Weather

How to stay well if weather triggers your asthma symptoms – whether it’s cold air, summer heat or thunderstorms

Not only can extremes of heat and cold trigger people’s asthma, even sudden changes in temperature can cause symptoms to flare up.

On this page:

Hot weather

Thunderstorms

Changes in weather

Cold weather

Hot weather

Mostly we think of asthma symptoms being worse in the winter. But hot summer weather can trigger asthma symptoms for some people too.

The causes are not clear but two possible reasons are:

  • Breathing in hot air can cause the airways to narrow, leading to coughing and shortness of breath.
  • When it’s hot in summer, there are often higher levels of pollutants and pollens in the air. 

Top tips if hot weather sets off your asthma

  • Keep taking your regular preventer inhaler so you’re less likely to get symptoms. And carry your reliever inhaler with you at all times so you’re ready if symptoms do come on.
  • Use a written asthma action plan so you know what to do if hot weather triggers symptoms
  • Go for regular asthma reviews to check you’re on the right meds for you, and you’re taking your inhalers in the best way to get the benefits through the summer months
  • If you’re using your reliever inhaler three or more times a week, or you’ve noticed the hot weather’s made your symptoms worse, book an extra catch up with your doctor or asthma nurse.
  • Keep inhalers in a cool place out of direct sunlight so they continue to work well. Try keeping your reliever in a cool bag when you’re out and about on a hot day.
  • Keep an eye on pollen forecasts and find out more about why staying on top of your hay fever symptoms with antihistamines is good for your asthma too.  
  • Plan any outdoor activities for earlier in the day when the air quality tends to be better, including exercise.

Thunderstorms

Thunderstorms can be an asthma trigger. Two possible reasons for this are: 

  • The air before a storm can feel very humid and close. Some people tell us this gives them a tight chest and a cough, and that they find it harder to breathe.
  • During pollen season, the windy conditions during a thunderstorm blow lots of pollen high into the air. The moisture higher up in the air breaks the pollen into much smaller pieces. As these smaller pieces of pollen particles then settle back down, they can be breathed in, irritating the smaller airways of the lungs.

Top tips if thunderstorms set off your asthma

  • Keep taking your regular preventer inhaler so you’re less likely to get symptoms. And carry your reliever inhaler with you at all times so you’re ready if symptoms do come on.
  • Use a written asthma action plan so you know what to do if a thunderstorm is forecast or triggers symptoms
  • Go for regular asthma reviews to check you’re on the right medicines for you, and you’re taking your inhalers in the best way to get the benefits.
  • If you’re using your reliever inhaler three or more times a week, or you’ve noticed pollen or thunderstorms make your symptoms worse, book an extra catch up with your doctor or asthma nurse. 
  • If you know thunderstorms affect you, try staying indoors before, during and after the storm, and keep the windows closed to stop released pollen getting indoors.
  • Take your usual hay fever treatments such as a nasal spray and/or antihistamines during your pollen season

Changes in weather

“One of my main triggers is a change in the weather, whether this is an increase or decrease in temperature.  When this happens my chest becomes tight, I begin to cough and have to use my reliever inhaler.” Monica, age 66

Top tips to deal with symptoms when the weather changes

“Our weather in the UK is unpredictable and changes happen suddenly sometimes. So it’s important to stick to a good routine of taking your preventer inhaler every day as prescribed,”  says Dr Andy Whittamore. ‘That way you’re on top of your asthma whatever the UK weather throws at you.”

  • Keep taking your regular preventer inhaler so you’re less likely to get symptoms. And carry your reliever inhaler with you at all times so you’re ready if symptoms do come on.
  • Use a written asthma action plan so you know what to do if changes in the weather trigger asthma symptoms
  • Go for regular asthma reviews to check you’re on the right medicines for you, and you’re taking your inhalers in the best way to get the benefits, whatever the weather.
  • If you’re using your reliever inhaler three or more times a week, or you’ve noticed weather changes making your symptoms worse, book an extra catch up with your doctor or asthma nurse. 
  • Keep an eye on the weather forecast so you’re prepared for changes coming up.
  • Make sure you know the signs that your asthma is getting worse and what you need to do if it is.
  • Carry a small scarf around with you to go over your nose and mouth so you’re prepared if the weather turns windy or cold.

