Pollen levels can go from zero to ten thousand pollen grains per cubic meter and back to zero, all within one day. This fact makes hourly pollen counts very important to managing seasonal allergies. Ideally, you would do all of your outdoor activities when pollen levels are low and stay inside when pollen levels are high. Why does pollen fluctuate so much throughout the day?
Plants benefit when they spread their pollen efficiently. Because of this, many plants have developed flowers that are highly effective at spreading pollen in the wind. Often the windiest part of the day is also the time of day with the highest pollen count. Conversely, extended periods of calm air lead to low pollen levels. In many areas, even in peak pollen season, the pollen count will drop to zero right before sunrise because the air has stopped moving and the pollen has settled to the ground.
Rain can wash pollen out of the air and provide a temporary relief and fall frosts can also kill the weeds that disperse pollen and can end certain pollen seasons. There are many other meteorological and biological factors involved in pollen release and dispersion that are difficult to summarize. Take comfort in knowing that Pollen Wise can give you up to date pollen counts around the clock.