When is weed pollen season, when does it start and what time of day has the highest pollen count in the UK?

WEED pollen season is the last of the three main pollen seasons - after tree and grass - that sufferers need to be aware of, but lasts at least up to late September.

Here's all the info you need to know.

When is the weed pollen season?

It mostly occurs between late June and September although weed pollens can be released at any time between early spring and late autumn.

Pollen counts – the amount of pollen in the air – can vary.

Symptoms normally appear when the count is above 50.

You may also have symptoms to only one type of weed pollen or to several, so when you experience symptoms will depend on which weed pollen you are allergic to and when it is released.

Pollen counts are usually higher on warmer dry days than cooler wet days as rain removes pollen from the air, and they won't be the same in every region, so where you live in the country can determine the severity of your symptoms.

The season in 2019 started three weeks early due to the warm winter which saw temperatures hit 21C in February and a generally warmer than usual spring.

Which pollens are released in the season and when?

• Dock – pollen released between late May and early August, peaking between late June and late July
• Mugwort – pollen released between late June and early September, peaking between late July and mid-August
• Nettle – pollen released between early May and late September, peaking between late June and early August
• Oilseed rape – pollen released between late March and late July, peaking between early May and late June
• Plaintain  – pollen released between early May and late August, peaking between early June and mid-July

Certain foods can also worsen the symptoms

What foods can make the reaction worse?

Some people will have a cross-reaction to their weed pollen allergy when they eat certain foods - this is known as oral allergy syndrome or pollen food syndrome.

This is due to the similarities in the proteins in the foods and the weed pollen.

While there will be differences depending on the pollen, the most common foods to avoid are:

• Melons
• Green peppers
• Carrots
• Celery
• Parnsip
• Sunflower seeds

Additionally, beer, wine and spirits contain histamine – the chemical responsible for allergy symptoms – so alcohol can make hay fever symptoms worse.

What time of day is worst for sufferers?

Pollen counts tend to be higher in early morning and late evening, although they can sometimes be high all day long.

If the grass is damp, the pollen peak will be later in the morning because the water evaporates before the pollen is released.

Pollen rises in the air during the day and then descends at night, as the air cools.

In rural areas, the evening peak tends to occur between 6pm and 9pm but in the city, where the air stays warmer for longer, the pollen descends later and levels tend to peak between 9pm and midnight or even later, which is why you may wake up sneezing in the night.

Sunny days favour higher pollen counts and rain tends to wash the pollen away, whereas on a cloudy day, pollen builds up only to be released on the next sunny day.