Lower Merion Township pollen forecast — Penn Wynne neighborhood
Pollen Today
Today (20 September) pollen in Penn Wynne, Lower Merion Township is high; ragweed is high; grass is moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) grass declining, ragweed declining, mugwort no longer expected.
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 | 41/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 7/100 |
| Ragweed (Ambrosia) | High | 51/100 |
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) | Low | 15/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | Low | 23/100 |
Local Environmental Conditions
Located just around the area, this area has hazel and willow grow along the bank, contributing some of the season's earliest allergenic pollen. Oak and birch dominating the treeline, both heavy contributors to the spring pollen load, close to home here. Well-kept lawns and ornamental trees in this park add their share of grass and ragweed pollen; this sits in the surrounding area.
The waterside hazel and willow are consistently first to release pollen each year, climbing steadily from late winter into March. Further into spring, the area's oak and birch stands drive the pollen count, peaking in the heart of spring, generally April into May. As spring turns to summer, grass pollen rises toward its June high, and then ragweed picks up the slack, running from mid-August through October.
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Resource Hub
Pollen forecast neighborhoods 16 neighborhoods
Sports venues in Lower Merion Township 1 sports venue
Frequently Asked Questions About Pollen in Pennsylvania
Is pollen high in Lower Merion Township right now?
On 20 September 2026, overall pollen levels in Lower Merion Township are high. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Lower Merion Township tomorrow?
On 21 September 2026, pollen conditions in Lower Merion Township will be different from today, with ambrosia, grass continuing to decline
Is pollen expected to decrease in Lower Merion Township 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 Lower Merion Township?
On 20 September 2026, Ambrosia is the dominant pollen source in Lower Merion Township. grass and artemisia are also present but at lower levels.
When is pollen season in Lower Merion Township?
How often is the Lower Merion Township pollen forecast updated?
The Lower Merion Township pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Lower Merion Township 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 Lower Merion Township 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 Lower Merion Township, 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).
