Forecast

In thermally favoured locations, the purple alder can cause stress!

Last week's weather conditions allowed the early bloomers to develop to a lesser extent than initially expected. Although significantly more catkins of the purple al der reached flowering readiness over the holidays, the conditions only allowed local pollen flight in thermally favoured locations.

As the weather forecast only rarely promises temperatures of 5 °C or more for the coming days, this trend will continue. However, as the sun is now able to fight its way through the cloud cover more often than in recent weeks, flowering purple alder and the associated stresses can be expected more and more frequently in sun-exposed locations and other thermally favoured locations.

During phenological observations in the field, the catkins of the more common alder species in Austria(grey and black alder) and those of tree and shrub hazels were still inconspicuous.

If we look at the forecast model for when hazel and alder are ready to flower across the whole area, we can currently expect flowering to begin between the end of January and the beginning of February.
However, these dates are still subject to a certain degree of uncertainty and are heavily dependent on the weather conditions in the coming days. The closer we get to the actual flowering period, the more precise the calculated data will be.

The team of the Austrian Pollen Information Service wishes you a happy new year!

Forecast date: 2025-12-30

Note: The data shown here are model data for the expected start of flowering. For more detailed information on the expected pollen count, please refer to the text forecasts.