How are the pollen counts determined?
The counts are performed under a microscope from pollen samples collected by an air sampler on the roof of our office in Greenfield. Unlike some pollen websites, we do not use historical or predicted data in our daily counts ‐ they are actual observations made by one of our staff. Pollen is sampled during the 24 hours before counting, so sudden changes in weather such as rain or wind may produce changes in pollen levels not yet shown in the count.
Historical Pollen and Mold Averages
Our historical averages are calculated from multi‐day rolling averages using pollen data collected from 1995 to 2024 and mold data collected from 2004 to 2022. Due to variations in weather and count availability, we have found that the rolling average method produces much more meaningful average counts than the calendar of single‐day historical averages that we used to provide. For full season graphs and comparison of past seasons, visit the Pollen Explorer.
