Fall may not bring quick relief from allergies this year, as weed pollen could stay high across much of the US and grass pollen may linger in parts of the East and Midwest.
- Weed pollen could remain a major fall allergy trigger across the US
- Grass pollen may stay high in parts of the East and Midwest
- Climate and weather changes can extend pollen seasons and increase exposure
Fall may not bring relief for people with seasonal allergies this year. AccuWeather’s 2026 forecast warns that weed pollen could remain a widespread problem across the US, while grass pollen may stay high in parts of the East and Midwest (1✔ ✔Trusted Source
Fall allergy forecast: Weed, grass pollen to surge in parts of US
).
Warm temperatures, rainfall, and moisture are creating conditions that can support continued pollen production and prolong allergy exposure.
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What does the AccuWeather fall allergy forecast predict for 2026?
According to the forecast, weed pollen is expected to be the bigger concern across much of the United States this fall, while grass pollen could remain elevated in parts of the East and Midwest.
Warm and wet weather is helping pollen levels climb, particularly across the eastern half of the country.
The forecast is especially relevant during the transition from late summer into autumn, when grass and weed pollen become important triggers of seasonal allergic rhinitis.
Tree pollen commonly dominates earlier in the year, while grass pollen causes symptoms in late spring and early summer, and weed pollen becomes more important during late summer and fall (2✔ ✔Trusted Source
Outdoor Allergens
For people who already experience hay fever, the increase can mean more sneezing, a runny or blocked nose, itchy eyes, and throat irritation.
Seasonal allergic rhinitis occurs when the immune system overreacts to airborne allergens such as pollen and produces an allergic response.
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What Symptoms Can High Pollen Levels Cause?
Seasonal allergic rhinitis, commonly called hay fever, can cause:
- Sneezing
- Runny or blocked nose
- Itchy nose and throat
- Watery or itchy eyes
- Nasal congestion
- Irritation around the eyes, nose, or throat
Pollen and mold spores can trigger an immune response in susceptible people. The body recognizes the allergen and produces Immunoglobulin E, or IgE, antibodies that contribute to the release of chemicals responsible for allergy symptoms.
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Which US regions could see the highest grass pollen?
AccuWeather expects grass pollen to remain elevated in parts of the East, while conditions in the West and Southeast could keep levels lower in some areas.
The table below highlights how grass, weed, ragweed, and mold pollen are expected to behave across different parts of the US this fall.
|
Pollen Type |
What To Expect This Fall |
Key US Areas |
|
Grass pollen |
Could remain high through late summer and early fall |
East, Mid-Atlantic and Midwest, including New York City, Philadelphia, Detroit and Chicago |
|
Weed pollen |
Could remain widespread and linger into October |
Southeast and southern Rockies |
|
Ragweed |
Remains a major fall allergy trigger |
Broad areas across North America |
|
Mold spores |
Levels will vary with local weather and moisture |
Several US regions |
Drier conditions in much of the West may limit grass growth, while dry periods in parts of the Southeast could also keep grass pollen lower in some locations.
How Is Climate Change Making Pollen Seasons Longer?
Climate change can make pollen seasons start earlier, last longer, and produce more pollen.
According to the CDC, warmer temperatures, changing rainfall patterns, more frost-free days and rising carbon dioxide levels can affect pollen production and increase the number of days people are exposed to it (3✔ ✔Trusted Source
Pollen and Your Health
Pollen seasons are about 20 days longer than in 1990, with around 21% more pollen. Experiments with doubled CO₂ also found 61% more ragweed pollen (4✔ ✔Trusted Source
Why Allergies Are Getting Worse, From Pollen to Pollution
These changes are especially important for fall allergies because ragweed is a major pollen source and a single plant can produce about 1 billion pollen grains in one season.
- Warmer temperatures: Can trigger earlier pollen production and extend the season.
- Changing rainfall: Can influence plant growth and pollen release.
- More frost-free days: Give pollen-producing plants a longer growing period.
- Higher CO₂: May increase plant growth and pollen production.
How Much Pollen Are Americans Being Exposed To?
A recent pollen study helps put this year’s allergy forecast into a bigger picture. Researchers combined pollen measurements collected across the US over 22 years, making it easier to see how pollen seasons vary by location and how weather conditions can influence exposure (5✔ ✔Trusted Source
Pollen Season Timing and Concentrations in the United States: Developing a Standardized Pollen Dataset Using Data from the National Allergy Bureau (NAB) (2003–2024)
).
