Worst air pollution Winchester, today and tomorrow
Today (16 July): Air quality in Winchester is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 2:00 PM (O3: 35.5/100).
Tomorrow (17 July 2026): Air quality in Winchester is medium. AQI improves to medium; O3 decreases to medium; all other pollutants stay as today. Pollution peaks around 4:00 PM (O3: 48.7/100). Airmine updates local air quality forecasts four times daily.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Air quality in Winchester is shaped by its location in Hampshire, where vehicle traffic and everyday urban activity dominate local sources. The area's changeable Atlantic weather help ventilate the town centre, keeping air quality at moderate levels typical for the region. The nearby A55 corridor contributes steady vehicle emissions that affect roadside readings.
Today - 16 July | Pollution peaks at 14:00
AQI:
Fair
35.5/100
PM2.5 (fine particles):
Good
7.9/100
PM10 (coarse particles):
Good
2.8/100
NO2 (nitrogen dioxide):
Good
5.3/100
O3 (ozone):
Fair
35.5/100
SO2 (sulfur dioxide):
Good
0.8/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
4.3/100
PM1 (ultrafine particles):
Good
7.1/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 16:00
AQI:
Medium
48.7/100
PM2.5 (fine particles):
Good
12.6/100
PM10 (coarse particles):
Good
4.1/100
NO2 (nitrogen dioxide):
Good
7.6/100
O3 (ozone):
Medium
48.7/100
SO2 (sulfur dioxide):
Good
1.3/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.7/100
PM1 (ultrafine particles):
Good
12.8/100
Pollen forecast in Winchester
View pollen forecastFrequently Asked Questions
Is air quality bad in Winchester right now?
On 16 July 2026, overall air quality in Winchester is fair. AQI is the main air quality indicator at 35.5/100. Pollution peaks around 2:00 PM (O3: 35.5/100).
Will air quality be worse tomorrow in Winchester?
On 17 July 2026, air quality conditions in Winchester will be better than today, with AQI forecast at medium at 48.7/100. Pollution peaks around 4:00 PM (O3: 48.7/100).
When is air pollution at its worst in Winchester?
Here's the thing about Winchester: air quality has a clear seasonal rhythm. Come summer, it's ozone rather than particulates that's the bigger concern, especially on still, sunny days. In deep winter, a lack of wind lets A55 traffic fumes and woodsmoke settle instead of blowing through. Spring and autumn don't usually cause much concern, sitting comfortably between winter's peak and summer's ozone spikes.
Are air quality levels in Winchester based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 CEST (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
For long term forecasts and maps, see the Airmine app