Because of those conditions, Melbourne Pollen, the city’s air‑monitoring service, says the state is likely to see more extreme grass pollen days this spring. The grass pollen season officially begins on 1 October.

Last year Melbourne recorded five extreme and 15 high grass pollen days. “We are seeing conditions that look more favourable to a larger year than we did last year,” said Edwin Lampugnani, CEO of AirHealth, which runs Melbourne Pollen.

Satellite imagery now shows a noticeable increase in greenness over north‑western pasture lands, where most of the region’s rye grass is grown. This extra vegetation directly translates into higher pollen production.

Western and central Victoria are expected to register the highest pollen counts, while the Gippsland region, forecast to stay dry, should experience a quieter season. “In the Gippsland region … we’re expecting a subdued pollen season,” Lampugnani added.

When extreme pollen levels meet a thunderstorm, pollen grains can break into tiny particles that reach deep into the lungs – a phenomenon known as thunderstorm asthma. The 2016 Melbourne event, which killed nine people, is the most severe example.

The Department of Health will start issuing daily thunderstorm‑asthma forecasts through the Vic Emergency app, giving residents an early warning to prepare their medication and action plans.