What Did the Researchers Actually Look At?
|
Finding |
What It Tells Us About Allergies |
|
22 years of data |
Researchers could examine pollen patterns over a long period rather than relying on one allergy season. |
|
125 monitoring stations |
The study captured pollen conditions across many different parts of the US. |
|
42 states covered |
The findings provide a broad picture of pollen exposure across the country. |
|
1.175 million+ pollen observations |
Researchers had a large amount of data to examine when pollen seasons started, peaked and declined. |
|
15%–30% of the US population |
This is the estimated proportion of people affected by allergic rhinitis, showing why changes in pollen exposure matter for public health. |
The connection to this fall’s forecast is important: pollen does not behave the same way everywhere. Temperature, rainfall, and growing conditions can change when plants release pollen and how long exposure lasts.
This helps explain why some US regions may continue seeing high grass or weed pollen even as fall begins.
The researchers say the standardized dataset could also help improve pollen forecasting, allergy warnings, and understanding of asthma-related risks during peak pollen periods.
How Can You Reduce Pollen Exposure This Fall?
People with pollen allergies can reduce exposure by taking a few simple precautions, especially when pollen levels are high:
- Check pollen forecasts: Limit outdoor time when pollen levels are high.
- Keep windows closed: Use air conditioning or an indoor air purifier when possible.
- Shower after being outdoors: Wash pollen from your skin and hair.
- Change clothes: Change after spending time outdoors to avoid bringing pollen indoors.
- Keep shoes outside: Remove shoes before entering the home to reduce tracked-in pollen.
- Keep car windows closed: This can help limit pollen exposure while traveling.
- Avoid mowing or raking: These activities can stir up pollen and mold.
- Take prescribed medicines: Follow your healthcare provider’s advice for allergy or asthma medicines.
Frequently Asked Questions
Q: Will pollen levels stay high in the US this fall?
A: According to the supplied AccuWeather forecast, weed pollen could remain a widespread concern, while grass pollen may stay elevated in parts of the East and Midwest.
Q: Which pollen is expected to be the biggest fall concern?
A: Weed pollen is expected to be the larger concern across much of the US, with levels potentially remaining high into October in some areas.
Q: Which areas could see high grass pollen?
A: The East, Mid-Atlantic, and Midwest could see elevated grass pollen. AccuWeather highlighted areas around New York City, Philadelphia, Detroit, and Chicago.
Q: Where could weed pollen be highest?
A: The forecast highlights parts of the Southeast and southern Rockies, including areas around Raleigh, Nashville, Atlanta, Little Rock, Denver, Salt Lake City and Albuquerque.
Q: Why can pollen remain high after rain?
A: Rain can temporarily wash pollen out of the air, but rainfall also provides moisture that can help plants grow. Once conditions become favorable again, pollen levels can rise.
Q: Can climate change make pollen seasons longer?
A: Yes. According to the CDC information included in the report, warmer temperatures, changing rainfall, longer growing seasons and higher carbon dioxide levels can affect when pollen seasons start and end and how much pollen plants produce.
Q: What symptoms can high pollen cause?
A: Common symptoms include sneezing, a runny or blocked nose, an itchy nose and throat, watery eyes, and nasal congestion. People with asthma may also experience worsening respiratory symptoms.
References:
- Fall allergy forecast: Weed, grass pollen to surge in parts of US – (https://www.accuweather.com/en/weather-forecasts/fall-allergy-forecast-weed-grass-pollen-to-surge-in-parts-of-us/1923626)
- Outdoor Allergens – (https://www.aaaai.org/tools-for-the-public/conditions-library/allergies/outdoor-allergens-ttr)
- Pollen and Your Health – (https://www.cdc.gov/climate-health/php/effects/pollen-health.html)
- Why Allergies Are Getting Worse, From Pollen to Pollution – (https://scienceinsights.org/why-allergies-are-getting-worse-from-pollen-to-pollution/)
- Pollen Season Timing and Concentrations in the United States: Developing a Standardized Pollen Dataset Using Data from the National Allergy Bureau (NAB) (2003–2024) – (https://www.mdpi.com/2073-4433/17/7/635)
Source-Medindia