San Benito County Historical Society, Hollister Pollen Forecast - Today, Tomorrow and the Week Ahead
Pollen Today
Today (11 October) pollen in San Benito County Historical Society, Hollister is moderate; ragweed is moderate; mold (alternaria) and mold (cladosporium) are low.
Pollen Tomorrow
Tomorrow (12 October 2026) levels are similar to today.
7-Day Trend
Over the next week grass, mugwort, ragweed, mold (alternaria), and mold (cladosporium) will increase.
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Pollen Risk
Today - 11 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) | None | 0/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Moderate | 29/100 |
| Mold (Alternaria) | Low | 8/100 |
| Mold (Cladosporium) | Low | 18/100 |
Tomorrow - 12 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 | 27/100 | |
| Mold (Alternaria) | Low | 7/100 | |
| Mold (Cladosporium) | Low | 16/100 |
Local Environmental Conditions
This site in Hollister is surrounded mainly by built-up land, which covers around 80% of the nearby area. A nearby park adds mown lawns and planted trees to the local pollen mix. Locally, street trees, gardens and lawns supply most pollen in the built-up parts. Roadside verges and patches of open ground provide further room for grasses and weeds.
Then come the grasses, strongest in midsummer and fading by early fall. Rain is heaviest in winter, often giving short breaks from high pollen levels. Actual levels on any given day depend on the weather, with dry, breezy days the worst and wet days the mildest. Between late fall and the first tree flowering, pollen levels stay low, with midwinter usually the quietest time.
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Frequently Asked Questions About Pollen in California
Is pollen high in Hollister right now?
On 11 October 2026, overall pollen levels in Hollister are moderate. Ambrosia is the main contributor to airborne pollen
Will pollen levels change in Hollister tomorrow?
On 12 October 2026, pollen conditions in Hollister will be similar to today, with ambrosia at moderate levels
Is pollen expected to decrease in Hollister this week?
According to the five-day outlook, artemisia, grass, and ambrosia pollen levels will increase later in the week.
Which pollen types are currently active in Hollister?
On 11 October 2026, Ambrosia is the dominant pollen source in Hollister. artemisia and grass are not currently active.
When is pollen season in Hollister?
How often is the Hollister pollen forecast updated?
The Hollister pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Hollister 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 Hollister 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 Hollister, 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. |
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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).
