San Jose pollen forecast — Bernal-Gulnac-Joice Ranch neighborhood
Pollen Today
Today (20 September) pollen in Bernal-Gulnac-Joice Ranch, San Jose is moderate; grass and ragweed are moderate.
Pollen Tomorrow
Tomorrow (21 September 2026) grass remains moderate, ragweed remains moderate, mugwort at low levels.
7-Day Trend
Over the next week grass, mugwort, and ragweed will increase.
Explore Forecasts
Air Quality & Mold
Pollen for Neighborhoods
Get More in Our App
Local pollen and air quality forecasts, interactive pollen maps and route profiles
Features and forecast availability vary by region.
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 | 39/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Moderate | 36/100 |
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 | 43/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 5/100 | |
| Ragweed (Ambrosia) | Moderate | 41/100 |
Local Environmental Conditions
Here, not far from here, a park combining lawn grass and planted trees, both minor but real contributors to pollen here. The broader area tends to mirror this pattern, with only minor local variation. Seasonal timing here generally tracks the wider region, give or take a week or so. Surrounding neighborhoods with similar tree cover typically see a closely comparable pollen mix.
Average temperatures range from about 9°C in January to 20°C in August, and most of the 589 mm annual rainfall falls in the cooler months around January. Pollen activity typically picks up as temperatures climb out of the January low, from around February onward.
Get pollen & AQ on Strava
Follow your environmental exposure and performance with the free Airmine-Strava integration. See your pollen and air quality exposure for every Strava activity.
Resource Hub
Pollen forecast neighborhoods 80 neighborhoods
Sports venues in San Jose 1 sports venue
Frequently Asked Questions About Pollen in California
Is pollen high in San Jose right now?
On 20 September 2026, overall pollen levels in San Jose are moderate. Ambrosia is the main contributor to airborne pollen, while grass remain at lower levels
Will pollen levels change in San Jose tomorrow?
On 21 September 2026, pollen conditions in San Jose will be different from today, with ambrosia at moderate levels, artemisia at low levels, grass at moderate levels
Is pollen expected to decrease in San Jose 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 Jose?
On 20 September 2026, Ambrosia is the dominant pollen source in San Jose. grass are also present but at lower levels. artemisia are not currently active.
When is pollen season in San Jose?
How often is the San Jose pollen forecast updated?
The San Jose pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in San Jose 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 Jose 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 Jose, 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).
