Portland pollen forecast — International Rose Test Garden neighborhood

Today (30 August) pollen in International Rose Test Garden, Portland is high; ragweed is high; grass is moderate; mugwort is low. Tomorrow (31 August 2026) levels are similar - ragweed remains high, grass increasing, mugwort increasing. Over the following five days grass, mugwort, and ragweed will decrease. Forecasts are calculated by Airmine using satellites to map local vegetation and determine pollen season onset.

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International Rose Test Garden is a pacific Northwest city with Douglas fir, bigleaf maple, and hazels. Hazel and alder bloom in February — one of the earliest spring pollen triggers in the US. Tree season runs through May; grass follows through July.

Today - 30 August

  • Alder (Alnus):

    None

    0/100

  • Birch (Betula):

    None

    0/100

  • Hazel (Corylus):

    None

    0/100

  • Cypress (Cupressaceae):

    None

    0/100

  • Grass (Poaceae):

    Moderate

    38/100

  • Willow (Salicaceae):

    None

    0/100

  • Mugwort (Artemisia):

    Low

    21/100

  • Ragweed (Ambrosia):

    High

    63/100

High pollen levels may trigger sneezing, itchy eyes, and congestion. Airmine's neighbourhood estimates use satellites to map local vegetation and a statistical prediction model, updated four times daily.

Tomorrow - 31 August

  • Alder (Alnus):

    None

    0/100

  • Birch (Betula):

    None

    0/100

  • Hazel (Corylus):

    None

    0/100

  • Cypress (Cupressaceae):

    None

    0/100

  • Grass (Poaceae):

    High

    55/100

  • Willow (Salicaceae):

    None

    0/100

  • Mugwort (Artemisia):

    Moderate

    37/100

  • Ragweed (Ambrosia):

    High

    70/100

Other Landmarks in Portland

Alberta Arts District Division Street Forest Park Hawthorne District International Rose Test Garden Ladd's Addition Lan Su Chinese Garden Mississippi Avenue Mount Tabor Park Multnomah Falls Oregon Museum of Science and Industry Overlook Park Pearl District Portland Art Museum Powell Butte Nature Park Sellwood Slabtown St. Johns Willamette Waterfront Woodstock

Frequently Asked Questions

Is pollen high in Portland right now?

On 30 August 2026, overall pollen levels in Portland are high. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels

Will pollen levels change in Portland tomorrow?

On 31 August 2026, pollen conditions in Portland will be different from today, with ambrosia at high levels and artemisia, grass increasing

Is pollen expected to decrease in Portland this week?

According to the five-day outlook, ambrosia, artemisia, and grass pollen levels are expected to gradually decrease, suggesting improving conditions later in the week.

Which pollen types are currently active in Portland?

On 30 August 2026, Ambrosia is the dominant pollen source in Portland. grass and artemisia are also present but at lower levels. cypress are not currently active.

When is pollen season in Portland?
Like the rest of Portland, International Rose Test Garden experiences a season that opens with alder and birch from February before maple extends the tree season through March and April. Grass pollen rises through May and June, and mugwort and nettle extend exposure into September. The damp, mild regional climate keeps pollen counts lower than in drier parts of the country, though spring rain events can trigger brief spikes, a pattern felt across this part of Portland.
How often is the Portland pollen forecast updated?

The Portland pollen forecast is updated four times daily. See the timestamp below for the most recent update.

Does pollen in Portland come from nearby or far away?

Studies show that most pollen exposure (often 70–90%) comes from nearby sources, such as local trees and vegetation. A good pollen forecast therefore depends on accurately representing local vegetation. Pollen can travel long distances, but this usually matters only early in the season or during specific wind events.

Are pollen levels in Portland based on measurements or forecasts?

Pollen data is often misunderstood. Most "pollen levels" are not real-time measurements, but forecasts.

Direct pollen measurements are typically delayed by 1-2 days because they require manual analysis. To show current conditions in Portland, modern forecasts combine recent measurements, weather data, and information about local vegetation.

This allows us to estimate pollen levels for today and the coming days, not just report the past.

Airmine’s atmospheric monitoring platform was developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team, using satellite and Earth observation technologies to improve emissions monitoring.

Want to see pollen forecasts for other cities in United States?

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Check pollen in other popular cities:

Melton Rio de Janeiro Copenhagen Athens Denpasar Rome Cape Town Barcelona London Los Angeles New York

Data provided by Airmine — Last update: 30 August 2026 at 14:32 CEST (Data is updated four times daily.)

This page provides the latest public pollen forecast for International Rose Test Garden, Portland.

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Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.

Some text on this page may be generated or summarised using artificial intelligence (AI). Wherever possible, AI-generated content is enriched with Airmine's proprietary data to improve its accuracy and relevance. However, AI-generated content may still contain errors, omissions, or inaccuracies.