Mount Shasta pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Mount Shasta is high; ragweed is high; grass is moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) levels are similar to today.
7-Day Trend
Over the next week grass, 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) | Moderate | 33/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 20/100 |
| Ragweed (Ambrosia) | High | 64/100 |
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) | Moderate | 29/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 17/100 | |
| Ragweed (Ambrosia) | High | 61/100 |
Local Environmental Conditions
Set on a mountain town at the base of the Mount Shasta volcano in far northern California, Mount Shasta's landscape is defined by mixed conifer forest alongside spring-fed meadow grasses and cedar and fir stands, the main contributors to seasonal pollen exposure. Local parks and open ground tend to see higher pollen counts than the denser urban core. Microclimates within the area can shift the timing slightly from one neighborhood to the next.
In Mount Shasta, pollen season begins with olive and acacia starting in January with eucalyptus following close behind through February. Grass follows, peaking through March and April, while light weed pollen carries into September. Onshore Pacific breezes periodically clear the air, though inland valleys can still see elevated counts.
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Resource Hub
Pollen forecast neighborhoods 6 neighborhoods
Frequently Asked Questions About Pollen in California
Is pollen high in Mount Shasta right now?
On 20 September 2026, overall pollen levels in Mount Shasta are high. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Mount Shasta tomorrow?
On 21 September 2026, pollen conditions in Mount Shasta will be similar to today, with ambrosia at high levels, artemisia at low levels, grass at moderate levels
Is pollen expected to decrease in Mount Shasta 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 Mount Shasta?
On 20 September 2026, Ambrosia is the dominant pollen source in Mount Shasta. grass and artemisia are also present but at lower levels.
When is pollen season in Mount Shasta?
How often is the Mount Shasta pollen forecast updated?
The Mount Shasta pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Mount Shasta 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 Mount Shasta 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 Mount Shasta, 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).
