What is thunderstorm asthma?

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

Thunderstorm asthma is thought to be triggered by a unique combination of high amounts of grass pollen in the air and a certain type of thunderstorm. For people who have asthma or hay fever this can trigger severe asthma symptoms. 

When a large number of people develop asthma symptoms over a short period of time, related to high grass pollen and a certain type of thunderstorm,  it is known as epidemic thunderstorm asthma

Maps of current epidemic thunderstorm asthma forecast


Map of Victorian weather districts and the status for today. These details are available in the table above or at emergency.vic.gov.au


Map of Victorian weather districts and the status for tomorrow. These details are available in the table above or at emergency.vic.gov.au

Forecasts are issued twice daily during the grass pollen season (October to December). They cover three consecutive days and use a colour-coded scale: green (low), orange (moderate) and red (high).

For up to date information on epidemic thunderstorm asthma risk visit the VicEmergency website or download the VicEmergency app from Google Play or the App Store and set up a 'watch zone'.

In your language

በነጐድጓድ ዝናብ የሚከሰት አስም (Amharic) •  ربوعاصف الرعدية (Arabic)  • ܣܘܪܝܬ/Sūreṯ (Assyrian) • বাংলা (Bengali) • မုန်တိုင်း ပန်းနာရောဂါ (Burmese) • 风暴性哮喘 (Chinese (Simplified)) •  雷暴哮喘 (Chinese (Traditional)) • Astma uslijed grmljavinske oluje (Croatian)  •  آسم ناشی از توفان رعد و برق (Dari)  •  Tuaany pɔ̈t de piɔ̈u (Dinka)  •  آسم ناشی از طوفان و رعد و برق (Farsi)  •  Καταιγίδα άσθματος (Greek)  •  થડરસ્ટોર્મ અસ્થમા (Gujarati)  •  हिन्दी (Hindi)  •  Asma badai (Indonesian)  •  Asma da temporale (Italian)  •  ကညီကျိာ် (Karen) • • ជំងឺហឺតបងដោយយព្យុះផ្គររន្ទះ (Khmer)  •  تەنگەنەفەسی)ڕەبۆی( پاش بۆرانی بروسکاوی (Kurdish)  •  Астма при бура (Macedonian)  •  AdhumƐ thuɔ̱ɔ̱l nhial (Nuer)  •  Astma burzowa (Polish) •  ਥੰਡਰਸਟੋਰਮ ਅਸਥਮਾ (Punjabi) Грозовая астма (Russian)  •  Астма за време непогоде (Serbian)  • සිංහල (Sinhalese)  • Neefta danabka dabaysha (Somali)  •  Asma de las tormentas eléctricas  (Spanish)  • Unos na hika (Tagalog)ஆஸ்துமா (Tamil)  •  اردو (Urdu)  •  Hen suyễn do giông bão (Vietnamese)

View an accessible version of this video or read the transcript

Who is at risk?

Thunderstorm asthma can affect those with asthma or hay fever - especially people who experience wheezing or coughing with their hay fever.   

Even if you don't think you have asthma or hay fever, don't ignore symptoms like wheezing or shortness of breath - check with your GP.

Learn more about asthma and hay fever.   

Protect yourself this pollen season

Here are some things you can do to prepare for pollen season:

  • If you have asthma – your GP can help you develop or update your asthma action plan to manage your asthma.
  • If you've ever had asthma – talk to your GP about what you can do to help protect yourself from the risk of thunderstorm asthma this pollen season. Remember, taking an asthma preventer properly and regularly is key to preventing asthma, including thunderstorm asthma.
  • If you experience wheezing, shortness of breath, chest tightness or a persistent cough then you may have asthma. It’s important you talk to your GP and get it checked out. 
  • If you have hay fever – see your pharmacist or GP for a hay fever treatment plan.
  • If you have hay fever, and especially if you experience symptoms of asthma, such as wheezing, shortness of breath, a tight feeling in your chest or coughing, it is important to make sure you don’t also have asthma. Speak to your GP today about whether you might also have asthma, and check if you should have an asthma reliever puffer – which is available from a pharmacy without a prescription.

And finally, 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. If you have your air conditioning on, turn it onto recirculate.

If you develop asthma symptoms, follow your asthma action plan, or if you don’t have one yet, follow the four steps of asthma first aid.

Download the Vic Emergency app (App Store or Google Play) and set up a 'watch zone' for your location to receive advice and warnings about potential epidemic thunderstorm asthma events during the grass pollen season. You can also visit the Vic Emergency thunderstorm asthma webpage for updates and information.

Learn asthma first aid

It's important for everyone in the community to know the four steps of asthma first aid so they know what to do if they or someone is having an asthma attack.