Cold weather

When it gets colder, you may notice that your asthma symptoms get worse. If this happens to you, you might dread winter every year. Read on to find out how to manage this common asthma trigger.

What can I do if my asthma is triggered by cold air?

Keep taking your regular preventer inhaler, so you’re less likely to get symptoms

Carry your reliever inhaler with you at all times, so you’re ready if symptoms do come on.

Use a written asthma action plan, so you know what to do if cold weather sets off your asthma symptoms

Go for regular asthma reviews. This will help ensure you have the right medicine and pick up on any signs you may be at risk of an asthma attack over winter.

Before you head out in the cold, try wrapping a scarf loosely around your nose and mouth. This stops your airways getting a shock of cold air, which can trigger asthma symptoms.

You could also try breathing in through your nose instead of your mouth, if you can, as this also warms up the air as you breathe it in.

Why does cold weather make my asthma worse? 

When it’s cold, the air is colder and drier 

Breathing in dry, cold air irritates your airways. Your lungs then react to this by becoming tighter and this makes it more difficult to breathe.

Our bodies are designed to respond to changes in air temperature. However, some people are more sensitive to changes in temperature and may have a stronger reaction, which includes asthma symptoms that are set off by cold air. The good news is, your asthma is less likely to be triggered by cold weather if it’s well controlled.

You can also help yourself by trying to breathe through your nose more, rather than just your mouth. This is because when you breathe through your nose, cold air is warmed up by passing through your nose, throat and then your upper airways. If you just breathe through your mouth, this warming up process doesn’t happen, which means the cold air dries out the moisture in your lungs.

Cold air makes you produce more mucus

When it’s cold, you might produce more mucus than you normally would.

This is because when cold air enters your nose, the vessels in your nasal cavity get bigger and congested, which causes more mucus to be produced. This extra mucus is produced because your body is trying to create perfect conditions, by adding warmth and humidity, while also filtering the air that’s going into your body. This extra mucus is why you can get a runny nose in winter.

Mucus that you cough up from your lungs is called phlegm and coughing up more of it can be a sign that your airways are inflamed. We’ve got more advice on what you can do about this on our phlegm, mucus and asthma page.  

Cold weather brings colds and flu

Your body can also produce thicker mucus when you have a virus, such as a cold or the flu. These are more common during the colder months and are a top trigger for people with asthma - 75% of people with asthma say colds and flu set off their symptoms.

Cold weather forces us indoors 

When it’s cold, you’re also more likely to be indoors more, which means you’re more exposed to lots of indoor triggers. These include:

However, there are lots of things you can do to help keep these at bay, such as opening windows, using extractor fans and not using aerosols or sprays. You can find out more about ways to protect yourself on our indoor triggers page

How can I look after my child’s asthma when it’s cold?

Asthma nurse specialist Debby Waddell gives her 3 top tips:

    1. “Give your child a scarf to wear scarf loosely over their nose and mouth. It warms up the air they’re breathing in, so they’re less likely to get asthma symptoms.”

    2. “Talk to teachers about your child’s asthma triggers, including cold weather. Make sure your give the school a named spare reliever inhaler and spacer for your child to use if their asthma symptoms come on at playtime or during PE.

    3. “Most important of all, stick to your child’s preventer routine, and follow their written asthma action plan, so you’re staying on top of their asthma during the winter months. If their asthma is well controlled, your child is less likely to react to cold weather. And don’t forget to carry their reliever inhaler with you all the time, so you can act quickly if cold weather triggers their asthma.”

Understanding your personal weather triggers

“Both my mum and me have asthma, and the weather affects us in completely different ways. My mum’s asthma is not good when it’s cold and windy; mine is triggered when it’s warm and air quality is less good.” Charlotte, Asthma UK volunteer.

“The key thing is getting to know what your weather triggers are,” says Dr Andy. “Talk to your doctor so you can add them to your asthma action plan. And try keeping a symptom diary too - you may notice you’re more likely to react to the weather when there’s other things going on too, like hay fever, colds and viruses, or bad pollution.”

‘If you know weather is a trigger, especially changing weather, then have your reliever inhaler with you at all times and stick to your routine of taking your preventer inhaler to cut your risk of symptoms.”

Last updated December 2020

Next review due December 2023 

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.

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