Ask A Met: Can Weather Make Pollen Worse?

This week's question comes from Morning Brief reader Alex, who asks, "Can weather make pollen worse?"

Meteorologist Sara Tonks: The right weather can absolutely make pollen conditions worse.

It's dependent on what the plants are doing and when the plants start producing pollen.

When you have a mild winter, that lets the plants get in a temperature range where they can start producing pollen much earlier and so you get pollen earlier in the year.

When you have winter starting later, you have that first freeze coming later, you get pollen lasting longer into the year and overall just a longer pollen season if you have less winter.

The general trend is that a warmer, milder winter means more pollen production because it lets the plants get started on their pollen season earlier, but different plants do prefer different conditions. Some plants really thrive in warm days and cool nights.

But it's not just temperature that controls pollen levels. For example, rain can wash all the pollen away for the short term, but more rain means more water for plants, which means more pollen in the long term.

Wind is another factor.

Imagine you've spread baking flour all over your kitchen. If the air is still and nothing's moving, the flour just kind of sits on all of the surfaces. But if you put a fan in there, suddenly all of that flour is in the air. The same thing happens with pollen.

Pollen settles or it stays in the trees where it was formed until the wind blows, and that's what puts it into the air, and that's what lets your body encounter it. Pollen count isn't talking about pollen that's on the ground, it's talking about the pollen in the air ready for your body to encounter it.

The simple fact is that our planet is warming and the production of pollen is increasing. A warmer planet means shorter, more mild winters, which extends the growing season, and it extends the season for plants to produce pollen, so we get longer and more intense pollen seasons.

Carbon dioxide also actually increases the production of pollen from ragweed. An atmosphere with more carbon dioxide is producing more pollen, which makes allergy season way worse, not just because it's longer, but because there's more pollen out there for you to encounter.

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