Harrow pollen forecast - today, tomorrow and the week ahead
Today (25 June) pollen in Harrow is medium; grass is medium. Tomorrow (26 June 2026) levels are similar - grass increasing, cypress at low levels. Over the following five days cypress and grass will decrease. Forecasts are calculated by Airmine using satellites to map local vegetation and determine pollen season onset.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
Harrow's parks, including Harrow-on-the-Hill and Stanmore Country Park, feature oak and birch as the main tree pollen sources, with exposure varying between these green areas and the more densely built parts of the borough. The green belt and farmland of Hertfordshire to the north contribute additional grass and tree pollen that moves into the borough under northerly winds.
Today - 25 June
-
Alder (Alnus):
None
0/100
-
Birch (Betula):
None
0/100
-
Hazel (Corylus):
None
0/100
-
Cypress (Cupressaceae):
None
0/100
-
Grass (Poaceae):
Medium
31/100
-
Willow (Salicaceae):
None
0/100
High pollen levels may trigger sneezing, itchy eyes, and congestion. Airmine's neighbourhood estimates use satellites to map local vegetation and a statistical prediction model, updated four times daily.
Tomorrow - 26 June
-
Alder (Alnus):
None
0/100
-
Birch (Betula):
None
0/100
-
Hazel (Corylus):
None
0/100
-
Cypress (Cupressaceae):
Low
14/100
-
Grass (Poaceae):
High
57/100
-
Willow (Salicaceae):
None
0/100
Frequently Asked Questions
Is pollen high in Harrow right now?
On 25 June 2026, overall pollen levels in Harrow are moderate. Grass is the main contributor to airborne pollen
Will pollen levels change in Harrow tomorrow?
On 26 June 2026, pollen conditions in Harrow will be different from today, with cypress at low levels and grass increasing
Is pollen expected to decrease in Harrow this week?
According to the five-day outlook, cypress and grass pollen levels are expected to gradually decrease, suggesting improving conditions later in the week.
Which pollen types are currently active in Harrow?
On 25 June 2026, Grass is the dominant pollen source in Harrow. hazel, cypress, willow, alder, and birch are not currently active.
When is pollen season in Harrow?
How often is the Harrow pollen forecast updated?
The Harrow pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Harrow 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 Harrow 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 Harrow, 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.
Want to see pollen forecasts for other cities in United Kingdom?
Check pollen in other popular cities:
Data provided by Airmine — Last update: 25 Jun 2026, 09:01 CET (Data is updated four times daily.)
This page provides the latest public pollen forecast for Harrow.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.