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Key points
- Thunderstorm asthma is triggered by high pollen levels and thunderstorms.
- The condition is rare but can be sudden, serious and life-threatening.
- Thunderstorm asthma is more likely to affect children with asthma or hay fever, but any child can get it.
- Watch the pollen count and thunderstorm asthma forecast during the spring.
- If the forecast predicts thunderstorm asthma conditions, try to keep your child inside, close your doors and windows and set your air conditioner to recycle air when in use.
- Be alert for signs of asthma, such as difficulty breathing, tightness in the chest, wheezing and coughing.
- If your child has asthma, follow their Asthma Action Plan.
- Call an ambulance (000) immediately if your child struggles to breathe or talk.
What is thunderstorm asthma?
Thunderstorm asthma is a type of asthma caused by high pollen levels and thunderstorms. It is not common but can be sudden, serious and life-threatening.
The airways tighten or swell during an asthma attack, making it hard to breathe.
Your child may be at risk of thunderstorm asthma if they have asthma or seasonal allergies like hay fever (allergic rhinitis). People
who have never had asthma before can also get thunderstorm asthma.
What causes thunderstorm asthma?
During a thunderstorm asthma event, storm clouds draw in pollen as they form. The pollen grains suck up water from the clouds, causing them to swell and break into tiny particles pushed to ground level by wind and rain. People sensitive to pollen may
get asthma when they breathe in these particles.
Thunderstorm asthma pollen can get deeper into the lungs than regular pollen, leading to more serious symptoms more quickly.
It is important to note that not all thunderstorms cause thunderstorm asthma – even when the pollen count is high.
Signs and symptoms of thunderstorm asthma
Signs of thunderstorm asthma in children can include:
- Trouble breathing
- Tightness in chest
- Coughing
- Wheezing
- Struggling to talk in sentences.
In a serious case of thunderstorm asthma, your child may:
- become very upset, tired or limp
- make deep sucking movements in their throat or chest as they try to breathe.
Call an ambulance (000) immediately if your child struggles to breathe or talk.
Figure one: Graphic with advice on preparing for thunderstorm asthma, for families with hay fever and asthma.
Preparing for thunderstorm asthma
If you live in a high-pollen area and your child has asthma, hay fever or an allergy to pollen, you should prepare for thunderstorm asthma. A family history of asthma and allergies also increases the risk of the condition.
In Victoria, the most common times of year for thunderstorm asthma are spring and summer, between October and December. This is the state’s grass pollen season. If your child is at risk, it is a good idea to check the weather at this time of year before
they go outside. Not all thunderstorms on high-pollen days will trigger thunderstorm asthma; be ready but not alarmed.
The VicEmergency website shares a thunderstorm asthma forecast during these months, with warnings for each region of Victoria. You can also check Melbourne Pollen for the daily pollen forecast.
If the forecast predicts thunderstorm asthma conditions:
- try to keep your child inside – especially if it is windy
- close your doors and windows
- set your car or home air conditioner to recycle air when in use.
Advice for children with hay fever and allergies
- Check pollen levels daily during spring.
- Try to keep your child inside with doors and windows shut on high-pollen days.
- Talk about hay fever treatments with your child’s doctor; they may suggest a hay fever treatment plan and medicine.
- Watch your child closely on forecast thunderstorm asthma days.
- Call an ambulance (000) immediately if your child struggles to breathe or talk.
Advice for children with asthma
- Check your child’s Asthma Action Plan each year with a doctor.
- Make sure everyone who cares for your child has an up-to-date copy or photo of the Asthma Action Plan, including parents, grandparents and carers.
- Have a supply of your child’s asthma reliever medicine ready.
- Practice using an asthma reliever with a spacer so you are prepared to help. Children under four should use an asthma spacer with a mask.
- If your child has a preventer, make sure they use it every day during the grass pollen season – even when they are feeling well.
- Learn asthma first aid and call an ambulance (000) immediately in an emergency.
When to get help
Call an ambulance (000) if:
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- your child is struggling to breathe.
- your child is blue around the lips, drowsy or having trouble talking in sentences.
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Go to a hospital if:
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- your child is very upset, tired or limp with breathing that is fast or noisy.
- your child makes deep sucking movements in their throat or chest as they breathe.
- your child needs to use asthma reliever medicine at home more than every three hours.
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See a doctor or health professional if:
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- your child is working harder to breathe than normal.
- your child has symptoms of thunderstorm asthma, but they do not have a hay fever treatment plan or an Asthma Action Plan.
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Look after your child at home if:
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- they have a hay fever treatment plan or an Asthma Actin Plan that is helping to manage their symptoms.
- their symptoms get better when they stay indoors on high-pollen days.
- they only need to use their asthma reliever medicine every three to four hours and are otherwise well.
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Common questions about thunderstorm asthma
Can my child get thunderstorm asthma if they have never had asthma before?
Yes, your child can get thunderstorm asthma if they have never had asthma before. If your child has hay fever or a family history of asthma, their risk is higher. However, thunderstorm asthma can affect any child.
How is thunderstorm asthma different to normal asthma?
Thunderstorm asthma and normal asthma usually have the same symptoms but are caused by different things. A mix of pollen and weather conditions causes thunderstorm asthma; it comes on quicker and can be more severe than normal asthma.
Who is most likely to get thunderstorm asthma?
People with hay fever are the most likely to get thunderstorm asthma. However, some people with severe hay fever do not get thunderstorm asthma, and some people with thunderstorm asthma do not have hay fever.
My child is wheezing for the first time and I think it is thunderstorm asthma. What should I do?
If your child is wheezing for the first time on a day with forecast thunderstorm asthma conditions, you should speak with a health professional such as a pharmacist or your child’s doctor. A pharmacist can suggest treatment for their symptoms
and advise when you should speak with a doctor or take your child to hospital.
How do I know when there is a chance of thunderstorm asthma?
The Department of Health and the Bureau of Meteorology share a thunderstorm asthma forecast for Victoria between October and December. It is worked out by combining the chance of a certain type of thunderstorm with the predicted grass pollen levels.
If you live in Victoria, check this forecast to see if there is a chance of thunderstorm asthma conditions.
What happened during the thunderstorm asthma epidemic in 2016?
Melbourne was home to the world’s largest and most serious epidemic thunderstorm asthma event in November 2016. The Victorian Government has since invested money into improving the state’s pollen monitoring system and launched the Epidemic Thunderstorm
Asthma Risk Forecasting System to predict thunderstorm asthma.
For more information
Developed by The Royal Children’s Hospital Emergency department, with input from General Medicine. We acknowledge the input of RCH consumers and carers.
Reviewed September 2025
Please always seek the most recent advice from a registered and practising clinician.