Portsmouth pollen forecast — Strawbery Banke Museum neighborhood
Pollen Today
Today (20 September) pollen in Strawbery Banke Museum, Portsmouth is moderate; ragweed is moderate; grass is low.
Pollen Tomorrow
Tomorrow (21 September 2026) ragweed remains moderate, grass increasing, mugwort at low levels.
7-Day Trend
Over the next week grass, mugwort, and ragweed 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 | 20/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Moderate | 38/100 |
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 | 30/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 11/100 | |
| Ragweed (Ambrosia) | Moderate | 48/100 |
Local Environmental Conditions
Strawbery Banke Museum is a colonial seaport with mixed hardwood and salt marsh. Ocean influence moderates pollen on the coast. Tree pollen builds inland in May; harbor breezes help. A shorter season than Boston but similar species mix.
The pollen season at Strawbery Banke Museum mirrors Portsmouth overall, starting with maple and elm in March before birch and oak peaks during April and May. Grass follows, peaking through June and July, while ragweed and mugwort keep weed pollen elevated into September. Cold winters give way to a fast, concentrated spring pollen ramp-up across the region, a defining feature of the local season.
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Frequently Asked Questions About Pollen in New Hampshire
Is pollen high in Portsmouth right now?
On 20 September 2026, overall pollen levels in Portsmouth are moderate. Ambrosia is the main contributor to airborne pollen, while grass remain at lower levels
Will pollen levels change in Portsmouth tomorrow?
On 21 September 2026, pollen conditions in Portsmouth will be different from today, with ambrosia at moderate levels, artemisia at low levels and grass increasing
Is pollen expected to decrease in Portsmouth this week?
According to the five-day outlook, ambrosia, artemisia, and grass pollen levels are expected to gradually decrease, suggesting improving conditions later in the week.
Which pollen types are currently active in Portsmouth?
On 20 September 2026, Ambrosia is the dominant pollen source in Portsmouth. grass are also present but at lower levels. artemisia are not currently active.
When is pollen season in Portsmouth?
How often is the Portsmouth pollen forecast updated?
The Portsmouth pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Portsmouth 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 Portsmouth 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 Portsmouth, 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).
