Pollen CountPollen from trees, grasses, and weeds can be inhaled and cause allergy and asthma symptoms. Pollen allergies are often seasonal, and allergy and asthma symptoms occur when the amount of pollen in the air is high.

Get tips from our experts on navigating life with allergies.

If you don't live in Denver, search for the pollen count in your area at the American Academy of Allergy Asthma and Immunology (AAAAI) website.


Denver-area Current Pollen Count (Last Updated: 10/12/2021)

If you don't live in Denver, search for the pollen count in your area
at the American Academy of Allergy, Asthma and Immunology(AAAAI) website.

Generally, the pollen season can be subdivided into three distinct seasons, each of which can affect different people. Early spring is when trees pollinate. Grasses pollinate during the summer, and weeds pollinate late summer into the fall. In Colorado, trees generally begin pollinating in February and continue through June. Grass pollen season runs from early May through August, and weed pollen is in the air from July through September.

Pollen counts can vary widely from day to day depending on weather conditions. Generally, pollen levels increase on warm, sunny days. Windy days also commonly have higher pollen levels. Rain washes pollen out of the air, reducing pollen counts. Cool, damp weather also tends to keep pollen levels low.

Pollen GrainsNational Jewish Health monitors pollen levels at its main health campus in Denver, Colorado. On weekday mornings, a technician retrieves a slide from a Burkard pollen and spore sampler. The slide is covered with a sticky substance to which pollen grains have adhered during the previous 24 hours. The technician then stains the slide, puts it under a microscope, and identifies and counts pollen grains to determine what kind and how much pollen is in the air.

The resulting pollen count is then distributed to various National Jewish Health physicians, the National Jewish Health clinical research unit, the local media, and it is also posted here on the website.

The pollen counts help inform physicians’ discussions with their patients about allergies and symptoms. They are used by clinical researchers at National Jewish Health who are evaluating potential allergy medications. The pollen counts are also tracked year over year to identify and compare trends.

NOTE: Our pollen collection process is heavily dependent on having good weather conditions for gathering the sample and at times, we are unable to provide accurate data. In these cases, please refer to the seasonal year-over-year data we provide, as it is generally a good indicator of current conditions.

Outsmart Spring Allergies

Learn about spring allergies and global warming. Get info on what you can do to minimize your allergy symptoms from the most common spring allergens.

Surviving Spring Allergies

Learn to manage your spring allergy symptoms with our helpful tips in our Surviving Spring Allergies infographic.


Navigating Life With Allergies

While spring is in bloom, not everyone is excited about it. For those who have allergies, it can be a difficult time as the body tries to adjust to all that's floating in the air and growing from the ground up. You can trust us and our allergy experts to help you cope with allergy symptoms and find relief.

Allergy Tips

A large part of dealing with allergies is being proactive to treat your symptoms before they even begin. Clues for treating allergy symptoms:


Nasal Wash Treatment

Many people with asthma or other lung problems also have nasal and sinus symptoms. Drainage from your nose and sinuses can make asthma worse, especially at night. A salt water nasal wash, or nasal irrigation, can help reduce this.


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