Last updated on 07/09/2019

What is Thunderstorm Asthma? Thunderstorm at night over a city

During grass pollen season people may notice an increase in asthma and hay fever. Grass pollen season (1 October through to 31 December) also brings the chance of thunderstorm asthma 

For those interested in the science – pollen grains from grasses get swept up in the wind and are carried for long distances; some burst open and release tiny particles that are concentrated in the wind gusts that come just before a thunderstorm. Typically, your nasal passages do a good job of trapping whole pollen when breathed in but in this unique situation, the small fragments bypass all the usual traps. These particles are small enough to be breathed deep into the lungs and can rapidly trigger asthma symptoms, making it difficult to breathe. 

Epidemic Thunderstorm Asthma was the phenomenon where many people, even those who had never experienced asthma before, developed asthma symptoms over a short period of time. It occurred due to an unusual combination of high grass pollen levels, dramatic change in weather conditions caused by a certain type of thunderstorm, which was the “perfect storm” of factors during peak hour in western suburban Melbourne. 

Epidemic Thunderstorm Asthma doesn’t happen often, but when it does the results can be severe. Southern states are more prone to seeing the unique factors come togetherIf you have asthma, you could experience a sudden, severe, and potentially fatal exacerbation 

Am I at risk of thunderstorm asthma?

If you have: 

  • Hay fever (seasonal allergic rhinitis) related to grass pollenwith or without asthma
  • Asthma (or a history of asthma)  
  • Undiagnosed asthma 

you are at increased risk. Having both poorly controlled asthma, and both asthma and hay fever increases the risk further.  

How can I prepare in advance?

There are several steps you can take to be prepared in advance Read our ‘Tips to prepare for thunderstorm asthma’ blog here.

Start the conversation with your GP and get checked 

The best defence is a good offense, and we encourage you to proactively check-in with your doctor about your asthma. If you think you might have symptoms of asthma or hay fever or if you experience wheezing or coughing with your hay fever (suggesting you may have both asthma and hay fever)see a doctor and get these symptoms checked. You can get a proper diagnosis and make sure you have the right medication and know how to use it properly this grass pollen season. 

Ask your doctor or pharmacist about a hay fever treatment plan and what you can do to help protect yourself from the risk of thunderstorm asthma. This may include having an asthma reliever puffer available – these are available from pharmacies without a prescription. 

If you develop asthma symptoms, follow the four steps of Asthma First Aid  and make sure you follow up with your doctor. 

Use your preventer 

We know the most important approach to managing and preventing asthma symptoms during spring and across the year involves using an appropriate inhaled preventer medicine. Asthma preventer medicines need to be tailored to each individual depending on their risks and symptoms and need to be used for around two to three weeks before they are effective at preventing symptoms and reducing sensitivity to triggers like pollen. So, if you aren’t already using one, the time to start is now. If prescribed a preventer, it needs to be used daily, and as prescribed, to maintain the anti-inflammatory benefit. 

Get an updated written Asthma Action Plan from your doctor which includes thunderstorm asthma 

Be prepared and have a plan for the medications you need to take and exactly when you need to take them, including what to do if you have an asthma flare-up. We have templates available on our website to make it easy.  

 If you have asthma, always carry your reliever with you  

Your reliever is your emergency asthma first aid medication. Don’t be without it.  

 If you have hay fever (seasonal allergic rhinitis) only, see your doctor or pharmacist 

Ask your doctor or pharmacist about the available treatments including intranasal corticosteroid sprays and make a hay fever treatment plan. It is also important you check you don’t have any suggestion of asthma and assess your specific risk of thunderstorm asthma. Plan what you need to do, which may include having an asthma reliever puffer appropriately available during grass pollen season (these are available from pharmacies without a prescription) and know how to use them properly, including Asthma First Aid. 

 Know the Asthma First Aid steps (and make sure your loved ones do, too!) 

Everyone should know the symptoms of asthma and what to do if someone is having an asthma attack.

 Download a pollen monitoring app 

Check out our pollen monitoring page for the best pollen monitoring stations and apps. Check them daily in pollen monitoring season so you know your local pollen count.  

 Avoid exposure where possible 

Where possible, avoid being outside during thunderstorms from October through December – especially in the wind gusts that come before the storm. Go inside and close your doors and windows, and if you have your air conditioner on, turn it to recirculate. Perhaps it’s time to sign up for Netflix?  

 You can also use the Bureau of Meteorology’s free weather radar to help you avoid storms, particularly if you’re planning on being outside or traveling on public transport during the grass pollen season.  

What if thunderstorm asthma strikes?

 In the event of thunderstorm asthma, if you develop asthma symptoms, follow your written Asthma Action Plan or use Asthma First Aid. In a medical emergency dial Triple Zero (000) for an ambulance. The most important thing is to listen to the Triple Zero (000) call taker – they will talk you through everything you need to do. 


Thank you to the Department of Health & Human Services Victoria for their assistance in the development of this article.  

Asthma Australia represents and supports the 2.7 million Australians living with asthma. To speak with an Asthma Educator call 1800 ASTHMA (1800 279 462).