Ukiah pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Ukiah is high; ragweed is high; grass is moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) ragweed remains high, grass increasing, mugwort increasing.
7-Day Trend
Over the next week ragweed will increase; grass and mugwort 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 | 41/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 24/100 |
| Ragweed (Ambrosia) | High | 58/100 |
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) | High | 55/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Moderate | 38/100 | |
| Ragweed (Ambrosia) | High | 70/100 |
Local Environmental Conditions
Set on the Russian River valley in Mendocino County wine country, Ukiah's landscape is defined by vineyard rows alongside coast live oak and Douglas fir on the hillsides, the main contributors to seasonal pollen exposure. None of this is unusual for a town with Ukiah's particular mix of terrain and plant life. None of this differs sharply from one year to the next barring unusual weather.
Pollen season in Ukiah starts with olive and acacia in January before eucalyptus extends the tree season through February. A grass pollen peak follows through March and April; sagebrush and mugwort extend exposure into early autumn. 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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Frequently Asked Questions About Pollen in California
Is pollen high in Ukiah right now?
On 20 September 2026, overall pollen levels in Ukiah are high. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Ukiah tomorrow?
On 21 September 2026, pollen conditions in Ukiah will be different from today, with ambrosia at high levels and artemisia, grass increasing
Is pollen expected to decrease in Ukiah this week?
According to the five-day outlook, artemisia and grass pollen levels are expected to gradually decrease, while ambrosia pollen will increase, suggesting mixed conditions later in the week.
Which pollen types are currently active in Ukiah?
On 20 September 2026, Ambrosia is the dominant pollen source in Ukiah. grass and artemisia are also present but at lower levels.
When is pollen season in Ukiah?
How often is the Ukiah pollen forecast updated?
The Ukiah pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Ukiah 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 Ukiah 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 Ukiah, 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).
