(Vienna, 31 March 2025) Allergy sufferers can expect birch pollen at the Vienna City Marathon (VCM) next Sunday, April 6, 2025. The birch reaches its peak flowering period at the weekend. Ash and, to a certain extent, hornbeam also still play a role.
Birch, which is normally the main allergen for April, has only started flowering hesitantly this year due to unstable weather, but will have reached its peak flowering period by the running weekend, which means that pollen release must be expected in any case. In spring-like weather conditions without precipitation, birch pollen concentrations could also be very high on the 2025 running weekend in Vienna.
Ash tree reaches the end of its main flowering period
The ash trees have started to flower at the long-term average and are above average in their intensity this year. Even though some of the ash trees have already finished flowering and the main pollination period is coming to an end, relevant pollen concentrations can still be expected over the weekend.
Cross-reactions can intensify allergic symptoms
Another plant with allergenic potential that is currently playing a role in the pollen spectrum is hornbeam. As a member of the birch family, it is closely related to hazel, alder and birch and can additionally irritate allergy sufferers who are sensitized to birch pollen. The hornbeam has already reached higher pollen concentrations than the usual average at the end of March and is currently also in its peak flowering period.
No trace of grasses and other cross-allergens
Due to the recurring cold spells and the early date of this year's Vienna City Marathon, no additional allergenic pollen is expected in the air. Oak, beech and plane trees have not yet started to flower, and the grasses will not yet be an issue on the running weekend either. The early flowering hazel and alder have already finished blooming.
Once again this year, MedUni Vienna's Pollen Service Vienna is offering a detailed pollen forecast for the Vienna City Marathon, as well as tips and tricks for preparing before, during and after the run. In addition, informative graphics with schematic representations of the increased occurrence of relevant allergenic plants along the running course are available, which were created in collaboration with the VCM team.
The pollen forecast will be updated on Thursday, April 3, 2025, at www.pollenservice.wien to provide details and the forecast weather conditions.
Maximilian Bastl from MedUni Vienna's Pollen Service Vienna recommends: "Runners at the VCM should make preparations for this year's pollen concentrations if they are affected by a pollen allergy. In dry and spring-like weather conditions, which promote the pollen count, it is advisable to take preventative medication. During the run, headgear and sunglasses can be worn to reduce contact with pollen."
Further information
Allergenic plants along the running route - Homepage of the VCM
Website Pollenservice Vienna: www.pollenservice.wien