Have you noticed that a sudden change in weather can trigger your asthma symptoms?

Have you noticed that a sudden change in weather can trigger your asthma symptoms? If so you're not the only one. Cold weather, thunderstorms, hot weather, or sudden changes in temperature all trigger asthma symptoms for some people.

Hot weather

Hot weather can trigger asthma symptoms in some people. It’s not known why, but one theory is that breathing in hot air can cause the airways to narrow, leading to coughing and shortness of breath.

Another theory is that hot weather can increase the amount of pollutants and mould in the air - both can trigger asthma symptoms. And if both pollen and air pollution levels are high, you might experience what’s known as ‘grey fever’.

If it’s very hot:

  • Carry your blue reliever inhaler with you at all times and keep taking your regular preventer inhaler as prescribed by your doctor.
  • Don’t leave your inhalers in direct sunlight or anywhere they might get too hot, such as the glove compartment of your car or on a hot window sill. This will stop them working well.
  • If the pollen count is high and you're allergic to pollen, make sure you’re managing your hay fever well. Hay fever symptoms can make asthma symptoms worse for some people.
  • Avoid exercising outdoors during the hottest part of the day (11am-3pm).
  • Plan any outdoor activities for earlier in the day when the air quality tends to be better.
  • Drink lots of water to prevent you getting dehydrated.
  • When you're indoors, keep the doors and windows closed.

Find out the weather forecast for your local area.

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Thunderstorms can trigger asthma attacks in people with asthma, especially children and young adults. It’s not fully understood why this happens.

One reason could be that when it’s very humid, the windy conditions during a thunderstorm blow lots of pollen and mould spores high into the air. The moisture higher up in the air breaks them into much smaller pieces.

As these smaller pieces of pollen and mould particles then settle back down, they can be breathed in, irritating the smaller airways of the lungs. This can trigger asthma symptoms.

If a thunderstorm is forecast:

  • Stay indoors if you can, before, during and after the storm, and keep the windows closed.
  • Change your clothes and have a shower when you’ve been outside to wash off any pollen.
  • Avoid any of your other asthma triggers, such as exercise, alcohol or stress.
  • Have your reliever inhaler close by and ready to use if you need it.
  • If you have hay fever, take your usual hay fever treatments such as a nasal spray and/or antihistamines. If you’re not sure, speak to your pharmacist or GP about the best hay fever treatment for you.
  • Don’t smoke or let other people smoke around you because it can make asthma symptoms worse.
  • Make sure you know the signs that your asthma is getting worse and what you need to do if it is.

Cold weather

Why can cold weather increase your risk of asthma symptoms or an asthma attack?

Cold or damp air can enter the airways and trigger them to go into spasm, causing asthma symptom like coughing, wheezing, shortness of breath and tightness in the chest.

During cold, damp weather there are also more mould spores in the air, which can trigger asthma symptoms too.

And winter can be a difficult time for people with asthma for other reasons too. It's hard to avoid the cold and flu viruses that many people say make their asthma symptoms worse.  Being vaccinated against flu each year can prevent you getting the most common strain of flu virus.

If you avoid going outside in the winter because of the cold weather (as many people with asthma tell us they do), you may be exposed to more indoor air pollutants like dust mite droppings and fumes from cooking or cleaning products. You might even find that your symptoms are triggered by Christmas trees or dusty decorations.

How can you reduce winter’s effect on your asthma?

The best way to avoid cold weather triggering asthma symptoms is to manage your asthma well:

  • Carry your reliever inhaler with you at all times and keep taking your regular preventer inhaler as prescribed by your doctor.
  • Check with your GP or asthma nurse that you’re using your inhaler(s) correctly.
  • Use a written asthma action plan and keep it where you can see it (on the fridge, for example). You can also take a photo of it on your phone so you can refer to it whenever you need it.
  • Go for regular asthma reviews.
  • If you need to use your inhaler more often than usual, or use more puffs, speak to your doctor about reviewing your medication.

You can also try these practical tips:

  • Keep an eye on the weather forecast
  • If sudden changes in temperature - like stepping from a warm house onto a cold street - trigger your symptoms, try wrapping a scarf loosely over your nose and mouth before you go out. This will help to warm up the air before you breathe it in. And send us your #scarfie so we can spread the word!
  • Try breathing in through your nose instead of your mouth, to warm the air as you breathe it in.
  • You can find some useful advice about exercising in cold weather here.
  • Watch the video below for tips on how to help your child stay well with their asthma during winter. 

Tips for children with asthma in cold weather

Shakeela shares her tips for keeping her sons safe from the cold weather.

Video: Tips for children with asthma in cold weather

Shakeela shares her tips for keeping her sons safe from the cold weather.
Transcript for ‘Helping your child stay well with their asthma when it’s cold’

0:04 Salis is quite sensitive to the cold weather, so is Sami actually,

0:08 their asthma does get really bad with the cold weather.

0:11 I’ve just got to make sure they’re wrapped up well in winter

0:14 and their scarves are wrapped around their mouth and covering their nose

0:18 because, as they’re breathing the cold air, it can really set off their asthma,

0:23 and within minutes, they’re actually wheezing.

Related resources
Asthma and My Child booklet

Asthma and my child

This booklet explains how to help your child manage their asthma so they can get on with enjoying life.

Download (3 MB)


Last updated June 2019

Next review due November 2019

Asthma action plans keep all your personal triggers and medicines tips in one place. Download one now to fill in with your doctor or nurse.