Aliso Viejo pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Aliso Viejo is high; ragweed is high; grass is moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) levels are similar to today.
7-Day Trend
Over the next week grass, mugwort, and ragweed will increase.
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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 | 50/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 10/100 |
| Ragweed (Ambrosia) | High | 70/100 |
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) | Moderate | 40/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 1/100 | |
| Ragweed (Ambrosia) | High | 62/100 |
Local Environmental Conditions
Aliso Viejo's Orange County California coastal hillside setting features coastal sage scrub, Toyon, and Torrey pine as the main pollen sources, with exposure varying between the native coastal sage scrub canyon slopes and the more built-up residential and commercial corridors along Pacific Park Drive. The Aliso and Wood Canyons Wilderness Park provides a particularly significant native coastal sage scrub pollen source, creating distinct canyon-to-ridgeline pollen gradients across this planned hillside community.
Aliso Viejo's coastal Orange County California setting produces a season opening in January with olive and coastal sage before grass from surrounding land peaks through March and April. Mugwort extends exposure into September, while the strong Pacific marine influence moderates temperatures year-round and onshore ocean breezes frequently suppress pollen dispersal across this hillside coastal Orange County community throughout.
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Frequently Asked Questions About Pollen in California
Is pollen high in Aliso Viejo right now?
On 20 September 2026, overall pollen levels in Aliso Viejo are high. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Aliso Viejo tomorrow?
On 21 September 2026, pollen conditions in Aliso Viejo will be similar to today, with artemisia at low levels, grass at moderate levels, ambrosia at high levels
Is pollen expected to decrease in Aliso Viejo 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 Aliso Viejo?
On 20 September 2026, Ambrosia is the dominant pollen source in Aliso Viejo. grass and artemisia are also present but at lower levels.
When is pollen season in Aliso Viejo?
How often is the Aliso Viejo pollen forecast updated?
The Aliso Viejo pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Aliso Viejo 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 Aliso Viejo 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 Aliso Viejo, 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).
