San Francisco pollen forecast — The Olympic Club – Lake Course neighborhood
Pollen Today
Today (20 September) pollen in The Olympic Club – Lake Course, San Francisco is moderate; ragweed is moderate; grass is low.
Pollen Tomorrow
Tomorrow (21 September 2026) grass increasing, ragweed increasing, mugwort at low levels.
7-Day Trend
Over the next week mugwort and ragweed will increase; grass will decrease.
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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) | Low | 18/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Moderate | 48/100 |
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 | 27/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 7/100 | |
| Ragweed (Ambrosia) | High | 57/100 |
Local Environmental Conditions
The Olympic Club's San Francisco western setting features Monterey cypress, coast live oak, and eucalyptus as the main pollen sources across the Lake Course, with exposure varying between the densely forested fairway corridors and the more open sections. The Pacific Ocean proximity means onshore marine winds frequently disperse pollen, while the coastal California climate advances the season and the dense tree canopy creates one of the more sheltered urban golf environments in California.
Situated a golf course in San Francisco, The Olympic Club – Lake Course shares the area's pollen timeline, beginning with acacia and oak in January then olive builds through February and March. Grass pollen rises through March and April, and light weed pollen continues into early autumn. A long dry summer follows the spring peak, holding pollen counts low until autumn rains return.
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Frequently Asked Questions About Pollen in California
Is pollen high in San Francisco right now?
On 20 September 2026, overall pollen levels in San Francisco are moderate. Ambrosia is the main contributor to airborne pollen, while grass remain at lower levels
Will pollen levels change in San Francisco tomorrow?
On 21 September 2026, pollen conditions in San Francisco will be different from today, with artemisia at low levels and ambrosia, grass increasing
Is pollen expected to decrease in San Francisco this week?
According to the five-day outlook, grass pollen levels are expected to gradually decrease, while ambrosia and artemisia pollen will increase, suggesting mixed conditions later in the week.
Which pollen types are currently active in San Francisco?
On 20 September 2026, Ambrosia is the dominant pollen source in San Francisco. grass are also present but at lower levels. artemisia are not currently active.
When is pollen season in San Francisco?
How often is the San Francisco pollen forecast updated?
The San Francisco pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in San Francisco 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 Francisco 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 Francisco, 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).
