The mini heatwave has caused pollen levels to soar, causing misery for hay fever sufferers.
The recent hot spell, as well as muggy air, means there will be a "very high" pollen court this week in certain parts of the country, including the South West.
Met Office maps show "very high" pollen symbols across most of England, particularly in southern and central areas, reports Mirror Online .
Breathing in hot air can cause airways to narrow while warm weather can also increase the amount of pollutants in the air.
Dr Andy Whittamore, clinical lead for Asthma UK and a practising GP, said the humid air could potentially cause an asthma attack.
"This swampy humid air could spell misery for people with asthma and even trigger a potentially life-threatening asthma attack," he said.
"Humidity can trap pollutants and allergens like pollen, mould, dust and smoke in the air, which then cause asthma symptoms such as coughing, wheezing and a tight chest.
"If you have asthma and are already noticing more asthma symptoms 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) as prescribed to reduce the inflammation in your airways."
Some 10 million people in Britain suffer with hay fever - and it affects around 80% of people with asthma.
Grass pollen is the most common allergy and affects 90 per cent of people with hay fever, according to Allergy UK.
The season runs from mid-May until July, with two peaks - usually the first two weeks of June and the first two weeks of July.
Mirror Online said that, while temperatures become cooler this week , the weather will remain somewhat muggy.
