When is grass pollen season in UK? Dates of worst hay fever season for allergy sufferers - when it will end

Hay fever season in the UK lasts from March through to September, with different types of pollen occurring throughout the year

Wednesday, 16th June 2021, 2:52 pm
Updated Wednesday, 16th June 2021, 3:37 pm

Hay fever sufferers may have noticed symptoms kicking in over the last few weeks, as the UK is currently at the peak of its pollen season.

For those with allergies, the summer months will often be plagued by runny noses, sneezing and watering eyes, which can make venturing outside less than appealing.

But pollen levels are influenced by both season and location, with some parts of the country being worse affected than others and at different times of the year.

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Grass pollen season typically lasts from mid-May until July (Photo: Shutterstock)
Grass pollen season typically lasts from mid-May until July (Photo: Shutterstock)

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When is grass pollen season?

Hay fever season in the UK lasts from March through to September, with different types of pollen occurring throughout the year.

Tree pollen occurs first from around late March to mid-May, and affects around 25 per cent of people.

However, most hay fever sufferers are allergic to grass pollen, which has two different peaks.

The season typically lasts from mid-May until July, with the first peak usually starting in the first two weeks of June across England and Wales.

The second peak starts a little later in the first two weeks of July and will slowly tail off after this, giving way to weed pollen which occurs from the end of June through to September.

The peaks will be influenced by how wet, dry and hot the weather is, with the timing of the pollen seasons very much dependent on the weather during spring and early summer.

If temperatures are low in the winter, plants and trees will be dormant for longer heading into spring and less pollen will be produced.

A dry season will also minimise the amount of pollen produced, so a wet spring will benefit hay fever sufferers.

Can location influence hay fever symptoms?

The start of the season is influenced by where you live in the UK, with the north having a later start and a much shorter season.

Urban areas will have a lower pollen count than in the countryside, and places inland will typically have a much higher count than areas around the coast.

How does temperature affect the pollen count?

Heavy and prolonged rainfall early on in the day helps to keep pollen counts low all day, while rain in the afternoon will have less of an effect, so symptoms may still occur.

As temperatures are hot at the moment, it has caused more pollen to be released, exacerbating symptoms for allergy sufferers.

For grass, temperatures between 18 and 28C could produce a high pollen count if the weather remains dry with low humidity, while trees respond best when the temperature is between 13 and 15C.

If temperatures climb above 28C, all pollen levels will decrease, while several warm days in a row could result in pollen supply running out altogether.

The Met Office told NationalWorld: “We are seeing high and very high grass pollen counts in many places which will be having an impact on sufferers.

Weather doesn't in itself trigger hay fever symptoms, but it can help increase the pollen count. Different weather types have different influences on the pollen count.

“We are currently in the peak grass pollen season when we will see high, or very high, counts during any dry, warm weather.

“There are other species in flower too, such as some weeds, but the majority of hay fever sufferers are allergic to grass pollen.”

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