According to forecasts from the Portuguese Society of Allergology and Clinical Immunology (SPAIC), until 22 May, the concentration of pollen in the air will be high in all districts of mainland Portugal, especially for olive, pine, birch, cork oak and oak trees and grasses, plantain, sorrel and nettle.

In the Autonomous Region of Madeira, forecasts indicate low concentrations of pollen in the atmosphere, particularly in cypress, pine, eucalyptus trees and also grasses, plantain and nettle.

In the Autonomous Region of the Azores, the concentration of pollen in the atmosphere is low, but with emphasis on cypress and pine trees and grasses, plantain and nettle.