According to the Pollen Bulletin from the Portuguese Society of Allergology and Clinical Immunology (SPAIC), all of mainland Portugal will face high pollen levels from 3 to 9 April. This mainly concerns pollen from cypress, plane, pine, birch, oak, cork oak, holm oak, grasses, nettles, and stinging nettles (including pellitory).

Data shows that Vila Real (Trás-os-Montes and Alto Douro region) will have high pollen levels from these trees and herbs. Porto (Entre Douro e Minho region) will also see high pollen, mainly from cypress, plane, pine, birch, oak, cork oak, grasses, and nettles (including pellitory).

In Coimbra (Beira Litoral region), the air will also be high in pollen from cypress, plane, pine, oak, cork oak, holm oak, grasses, sorrel, nettles, and pellitory.

In Castelo Branco (Beira Interior region), the atmospheric pollen concentration is predicted to be high, with a predominance of pollen grains from cypress, plane, pine, oak, cork oak, and holm oak trees, as well as grasses, sorrel, plantain, nettle, and nettles (including pellitory).

In the Lisbon and Setúbal regions, atmospheric pollen concentrations will also be high, especially from plane, pine, oak, cork oak, and holm oak trees, as well as grasses, sorrel, plantain, nettle, and pellitory (including nettle).

In Évora (Alentejo region), the atmospheric pollen concentration is also expected to remain high, predominantly from cypress, plane, pine, cork oak, and holm oak trees, as well as grasses, sorrel, plantain, nettle, and nettles (including pellitory).

In Faro (Algarve region), the atmospheric pollen concentration will similarly be high, with pollen from cypress, plane, pine, oak, cork oak, and holm oak trees, as well as grasses, sorrel, plantain, chenopodium, nettle, and nettles (including pellitory).

Conversely, the Autonomous Region of Madeira is expected to have a low concentration, predominantly from cypress and pine trees, as well as grasses, plantain, and nettles (including pellitory). The Autonomous Region of the Azores will also have a low level of atmospheric pollen concentration, with a predominance of plane tree, cypress (and/or cryptomeria), and grasses, nettles, and stinging nettles (including pellitory).