What Is Pollen Count, And How Does It Change? | ZYRTEC®

What Is Pollen Count?

Pollen count is a measure of the average number of pollen grains per cubic meter2. It’s usually recorded during the day, so pollen count forecasts are likely to reflect daytime figures too.

Pollen grains are often measured using the rotorod technique. This uses greased silicone rods to collect particles from the air, often over 24 hours3.Some devices are capable of measuring pollen counts over a period of several days4.

Pollen counts of 50 or less are considered low, while 1,000 or more is very high5. These measures can differ slightly according to pollen type.

If you suffer from seasonal allergies, sometimes referred to as hay fever, pollen count can make a big difference to how severe they are.

View our guide to pollen by season to better understand how the passing months may impact your symptoms.

What Time Of Day Is The Pollen Count The Highest and Lowest?

The amount of pollen in the air varies from day to day, as well as throughout the day. Planning your outdoor activities for times when the pollen count usually drops may help minimize hay fever symptoms.

When Is The Pollen Count High?

Pollen counts usually rise in the morning, and reach their peak by midday or early afternoon. This is the time of day that allergies are often the worst, since there is a high concentration of pollen in the air.

The release of pollen also depends on the species of plant or tree – so if you’re allergic to a certain type of pollen, you may notice symptoms peak at different times.

If the worst time of day for your allergies changes, you might want to speak to your doctor in case a different type of pollen or another allergen is the source.

When Is The Pollen Count Low?

On an average day, pollen counts rise during the morning, peak about midday, and then gradually fall. So the lowest pollen counts are usually before dawn and in the late afternoon to early evening. But this is all relative – if the pollen count is very high, a moderate decrease later in the day may still leave a high concentration of pollen in the air.

Pollen levels are lower overall at nights, but in certain conditions the effects of pollen can feel more intense – when this is the case, your sleep might be affected6. Cooler night-time conditions can also cause pollen to descend to ground or second-story level7.

Knowing the most likely times for a low pollen count ensures you can better plan your days during hay fever season.

Pollen Count Factors