San Juan Capistrano Pollen Forecast - Today, Tomorrow and the Week Ahead
Pollen Today
Today (11 October) pollen in San Juan Capistrano is moderate; ragweed is moderate; grass, mold (alternaria), and mold (cladosporium) are low.
Pollen Tomorrow
Tomorrow (12 October 2026) ragweed remains moderate, mold (alternaria) remains low, mold (cladosporium) remains low, 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 - 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) | Low | 6/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Moderate | 44/100 |
| Mold (Alternaria) | Low | 13/100 |
| Mold (Cladosporium) | Low | 17/100 |
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 | 33/100 | |
| Mold (Alternaria) | Low | 8/100 | |
| Mold (Cladosporium) | Low | 15/100 |
Local Environmental Conditions
Most of the area around this site in San Juan Capistrano is built-up land, with some woodland and open grassland. Grass pollen is significant here, and pigweed and mugwort contribute weed pollen. Around here, planted trees and mown lawns are the main sources in the built-up parts. Grasses along roadsides, verges and open ground also add to the overall pollen load.
Tree pollen comes first, peaking in early spring. Grasses take over in late spring and keep pollen in the air into mid-fall. Later, pigweed and mugwort keep weed pollen in the air from early summer into early fall. Spring is the wettest time of year, and heavy showers can bring short breaks in pollen.
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Frequently Asked Questions About Pollen in California
Is pollen high in San Juan Capistrano right now?
On 11 October 2026, overall pollen levels in San Juan Capistrano are moderate. Ambrosia is the main contributor to airborne pollen, while grass remain at lower levels
Will pollen levels change in San Juan Capistrano tomorrow?
On 12 October 2026, pollen conditions in San Juan Capistrano will be different from today, with ambrosia at moderate levels
Is pollen expected to decrease in San Juan Capistrano 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 Juan Capistrano?
On 11 October 2026, Ambrosia is the dominant pollen source in San Juan Capistrano. grass are also present but at lower levels. artemisia are not currently active.
When is pollen season in San Juan Capistrano?
How often is the San Juan Capistrano pollen forecast updated?
The San Juan Capistrano pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in San Juan Capistrano 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 Juan Capistrano 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 Juan Capistrano, 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).
