Pollen in the canton of Basel-City
Four-day pollen forecast for the canton of Basel-City — 3 municipalities, from 268 to 492 m, in the Rhine valley region. Six pollens are tracked: alder, birch, grasses, mugwort, olive and ragweed. The reading is recomputed every night.
In the canton of Basel-City, 1 pollens are in the air today. Highest: Mugwort (low).
The next four days
Mugwort, hour by hour
Today and tomorrow, in grains per m³; dashed lines: low, moderate, high thresholds.
The season, month by month
Usual periods in Switzerland, shifted by one to three weeks depending on year and altitude; current month outlined.
Concentrations modelled by the European CAMS service via Open-Meteo, in grains per cubic metre of air, for a representative point of the canton. These are model values, not pollen-trap readings: for a diagnosis, an allergist remains the reference. Updated on 27.09.2026.
Pollen and altitude in the canton of Basel-City
Altitude shifts the season: in spring, flowering climbs about 100 metres every two to three days. In the canton of Basel-City, which ranges from 268 to 492 m, birch can be over in the valley while it is only starting higher up — a gap reaching 6 days between the canton's lowest and highest points.
It is also why going up often brings relief: above 1,500 metres grass concentrations drop sharply, and above 2,000 metres the season shrinks to a few weeks.
What to do when concentrations rise
- Air the rooms early in the morning or after rain. Concentrations peak in the late morning and early evening in dry, windy weather.
- Wash your hair in the evening: it traps grains and releases them onto the pillow.
- Drive with the windows closed, and change the cabin filter in spring.
- Rain washes the air — but a thunderstorm can shatter grass grains and trigger asthma attacks within the hour.
- Preventive treatment starts before the peak, not during it. That is the whole point of a four-day forecast.
See also
The canton's weather and radar:
Do these figures come from a sensor in the canton of Basel-City?
No. They are concentrations modelled by the European CAMS service, computed for a representative point of the canton. They give the trend and the level, not a local reading. Swiss pollen traps are operated by MeteoSwiss and aha! Swiss Allergy Centre.
Why are some pollens missing from the table?
A pollen only appears if it shows up on at least one of the four days. Six rows of zeros in October would tell nobody anything.
How often is the page updated?
Every night, along with the forecasts on the 12,000 pages of the site. The date is shown under the table.