Grass Valley Pollen Forecast - Today, Tomorrow and the Week Ahead
Pollen Today
Today (10 October) pollen in Grass Valley is moderate; ragweed and mold (cladosporium) are moderate; grass and mold (alternaria) are low.
Pollen Tomorrow
Tomorrow (11 October 2026) ragweed remains moderate, mold (alternaria) remains low, mold (cladosporium) remains moderate, grass no longer expected.
7-Day Trend
Over the next week grass, mugwort, ragweed, and mold (alternaria) will increase; mold (cladosporium) will decrease.
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Pollen Risk
Today - 10 October
| 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) | Low | 1/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Moderate | 27/100 |
| Mold (Alternaria) | Low | 14/100 |
| Mold (Cladosporium) | Moderate | 35/100 |
Tomorrow - 11 October
| 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) | None | 0/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | Moderate | 26/100 | |
| Mold (Alternaria) | Low | 13/100 | |
| Mold (Cladosporium) | Moderate | 32/100 |
Local Environmental Conditions
The center of Grass Valley is surrounded mainly by woodland, which covers around 55% of the nearby area, with a good deal of built-up land. Oak heads the list of allergenic trees nearby, ahead of maple. Grass pollen is plentiful, while plantain and mugwort lead among the weeds. Compared with most places, oak is especially widespread here, which makes it one of the key local allergens.
Tree pollen then builds as oak flowers, peaking around mid-spring. Grasses take over, peaking around late spring and fading by midsummer. Plantain keeps pollen in the air from mid-spring into midsummer. Levels are typically at their highest around mid-spring, when oak is in full flower. Locally, temperatures range from around 10°C in the coldest month to around 30°C in the warmest.
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Frequently Asked Questions About Pollen in California
Is pollen high in Grass Valley right now?
On 10 October 2026, overall pollen levels in Grass Valley are moderate. Ambrosia is the main contributor to airborne pollen, while grass remain at lower levels
Will pollen levels change in Grass Valley tomorrow?
On 11 October 2026, pollen conditions in Grass Valley will be different from today, with ambrosia at moderate levels
Is pollen expected to decrease in Grass Valley this week?
According to the five-day outlook, grass, ambrosia, and artemisia pollen levels will increase later in the week.
Which pollen types are currently active in Grass Valley?
On 10 October 2026, Ambrosia is the dominant pollen source in Grass Valley. grass are also present but at lower levels. artemisia are not currently active.
When is pollen season in Grass Valley?
How often is the Grass Valley pollen forecast updated?
The Grass Valley pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Grass Valley 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 Grass Valley 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 Grass Valley, 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 pollen scores represent risk levels, not direct pollen measurements. Higher scores indicate higher risk.
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).
