Block Island pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Block Island is high; ragweed is high; grass is moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) grass remains moderate, mugwort remains low, ragweed declining.
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 | 42/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 18/100 |
| Ragweed (Ambrosia) | High | 53/100 |
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 | 29/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 6/100 | |
| Ragweed (Ambrosia) | Moderate | 40/100 |
Local Environmental Conditions
Block Island's setting on a small glacial island 12 miles off the Rhode Island coast supports coastal grassland and heath, bayberry, and wild rose as the leading local vegetation, all factoring into the pollen count through the year. Local parks and open ground tend to see higher pollen counts than the denser urban core. As with most of the region, counts tend to build gradually rather than spike overnight.
The pollen calendar in Block Island opens with maple and elm starting March with birch and oak joining in and continuing through 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 throughout the year.
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Frequently Asked Questions About Pollen in Rhode Island
Is pollen high in Block Island right now?
On 20 September 2026, overall pollen levels in Block Island are high. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Block Island tomorrow?
On 21 September 2026, pollen conditions in Block Island will be different from today, with artemisia at low levels, grass at moderate levels and ambrosia continuing to decline
Is pollen expected to decrease in Block Island this week?
According to the five-day outlook, ambrosia and grass 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 Block Island?
On 20 September 2026, Ambrosia is the dominant pollen source in Block Island. grass and artemisia are also present but at lower levels.
When is pollen season in Block Island?
How often is the Block Island pollen forecast updated?
The Block Island pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Block Island 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 Block Island 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 Block Island, 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).
