Mission Hills HS's Baseball Diamond, San Marcos, California Pollen Forecast - Today, Tomorrow and the Week Ahead
Pollen Today
Today (10 October) pollen in Mission Hills HS's Baseball Diamond, San Marcos, California is moderate; ragweed is moderate; grass, mold (alternaria), and mold (cladosporium) are low.
Pollen Tomorrow
Tomorrow (11 October 2026) mold (alternaria) remains low, mold (cladosporium) remains low, ragweed declining, grass no longer expected.
7-Day Trend
Over the next week grass, mugwort, ragweed, mold (alternaria), and mold (cladosporium) will increase.
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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 | 3/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Moderate | 30/100 |
| Mold (Alternaria) | Low | 18/100 |
| Mold (Cladosporium) | Low | 24/100 |
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) | Low | 20/100 | |
| Mold (Alternaria) | Low | 12/100 | |
| Mold (Cladosporium) | Low | 23/100 |
Local Environmental Conditions
The area around this part of San Marcos is a mix of woodland and scrubland. Among allergenic trees nearby, oak leads, followed by plane tree and willow. Grasses also feature strongly, alongside mugwort and pigweed among the weeds. In the immediate area, scrubland contributes pollen from shrubs, grasses and herbs.
Oak, plane tree and willow lead the season in mid-spring, as temperatures climb to around 15°C, and tree pollen reaches its peak. Grasses take over in late spring and keep pollen in the air into early fall. The season closes with mugwort and pigweed through summer. Spring is the wettest time of year, and heavy showers can bring short breaks in pollen.
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Pollen forecast neighborhoods 1 neighborhood
Sports venues in San Marcos, California 2 sports venues
Frequently Asked Questions About Pollen in California
Is pollen high in San Marcos, California right now?
On 10 October 2026, overall pollen levels in San Marcos, California are moderate. Ambrosia is the main contributor to airborne pollen, while grass remain at lower levels
Will pollen levels change in San Marcos, California tomorrow?
On 11 October 2026, pollen conditions in San Marcos, California will be different from today, with ambrosia continuing to decline
Is pollen expected to decrease in San Marcos, California 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 San Marcos, California?
On 10 October 2026, Ambrosia is the dominant pollen source in San Marcos, California. grass are also present but at lower levels. artemisia are not currently active.
When is pollen season in San Marcos, California?
How often is the San Marcos, California pollen forecast updated?
The San Marcos, California pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in San Marcos, California 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 San Marcos, California 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 San Marcos, California, 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).
