Yreka pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Yreka is high; grass and ragweed are high; mugwort is moderate.
Pollen Tomorrow
Tomorrow (21 September 2026) ragweed remains high, grass declining, mugwort declining.
7-Day Trend
Over the next week grass, mugwort, and ragweed will decrease.
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Features and forecast availability vary by region.
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) | High | 53/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Moderate | 28/100 |
| Ragweed (Ambrosia) | High | 70/100 |
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 | 46/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 22/100 | |
| Ragweed (Ambrosia) | High | 65/100 |
Local Environmental Conditions
Yreka's setting on the Shasta Valley in the Klamath Mountains foothills supports ponderosa pine, oak woodland, and farmland grasses as the leading local vegetation, all factoring into the pollen count through the year. Local parks and open ground tend to see higher pollen counts than the denser urban core. As with most of the region, counts tend to build gradually rather than spike overnight.
Yreka sees its pollen season open with olive and acacia from January with eucalyptus taking the lead 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, a defining feature of the local season.
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Resource Hub
Pollen forecast neighborhoods 2 neighborhoods
Frequently Asked Questions About Pollen in California
Is pollen high in Yreka right now?
On 20 September 2026, overall pollen levels in Yreka are high. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Yreka tomorrow?
On 21 September 2026, pollen conditions in Yreka will be different from today, with ambrosia at high levels and artemisia, grass continuing to decline
Is pollen expected to decrease in Yreka 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 Yreka?
On 20 September 2026, Ambrosia is the dominant pollen source in Yreka. grass and artemisia are also present but at lower levels.
When is pollen season in Yreka?
How often is the Yreka pollen forecast updated?
The Yreka pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Yreka 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 Yreka 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 Yreka, 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).
