5.1 – moderate.
From UV 3, the WHO recommends sun protection: sunscreen with SPF and shade around midday.
-
Humidity
48%indoors when heated
balanced
Outdoors 77% humidity – heat it to 21 °C and only around 48% is left indoors.
Balanced humidity – your usual routine works well.
-
Pollen
–
No pollen forecast is available for this region.
-
Air quality
34EAQI
fair
European Air Quality Index up to 34 – fair. Fine dust (PM2.5) averages 9.1 µg/m³.
Clean air – no extra cleansing needed.
Tomorrow
- 11 to 19 °C
- UV 3.1 · moderate
- 46% · balanced
- Air quality: fair
Skin climate in San Francisco through the year
When the air in San Francisco is driest and when the sun is strongest – based on climate data from recent years.
- Indoor air in San Francisco is driest in February: heated to 21 °C, humidity indoors drops to around 39%.
- From November to April, the average daily temperature stays below 15 °C – the time when heating is usually on.
- From March to September, the midday sun climbs higher than 45° – your shadow is then shorter than you are. According to the WHO shadow rule, UV is then usually high.
- July brings the most sunshine, with around 407 hours.
| Month | Sunshine | Midday sun | Humidity outdoors | Indoors when heated | Avg. high |
|---|---|---|---|---|---|
| Jan | 221 h | 31° | 77% | 40% | 15.3 °C |
| Feb | 233 h | 39° | 73% | 39% | 16.4 °C |
| Mar | 301 h | 49° | 72% | 40% | 16.7 °C |
| Apr | 345 h | 62° | 70% | 43% | 19 °C |
| May | 398 h | 71° | 68% | – | 21.2 °C |
| Jun | 400 h | 76° | 70% | – | 22.6 °C |
| Jul | 407 h | 74° | 74% | – | 23.3 °C |
| Aug | 384 h | 66° | 73% | – | 24.7 °C |
| Sep | 334 h | 54° | 73% | – | 24.9 °C |
| Oct | 294 h | 43° | 70% | – | 23 °C |
| Nov | 240 h | 33° | 75% | 45% | 18.1 °C |
| Dec | 197 h | 29° | 84% | 44% | 14.2 °C |
Indoors when heated = humidity when outdoor air is warmed to 21 °C (only months with a daily average below 15 °C). Midday sun = sun angle in mid-month.
Frequently asked questions
What is the UV index in San Francisco today?
Today (October 19) the UV index in San Francisco reaches up to 5.1 – moderate. From UV 3, the WHO recommends sun protection: sunscreen with SPF and shade around midday.
How dry is the air in San Francisco today?
Outdoors 77% humidity – heat it to 21 °C and only around 48% is left indoors. Balanced humidity – your usual routine works well.
When is the air driest in San Francisco?
Indoor air in San Francisco is driest in February: heated to 21 °C, humidity indoors drops to around 39%. From November to April, the average daily temperature stays below 15 °C – the time when heating is usually on.
When is UV strongest in San Francisco?
From March to September, the midday sun climbs higher than 45° – your shadow is then shorter than you are. According to the WHO shadow rule, UV is then usually high. July brings the most sunshine, with around 407 hours.
Your skin weather, every morning.
Lumée reads UV, humidity, pollen and air quality for your location and turns them into skincare that fits this exact day.
Skin weather nearby
All cities →Data: WDTEC GmbH’s own weather servers – temperature, UV index and humidity from weather models, air quality and pollen from the Copernicus Atmosphere Monitoring Service (CAMS). Ratings: UV per WHO, air quality per European Air Quality Index, pollen per NAB. Skincare tips are general recommendations and do not replace medical advice.