Yorba Linda pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Yorba Linda is high; ragweed is high; grass is moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) grass remains moderate, ragweed remains high, mugwort no longer expected.
7-Day Trend
Over the next week grass, mugwort, and ragweed will increase.
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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 | 43/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 9/100 |
| 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 | 27/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | High | 58/100 |
Local Environmental Conditions
Yorba Linda's Orange County foothill setting features olive, chaparral scrub oak, and Torrey pine as the main tree pollen sources, with exposure varying between the chaparral-covered Chino Hills and the more built-up residential and commercial corridors along Yorba Linda Boulevard. The Santa Ana River corridor provides locally significant green space, while the foothill-valley gradient creates distinct pollen exposure differences between the hillside and valley floor areas.
Yorba Linda's Orange County California setting produces a season opening in January with olive and orange before grass from surrounding Inland Empire land peaks through March and April. Mugwort extends exposure into September, while the inland setting means higher temperatures than in coastal Southern California cities and the Santa Ana winds can periodically transport pollen across the Puente Hills setting.
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Frequently Asked Questions About Pollen in California
Is pollen high in Yorba Linda right now?
On 20 September 2026, overall pollen levels in Yorba Linda are high. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Yorba Linda tomorrow?
On 21 September 2026, pollen conditions in Yorba Linda will be different from today, with ambrosia at high levels, grass at moderate levels
Is pollen expected to decrease in Yorba Linda this week?
According to the five-day outlook, ambrosia, artemisia, and grass pollen levels will increase later in the week.
Which pollen types are currently active in Yorba Linda?
On 20 September 2026, Ambrosia is the dominant pollen source in Yorba Linda. grass and artemisia are also present but at lower levels.
When is pollen season in Yorba Linda?
How often is the Yorba Linda pollen forecast updated?
The Yorba Linda pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Yorba Linda 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 Yorba Linda 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 Yorba Linda, 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).
