Hanover pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Hanover is low; ragweed is low.
Pollen Tomorrow
Tomorrow (21 September 2026) ragweed increasing, grass at low levels, mugwort at low levels.
7-Day Trend
Over the next week grass, mugwort, and ragweed will decrease.
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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) | None | 0/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Low | 19/100 |
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) | Low | 14/100 | |
| Ragweed (Ambrosia) | High | 51/100 |
Local Environmental Conditions
The vegetation around Hanover, on hills above the Connecticut River valley, is dominated by sugar maple and white pine and paper birch, with eastern hemlock adding further seasonal pollen exposure. Seasonal timing here follows the broader regional pattern typical of this part of the country. The mix of native and introduced species here is fairly typical for this part of the country.
Pollen season in Hanover starts with maple and elm in March with birch and oak following close behind through April and May. A grass pollen peak follows through June and July; ragweed and mugwort keep weed pollen elevated into September. A relatively short growing season compresses tree, grass, and weed pollen into a more intense stretch, shaping conditions across the city.
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Frequently Asked Questions About Pollen in New Hampshire
Is pollen high in Hanover right now?
On 20 September 2026, overall pollen levels in Hanover are low. Ambrosia is the main contributor to airborne pollen
Will pollen levels change in Hanover tomorrow?
On 21 September 2026, pollen conditions in Hanover will be different from today, with artemisia at low levels, grass at low levels and ambrosia increasing
Is pollen expected to decrease in Hanover 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 Hanover?
On 20 September 2026, Ambrosia is the dominant pollen source in Hanover. artemisia and grass are not currently active.
When is pollen season in Hanover?
How often is the Hanover pollen forecast updated?
The Hanover pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Hanover 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 Hanover 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 Hanover, 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).
