Pollen Count Forecast

A pollen allergy is an immune response to grass, tree, or weed pollen. Individuals who are allergic to pollen may experience symptoms such as sneezing, itchy eyes, and a runny nose when the pollen count is high (commonly referred to as hay fever symptoms).

The pollen count is measured by the Universal Pollen Index, which serves as the basis of the Pharmica Pollen Count Forecast tool.

This index measures the amount of pollen in the air, originating from 15 different plant species known to release pollen that can cause allergic reactions in those who experience hay fever.

According to the Met Office, a high pollen count is characterised by 50 to 150 grains of grass pollen or 81 to 200 grains of birch (tree) pollen per cubic metre of air.

Hay fever season typically starts at the beginning of spring when sunnier weather and rising temperatures trigger the release of pollen from various species of plants.

In the southern parts of the UK, hay fever season typically begins earlier in the year (usually March or April) than in the northern parts of the UK. This is because areas in the south normally experience warmer and sunnier conditions sooner than areas in the north, although the exact timing can vary every year depending on how wet, dry, warm or cold the weather is.

In the UK, the pollen count is strongest between the middle of spring and throughout summer (typically between May and July), although the exact months can vary because astronomical seasons can change every year, based on the position of the Earth’s orbit in relation to the sun.

In 2024, the pollen count is likely to be strongest between April and June as per the Met Office’s astronomical spring forecast.

The overall pollen count is likely to go down by September, however, each type of pollen has its own season. For instance, the tree pollen count typically begins to decrease by the end of May, while the grass pollen count normally goes down by the end of July and the weed pollen count can remain high until September.