Broomfield pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Broomfield is moderate; ragweed is moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) mugwort remains low, ragweed increasing, grass at low levels.
7-Day Trend
Over the next week grass will increase; mugwort and ragweed will decrease.
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Pollen Risk
Today - 20 September
| Pollen species | Level | Value |
|---|---|---|
| Alder (Alnus) | None | 0/100 |
| Birch (Betula) | None | 0/100 |
| Hazel (Corylus) | None | 0/100 |
| Cypress (Cupressaceae) | None | 0/100 |
| Grass (Poaceae) | None | 0/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 3/100 |
| Ragweed (Ambrosia) | Moderate | 47/100 |
Tomorrow - 21 September
| Pollen species | Level | Value | 7-Day Trend |
|---|---|---|---|
| Alder (Alnus) | None | 0/100 | — |
| Birch (Betula) | None | 0/100 | — |
| Hazel (Corylus) | None | 0/100 | — |
| Cypress (Cupressaceae) | None | 0/100 | — |
| Grass (Poaceae) | Low | 2/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 11/100 | |
| Ragweed (Ambrosia) | High | 54/100 |
Local Environmental Conditions
Broomfield's Front Range Colorado suburban setting features cottonwood, elm, and oak as the main tree pollen sources, with exposure varying between the greener residential areas around the numerous open space preserves and the more built-up commercial corridors. The Front Range Open Space corridor and the Rocky Mountain backdrop create distinct topographic effects, while the transition from foothill to plains vegetation creates varied local pollen zones.
Broomfield's Front Range Colorado suburban setting produces a season opening with elm and cottonwood in March before grass from surrounding Colorado plains peaks through May and June. Mugwort extends exposure into September, while the elevated Front Range position means the season begins later than in lower elevation cities and the Rocky Mountain foothills concentrate pollen under certain wind conditions.
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Frequently Asked Questions About Pollen in Colorado
Is pollen high in Broomfield right now?
On 20 September 2026, overall pollen levels in Broomfield are moderate. Ambrosia is the main contributor to airborne pollen, while artemisia remain at lower levels
Will pollen levels change in Broomfield tomorrow?
On 21 September 2026, pollen conditions in Broomfield will be different from today, with artemisia at low levels, grass at low levels and ambrosia increasing
Is pollen expected to decrease in Broomfield this week?
According to the five-day outlook, ambrosia and artemisia pollen levels are expected to gradually decrease, while grass pollen will increase, suggesting mixed conditions later in the week.
Which pollen types are currently active in Broomfield?
On 20 September 2026, Ambrosia is the dominant pollen source in Broomfield. artemisia are also present but at lower levels. grass are not currently active.
When is pollen season in Broomfield?
How often is the Broomfield pollen forecast updated?
The Broomfield pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Broomfield 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 Broomfield 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 Broomfield, 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.
Understanding the Scale
The 0–100 scores represent risk levels, not direct measurements of pollen or air pollutant concentrations. Higher scores indicate higher risk. Pollen and air quality use different thresholds.
Pollen
| None | 0 | No or negligible risk of exposure. Pollen/mold exposure is expected to be minimal. |
| Low | 0-25 | Low risk of exposure. Small amounts of pollen or mold spores may be present. |
| Moderate | 25-50 | Moderate risk of exposure. Pollen/mold exposure is expected to be noticeable. |
| High | 50-75 | High risk of exposure. Elevated pollen/mold exposure is expected. |
| Very High | 75-100 | Very high risk of exposure. Pollen/mold exposure is expected to be at or near its highest levels. |
Get More in the Airmine Pollen app
Get 15-day pollen forecasts with morning, afternoon and evening detail, plus 5-day air quality forecasts. Explore interactive pollen risk maps, estimated pollen season start, route profiles and a symptoms diary.
Features and forecast availability vary by region. Currently covering Europe, the contiguous US, southern Canada, South Africa, Australia, Indonesia (Java & Bali), Brazil, Paraguay, Uruguay and the Buenos Aires area.
Developed with support from the European Space Agency (ESA) Business Applications and Space Solutions (BASS).
