The state's thunderstorm asthma risk forecasting system was turned on on Monday, with the system to run through to the end of December.

"We want everyone, particularly those with asthma or hay fever, to be as prepared as they can for the grass pollen season," chief health officer Dr Brett Sutton said.

"The best way to protect yourself from thunderstorm asthma is through good management of asthma and hay fever."

Read more: Bendigo Hospital is prepared for thunderstorm asthma event as spring pollen season hits

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.

The largest incident of unprecedented epidemic thunderstorm asthma in the world was in Victoria in November 2016, when thousands of people developed breathing difficulties in a very short period of time.

Nine people died and almost 13,000 people presented to Victorian public hospitals.

Dr Sutton said following the forecasting system can assist people to protect themselves, but shouldn't replace good asthma and hay fever care.

Read more: Thunderstorm asthma warning issued for parts central Victoria

"Those at risk should always follow their asthma or hay fever treatment plan," he said.

"Where possible, people with asthma and hay fever should also avoid exposure to springtime thunderstorms, especially the wind gusts that precede them."

Epidemic thunderstorm asthma risk forecasts are available on the VicEmergency app and at emergency.vic.gov.au/prepare/#thunderstorm-asthma-forecast

Pollen observations and forecasts in Bendigo are available at melbournepollen.com.au and via the Melbourne Pollen Count App.

Have you signed up to the Bendigo Advertiser's daily newsletter and breaking news emails? You can register below and make sure you are up to date with everything that's happening in central Victoria.