Hempstead, New York pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Hempstead, New York is moderate; grass and ragweed are moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) levels are similar to today.
7-Day Trend
Over the next week mugwort will increase; grass 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) | Moderate | 38/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 7/100 |
| Ragweed (Ambrosia) | Moderate | 49/100 |
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 | 32/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 1/100 | |
| Ragweed (Ambrosia) | Moderate | 41/100 |
Local Environmental Conditions
Hempstead's suburban setting on Long Island features oak and maple as the main tree pollen sources in parks and along residential streets, with exposure varying between these green areas and the more built-up town centre. Surrounding Nassau County woodland and the flat Long Island landscape contribute substantial grass and tree pollen, while the proximity to the Atlantic coast means onshore winds can periodically disperse urban pollen.
Hempstead's pollen season on Long Island opens with maple and birch from late February, followed by oak through April and May. Grass pollen peaks through June and July, with ragweed extending the season into September. The Atlantic coast position means onshore winds can periodically moderate pollen levels, while surrounding Nassau County woodland and the flat Long Island landscape allow pollen to disperse readily across the area.
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Frequently Asked Questions About Pollen in New York
Is pollen high in Hempstead, New York right now?
On 20 September 2026, overall pollen levels in Hempstead, New York are moderate. Grass is the main contributor to airborne pollen, while ambrosia and artemisia remain at lower levels
Will pollen levels change in Hempstead, New York tomorrow?
On 21 September 2026, pollen conditions in Hempstead, New York will be similar to today, with artemisia at low levels, grass at moderate levels, ambrosia at moderate levels
Is pollen expected to decrease in Hempstead, New York this week?
According to the five-day outlook, grass and ambrosia pollen levels are expected to gradually decrease, while artemisia pollen will increase, suggesting mixed conditions later in the week.
Which pollen types are currently active in Hempstead, New York?
On 20 September 2026, Grass is the dominant pollen source in Hempstead, New York. ambrosia and artemisia are also present but at lower levels.
When is pollen season in Hempstead, New York?
How often is the Hempstead, New York pollen forecast updated?
The Hempstead, New York pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Hempstead, New York 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 Hempstead, New York 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 Hempstead, New York, 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. |
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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).
