Pollen Calendar
A generalised pollen calendar can be developed from historical pollen count records to show when the main allergenic plants are likely to be in flower. These times will differ according to geographical location and height above sea level. The exact timing and severity of the pollen seasons will differ from year to year depending on the weather and on various biological factors.
Tree pollen forecasts
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2nd of April until the 20th of May
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Grass pollen forecasts
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24th of May until the 5th of August
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Weed pollen forecasts
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6th of August until the 26th of August
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Fungal spore pollen forecasts
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27th of August until the 30th of November
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Grass pollen is the main cause of hayfever in the UK and affects 95% of sufferers. There are many types of grass pollen and because of difficulty of identifying one from another, all grass pollens are grouped together.
Pollen Forecasts
The Pollen Count is calculated by measuring the actual levels of pollen ‘grains’ per cubic metre of air and the data is gathered from pollen stations throughout the UK.
The pollen index is supplied through the National Pollen Network, and daily forecasts of anticipated pollen levels are made available. The index changes emphasis slightly during the season to reflect these various types of pollen and the pollen calendar guide above indicates the general spread of pollen release.
Pollen forecasts are calculated using gathered information, as well as local vegetation distribution, weather patterns and weather forecasts. The pollen forecast is usually given as LOW, MODERATE, HIGH or VERY HIGH. In the case of grass, LOW is less than 30 grains per cubic metre of air, MODERATE 30 to 49, HIGH 50 to 149 and VERY HIGH 150 or more.
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