Hay fever starting early this year due to warm weather

Due to the exceptionally warm start of the year, people may get hay fever complaints earlier than usual. According to Wageningen University and the Leiden University Medical Center (LUMC), birches in the Netherlands will start blooming this week due to the sunny and warm spring weather. "The birch spreads highly allergenic pollen and can cause many complaints in people with an allergy to birch pollen," said the LUMC.

Because no significant rain is forecast for the coming period, the amount of pollen in the air is increasing. Some people can develop symptoms even with low amounts of birch pollen, according to the researchers. "It is good for these people to know that birch pollen can appear unusually early this year. We recommend that people with a birch pollen allergy start their medication in good time."

The universities anticipate that the peak of the birch pollen season will fall between the end of March and April 18 this year. During this period, the most birch pollen occurs in the air during dry weather.

Wageningen University established that trees such as chestnut, mountain ash and hawthorn are also developing leaves three to four weeks earlier than normal due to the high temperatures. Sweet violets, celandine, wood anemone and the first cuckoo flowers, also known as mayflowers, are already in full bloom a month earlier than usual. Fifty years ago, trees such as the horse-chestnut and the poplar did not get their first leaves until the end of April or the beginning of May. It was just a bit earlier in 2020, according to the university.

People who are only allergic to grass pollen will not have hay fever complaints just yet. "The sun and heat will make the grass grow, but not yet bloom," the researchers said. The peak of the grass pollen season is on average at the end of May and in June.