The humid and rainy weather has delayed hay fever misery but with a dry spell predicted to begin tomorrow, experts are warning sufferers to brace themselves for a pollen bomb.
And millions of asthmatics whose symptoms are triggered by hay fever are also being urged to be vigilant.
The increase in temperatures, combined with the thunderstorms predicted to take place next week, means pollen will be broken down into much smaller particles.
These are then inhaled more deeply into the lungs and can trigger a fatal reaction.
An estimated six million Britons are plagued by symptoms of hay fever every summer from itchy eyes, a constant runny nose, headaches to irritating sneezes.
And for half of them, fatal asthma attacks triggered by pollen, are a looming threat.
Beverley Adams-Groom is chief pollen forecaster at Worcester University which now works with the Met Office.
She told ITV News, grass pollen season is usually in full swing by now but has been delayed by the wet weather.
This month is already looking to be one of the wettest in recent years.
However, Ms Adams-Groom said this will change from tomorrow and Friday, warning hay fever sufferers should brace themselves for high pollen counts.
She said: ''London and the bulk of England will see temperatures in the high teens and early 20s. That's enough for high to very high pollen counts.
''We've had to wait for them this year - we would have had them from the beginning of June but we've had miserable, cold weather.''
Responding to reports of warmer weather and thunderstorms across the UK next week and the impact this will have on asthmatics, Colette Harris, Head of Health Advice at Asthma UK, said: “With grass pollen levels expected to rise mid-June as temperatures climb, and reports of potential thunderstorms brewing, this time could spell misery for the 3.3 million people whose asthma is triggered by hay fever.
''Pollen in the air sets off the allergic reaction that can inflame people’s airways, triggering asthma symptoms such as wheezing, coughing and at worst triggering a life-threatening asthma attack.
''Stormy weather breaks the pollen into much smaller particles, which are then inhaled more deeply into the lungs.''
What to do if you have hay fever:
- Allergy UK said the best way to avoid pollen is to keep windows and doors closed when inside - especially early in the morning and evening when the pollen count is highest
- They also advise avoiding peak pollen times and wearing wraparound sunglasses and a hat to prevent pollen getting onto the face and in the eyes.
- You should also avoid drying clothes on an outdoor washing line and shower when you get indoors to remove pollen from your skin and hair.
- Take antihistamines. They treat hay fever by blocking the action of the chemical histamine, which the body releases when it thinks it's under attack from an allergen. This stops the symptoms of the allergic reaction.
- Take corticosteroids (steroids) they are used to treat hay fever because they have an anti-inflammatory effect.
What to do if you suffer from pollen-related asthma:
- According to Asthma UK: 'If you have asthma and are already noticing more asthma symptoms because of hay fever, such as coughing, a tight chest or breathlessness, make sure you keep your blue reliever inhaler with you at all times.'
- Take hay fever medicines to help stop the allergic reaction.
- Use your preventer inhaler (usually brown) to soothe inflamed airways.