Situation and medium-term forecast for

Issued 22nd of April 2021

Situation and medium-term forecast

Favorable weather conditions will result in a peak of the birch pollen season!

The weather forecast for this weekend promises sunshine and temperatures above 15°C and therefore ideal conditions for pollination. Due to the unfavorable conditions during the first half of April many plants reached readiness to flower but had no chance to start pollination properly. Therefore, a rapid increase of allergenic burden has to be expected during the next days.

For this weekend a peak of the birch pollen season with high to very high burden is expected. This is caused by the delay of plant development due to the rather bad weather conditions of the last weeks. Now the majority of plants reached readiness to flower and start pollination simultaneously. This year’s birch pollen season is expected to be less intense than the last one so the peak will cause intense burden but only for a short time.

Pollen from hornbeam, hop hornbeam and oak are recorded at our monitoring stations as well. They will increase the allergenic burden for some birch pollen allergy sufferers even further, due to cross reaction.

Ash passed its peak pollination period already but will still cause low to moderate burden.

Plane trees are now in full bloom. Pollen allergy sufferers that are sensitized for this pollen type may experience allergenic burden in vicinity to avenues of plane trees.

The forecast data for the next phase of the pollen season, the readiness to flower for grasses, indicate a start for the beginning of May. This indicates an average start of the grass pollen season from a current point of view.

What else: The pollen spectrum contains pollen from yews, cypresses, poplar, maple, willow and walnut in addition, which is of a low allergological importance.


We expect the readiness to flower for grasses inon
St. Pölten12.05.2021

Forecast from 22.04.2021
Note: The model results give an indication of the expected start of flowering, based on information provided by local pollen warning services with direct reference to the local situation. Readiness to flowering is not equal to the beginning of the pollen season. When the start of flowering is achieved, most of the plants can release pollen, but only when weather conditions are favourable.

Responsible for the content: and the Department of Oto-Rhino-Laryngology of the Medical University Vienna, Research group aerobiology and pollen information
Uwe E. Berger MBA, Mag. Maximilian Bastl PhD and Mag. Dr. Johannes Bouchal
medium-term forecast based on model and pollen data from Austria and surrounding countries
reprint and publication in parts or completely is permitted only quoting the source

weather data and today´s forecasts based synoptic data: ZAMG (Zentralanstalt für Meteorologie und Geodynamik)
zum Team

The current pollen load for Austria

Legende: 1 = Low, 2 = Moderate, 3 = High, 4 = Very High

birch (Betula)

Friday, 23. April
Saturday, 24. April
Sunday, 25. April

ash (Fraxinus)

Friday, 23. April
Saturday, 24. April
Sunday, 25. April

plane tree (Platanus)

Friday, 23. April
Saturday, 24. April
Sunday, 25. April
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