- Allergy symptoms are usually the strongest in March and April (because of tree pollen), June (grass pollen), and September (weed pollen). Pollen season often ends by late November, but the weather can make it last longer or end sooner.
- To manage allergies, use HEPA filters, check pollen counts, and avoid being outside during high pollen times. Be sure to shower after being outdoors and clean your home often to reduce allergens.
- Before allergy season starts, take medicines like antihistamines or nasal sprays. This helps your body get ready and reduces allergy symptoms later on.
Oregon offers breathtaking scenery, lush greenery, and plenty of outdoor adventures. But for many residents, it also brings the challenge of year-round allergies. Oregon’s mild weather and many plants mean pollen is in the air almost all year. In spring, cedar and birch trees release pollen. In summer, it’s ryegrass, and in fall, ragweed takes over. No matter the season, something is always causing allergies.
Here's what you need to know about Oregon’s allergy seasons so you can prepare and manage your symptoms.
When is Pollen Season in Oregon?
Pollen season in Oregon lasts all year, which makes it tough for allergy sufferers to catch a break. It begins in spring with tree pollen, as trees like alder, birch, cedar, and oak release large amounts into the air. In late spring and early summer, grass pollen like ryegrass and bentgrass becomes a big problem. By late summer and early fall, weeds like ragweed and sagebrush cause most allergies. Since there’s little break between pollen seasons, dealing with allergies in Oregon can be tough all year.
What are the Worst Months for Allergies in Oregon?
The worst months for allergies in Oregon are March, April, June, and September. Here’s why:
- March and April: Tree pollen is at its peak. Trees like alder, birch, and oak release lots of pollen into the air, which can trigger sneezing, itchy eyes, and other allergy symptoms [*].
- June: This is often the hardest month for allergy sufferers because grass pollen, especially from ryegrass and bentgrass, is at its highest. Grass pollen can travel far in the air, making it hard to avoid [*].
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September: Weeds like ragweed and sagebrush release their pollen during this time. Weed pollen can be especially tough because it’s small and spreads easily.
When Does Pollen Season End in Oregon?
Allergy sufferers in Oregon often find relief as pollen season comes to an end around late November. However, the timing can change depending on the weather. Warmer weather and longer growing seasons can make pollen last longer. Meanwhile, an early frost or heavy rain can end the season sooner. While the season typically finishes in late November, weather conditions can shift the timing.
Common Allergens in Oregon
Common allergens in Oregon include pollen from trees, grasses, and weeds. These can vary throughout the year as well as dust mites, pet dander, and mold.
Tree pollen in early spring includes:
- Alder
- Birch
- Cedar
- Oak
- Pine
Grass pollen in late spring to early summer includes:
- Ryegrass
- Bentgrass
- Timothy grass
- Fescue
Weed pollen in late summer to early fall includes:
- Ragweed
- Sagebrush
- Chenopods
Russian thistle
Other common year-round allergens include:
How to Prepare for Seasonal Allergies in Oregon
Seasonal allergies in Oregon can be tough, but with the right steps, you can reduce your symptoms and enjoy the outdoors more comfortably. Here are some simple tips to help you get ready and manage your allergies:
- Check pollen counts: Keep track of daily pollen forecasts to help you plan outdoor activities accordingly.
- Stay indoors during peak pollen times: Pollen levels are usually highest in the morning, after the dew dries, and into the early afternoon. Sometimes, they stay high until late afternoon. Limit your outdoor exposure during these times to reduce symptoms.
- Keep windows closed: Keep windows shut in your home and car, especially during high pollen times to prevent pollen from entering and settling indoors.
- Use HEPA filters: Use HEPA filters in your air purifiers and heating or cooling systems to catch tiny allergens like pollen, dust mites, and pet dander. These filters help clean the air in your home, so it is easier to breathe during allergy season.
- Take your allergy medications: Take allergy medicines like antihistamines or other treatments to help with sneezing and itchy eyes. For the best results, start using them before allergy season begins. A combination nasal spray, like Allermi, is a great option. Its active ingredients work together to relieve your allergies while reducing side effects.
- Clean regularly: Vacuum with a HEPA-filter vacuum, dust frequently, and wash bedding often to remove allergens that may accumulate in your home.
- Wear a pollen mask: If you need to be outside during peak pollen times, wear a pollen mask. This mask helps you breathe easier when you’re outdoors, especially during high-pollen seasons. It filters out allergens and reduces your exposure.
- Shower and change clothes: After spending time outdoors, take a shower and change your clothes to remove any pollen that may have clung to you. This prevents allergens from spreading indoors.
The Bottom Line
Stay informed about pollen seasons, use HEPA filters, and take proactive measures. These are all essential steps to reduce symptoms. Don’t forget to use a combination nasal spray, such as Allermi, for comprehensive relief with fewer side effects.
Talk to your doctor before using any new allergy medicines to make sure they are safe and right for you. Your doctor can help you find the best way to feel better and stay healthy.
References:
- Asam, C., Hofer, H., Wolf, M., Aglas, L., & Wallner, M. (2015). Tree pollen allergens—An update from a molecular perspective. Allergy, 70(10), 1201. https://doi.org/10.1111/all.12696
- Pollen allergies. (2025, January 7). Asthma & Allergy Foundation of America. https://aafa.org/allergies/types-of-allergies/pollen-allergy/
