When does allergy season start?

The duration of the pollen season varies from year to year and from country to country1, and is likely to change in the future due to the influence of climate change2. Depending upon where you live and what you are allergic to, the pollen season may start as early as the end of February and last until the beginning of September3.

Allergy symptoms appearing in early spring can be attributed to hazel pollen or alder tree pollen, as they bloom at that particular time4. Birch pollen, elm tree pollen and oak tree pollen are the major irritants during late spring4. Grass, which is the most common cause of hay fever in Europe3, is the primary cause of allergy during midsummer5. At the end of summer, mug wort pollen can provoke allergy symptoms. Spores from fern, mushrooms and moss are also capable of provoking allergies (including contact dermatitis) or asthma6-8.

Allergy Calendar

Different types of allergens occur at different times of the year. The peak periods have been highlighted below:

tilt icon
  • jan
  • feb
  • mar
  • apr
  • may
  • jun
  • jul
  • aug
  • sep
  • oct
  • nov
  • dec

Tree pollen

Grass pollen

Weed pollen

House dust mites, mould, animal dander etc.


  • Smith M, Jager S, Berger U, Sikoparija B, Hallsdottir M, Sauliene I, et al. Geographic and temporal variations in pollen exposure across Europe. Allergy 2014; 69:913-23.
  • Lake IR, Jones NR, Agnew M, Goodess CM, Giorgi F, Hamaoui-Laguel L, et al. Climate Change and Future Pollen Allergy in Europe. Environ Health Perspect 2017; 125:385-91.
  • D’Amato G, Spieksma FT, Liccardi G, Jager S, Russo M, Kontou-Fili K, et al. Pollen-related allergy in Europe. Allergy 1998; 53:567-78.
  • Native and naturalized trees of Britain and Ireland. Available from http://www.first-nature.com/trees/index.php.
  • Annesi-Maesano I, Rouve S, Desqueyroux H, Jankovski R, Klossek JM, Thibaudon M, et al. Grass pollen counts, air pollution levels and allergic rhinitis severity. Int Arch Allergy Immunol 2012; 158:397-404.
  • Kofler H, Hemmer W, Focke M, Jarisch R. Fern allergy. Allergy 2000; 55:299-300.
  • Hayes JP, Rooney J. The prevalence of respiratory symptoms among mushroom workers in Ireland. Occup Med (Lond) 2014; 64:533-8.
  • Uter W, Schmidt E, Lessmann H, Schnuch A. Contact sensitization to tree moss (Evernia furfuracea extract, INCI) is heterogeneous. Contact Dermatitis 2012; 67:36-41.