The allergy season arrived early and is hitting hard across much of the country, with medium-to-high pollen levels expected into the weekend.

The top 5 cities with the highest pollen forecasts are Grand Rapids, Muskegon, Flint, South Bend, and Lansing.

That’s according to IQVIA, a healthcare analytics company that operates www.pollen.com.

They use historical data and daily pollen counts to make these predictions, considering local factors like weather.

They say tree pollen is the main culprit, affecting allergy sufferers from February to May, overlapping with grass pollen in late spring.