Last day of spring, how's the grass pollen season going?

Nov. 30, 2022

Now that spring's over, what's summer looking like for grass pollen?

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Today’s the end of spring. Summer starts tomorrow and there’s only a month more left of 2022.

We’re expecting the grass pollen season will tail off towards the end of the year too.

So, how’s the season been so far in Melbourne?

In a word – average.

Today’s plot show the cumulative grass pollen curve for the 2022 season in dark blue. This is obtained by adding each day’s value to the sum of all previous days from October 1.

The green line is the 2021 cumulative grass pollen curve, and the dotted line is Melbourne’s 30 year average.

The 2022 season curve is slightly under the average season curve and well below the 2021 curve.

But while the total amount of grass pollen this year is slightly sub-par, the number of high and extreme grass pollen days is about average.

High and extreme grass pollen days are the worst days for people with hay fever and asthma, and so far this season we’ve seen 11 of these (eight high and three extreme). An average Melbourne season sees around 12 high and 8 extreme grass pollen days, with around 40% of this total coming in December.

It’s fair to ask why La Nina hasn’t delivered a bigger grass pollen season this year.

The reason is that, as well as being wet, this spring has also been cool, with maximum temperatures in Melbourne a degree below average, the lowest in 30 years.

The lower maximum temperatures are due to more southerly winds, which do not carry as much grass pollen as they come off the ocean rather than passing over pasture lands.

So, what’s the rest of the season looking like?

We’re expecting the average conditions will continue, which means we’re expecting another ten or so high and extreme grass pollen days before the end of the year.

In fact, we’re predicting there'll be seven high and extreme grass pollen days in Melbourne over the next ten days.

Download the Melbourne Pollen app to stay up-to-date with the latest pollen forecasts.

In our next update, we'll look at how the season is going in other parts of Victoria.

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