The Artisun Sun Report: India's Skin Weather, July–September 2026
Artifacts by Artisun · Research · Issue 01, July to September 2026
UV, humidity and air quality across ten Indian cities through the monsoon, and how much sunscreen each kind of weather actually calls for.
The short answer
The monsoon does not switch the sun off, and this year it did not wash the air clean either. Across these ten cities humidity sits between 70 and 90 per cent, which lifts sunscreen off the skin as you sweat, while clear-sky UV stays high behind the cloud. In Delhi the rain failed to clear the air at all: July to September was its most polluted monsoon in seven years. Grey skies are the season's trap, not its reprieve.
cities sit at a humidity of 70 per cent or higher through the monsoon.
Delhi's July–September 2026 average AQI — its most polluted monsoon in seven years.
the amount of sunscreen people typically wear, compared with the dose it is tested at.
clear-sky midday UV stays high in most cities even under monsoon cloud.
The sun grid
Typical midday UV index by month for each city. The red columns are this quarter, the monsoon.
City by city, this quarter
What the weather did in each city from July to September, and how much to wear.
| City | Midday UV | Humidity | Air quality | Weather type | How much to wear |
|---|---|---|---|---|---|
| Delhi | High · 9–10 | 70–82% | Moderate · 105 | Humid monsoon | Origin, 2 pumps + reapply |
| Mumbai | High · 9–10 | 80–89% | Good–Moderate | Humid coast | Aura, 2–3 pearls |
| Bengaluru | Very high · 10–11 | 75–82% | Good–Moderate | Mild, humid | Either, full dose |
| Chennai | Very high · 11 | 75–85% | Good–Moderate | Hot, humid | Aura, 2–3 pearls |
| Kolkata | High · 9–10 | 83–89% | Moderate | Humid, heavy rain | Origin, 2 pumps + reapply |
| Hyderabad | Very high · 10 | 70–80% | Good–Moderate | Humid | Either, full dose |
| Ahmedabad | Very high · 9–10 | 75–82% | Moderate | Humid heat | Origin, 2 pumps |
| Jaipur | Very high · 10 | 65–79% | Moderate | Humid for the season | Origin, 2 pumps |
| Pune | High · 9–10 | 80–90% | Good–Moderate | Humid monsoon | Either, full dose |
| Shimla | Very high · 9–10 | 75–90% | Good | Wet, misty | Aura, 3 pearls |
Humidity: climatological monsoon norms (IMD station records, city climate tables). Air quality on the India AQI scale (101–200 is Moderate); Delhi’s 105 is the verified July–September 2026 average, other cities show the typical monsoon band. UV: typical midday clear-sky values, moderated day to day by cloud.
The dose gap
Every SPF and PA rating is measured at 2 mg of sunscreen per square centimetre of skin, roughly a quarter teaspoon for the face and neck. Studies of how people actually wear sunscreen keep finding far less, often around half. Protection drops faster than the amount does, so a thin layer of SPF 50 behaves more like a much lower number.
This is the part of the report that is not about the weather at all. It is about habit. The single biggest gain most people can make is not a higher SPF. It is wearing enough of the one they have, every day, monsoon included.
What to do with it
Humid coast
Mumbai, Chennai, Kolkata. Sweat thins the layer, so a lighter texture you will actually reapply beats a thick one. Aura, two to three pearls, again after a wet commute.
Humid inland
Pune, Hyderabad, Bengaluru. Grey mornings hide real UV. Wear a full dose daily; either formula works.
Monsoon north
Delhi, Jaipur, Ahmedabad. Humid for once, and this year not clean. Wear it indoors near windows too. Origin, two pumps.
Hill monsoon
Shimla. Cloud and mist with strong altitude UV. Do not let the cool air fool you. Aura, three pearls.
Questions people ask
Do I need sunscreen in the monsoon?
Yes. Clear-sky midday UV stays high through the monsoon, and UVA, the ageing and pigmenting part of the spectrum, passes through cloud and glass even on grey days.
Does rain or cloud block the sun?
Only partly. Cloud cuts some UVB, but UVA passes through much more easily, and bright overcast and wet surfaces can bounce UV back up at you.
Why won’t my sunscreen stay on in humid weather?
Sweat and moisture lift the film a sunscreen needs to work. A lighter texture and a top-up through the day hold up better than one thick morning layer.
Which sunscreen is best for humid weather?
An invisible gel such as Aura, or a light milk such as Origin, worn at a full dose and reapplied after heavy sweating.
Method and sources
Humidity figures are climatological monsoon norms from India Meteorological Department station records and city climate tables, checked city by city. Air quality is given on the India AQI scale; Delhi’s July–September 2026 average of 105, its most polluted monsoon in seven years, and its September average of 102, the lowest in five years, are from the Centre for Research on Energy and Clean Air’s analysis of official data and the Press Information Bureau, with other cities shown as typical monsoon bands. UV values are typical midday clear-sky figures by month from public UV climatology. The dose-gap section reviews published studies; Artisun did not run a study for this report.
- India Meteorological Department — city climate normals and UV
- Centre for Research on Energy and Clean Air; Press Information Bureau — Delhi monsoon 2026 AQI
- Central Pollution Control Board — National Air Quality Index
- Petersen & Wulf (2014); Young et al. (2018) — real-world sunscreen dose and UV protection
- World Health Organization — Global Solar UV Index
Cite this report
Artifacts by Artisun. This report is for general information and is not medical advice.