Porterville pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Porterville is high; grass and ragweed are high; mugwort is moderate.
Pollen Tomorrow
Tomorrow (21 September 2026) ragweed remains high, grass declining, mugwort declining.
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) | High | 64/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Moderate | 34/100 |
| 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 | 31/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 1/100 | |
| Ragweed (Ambrosia) | High | 57/100 |
Local Environmental Conditions
Porterville's Sierra Nevada foothill setting features blue oak, gray pine, and chaparral scrub as the main tree pollen sources, with exposure varying between the foothill woodland and chaparral residential areas and the more built-up commercial corridors along Highway 65. The Tule River corridor provides locally significant green space, while the transition from valley agricultural land to foothill woodland creates distinct pollen zones across the city.
Porterville's San Joaquin Valley foothill setting produces a season opening in January with oak and olive before grass from surrounding Tulare County farmland peaks through April and May. Mugwort extends exposure into September, while the hot, dry foothills summer suppresses most pollen by July and the Sierra Nevada foothills backdrop means the season begins slightly later than in the valley floor below.
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Pollen forecast neighborhoods 2 neighborhoods
Frequently Asked Questions About Pollen in California
Is pollen high in Porterville right now?
On 20 September 2026, overall pollen levels in Porterville are high. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Porterville tomorrow?
On 21 September 2026, pollen conditions in Porterville will be different from today, with ambrosia at high levels and artemisia, grass continuing to decline
Is pollen expected to decrease in Porterville 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 Porterville?
On 20 September 2026, Ambrosia is the dominant pollen source in Porterville. grass and artemisia are also present but at lower levels.
When is pollen season in Porterville?
How often is the Porterville pollen forecast updated?
The Porterville pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Porterville 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 Porterville 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 Porterville, 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).
