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About Pollen in Harrow

Harrow’s allergy profile sees dominant spring Birch and Oak pollen (March-May), sourced from extensive woodlands at Bentley Priory Nature Reserve and Harrow Weald Common; followed by peak summer Grass pollen (June-August) from local playing fields and River Pinn’s marginal meadows.

Topography, including Harrow Hill’s elevation and sheltered suburban parks, can localise and intensify pollen concentrations; late-season mould spores (Sept-Nov) elevate from damp leaf decomposition in parklands and shaded urban areas.

V.HI

11 active species

Refreshing live forecast…

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4-Day Forecast:

Morning

Grass LOW

Tree X.HI

Weed LOW

Afternoon

Grass LOW

Tree V.HI

Weed LOW

Evening

Grass LOW

Tree MED

Weed LOW

Species	Level	Count
🌳 Silver Birch	V.HI	109 grains/m³
🌳 Downy Birch	V.HI	103 grains/m³
🌳 Paper Birch	HIGH	81 grains/m³
🌳 English Oak	HIGH	67 grains/m³
🌳 Holm Oak	MED	33 grains/m³
+35 more tracked Black Poplar Box Elder London Plane White Oak Ash Field Elm Alder Pigweed Common Ragweed Western Ragweed Giant Ragweed Sagebrush Mugwort Australian Pine Japanese Cypress Fat Hen Hazel Japanese Cedar Mediterranean Cypress Bermuda Grass Cock's-foot Mountain Cedar Perennial Ryegrass White Mulberry Olive Pellitory-of-the-wall Upright Pellitory Parthenium Weed Timothy Grass Ribwort Plantain Grass (mixed) Mesquite Common Sorrel Russian Thistle Stinging Nettle All species in the app: Android iOS
🌳 Silver Birch	V.HI	166 grains/m³
🌳 Downy Birch	V.HI	156 grains/m³
🌳 Paper Birch	V.HI	122 grains/m³
🌳 English Oak	V.HI	102 grains/m³
🌳 Holm Oak	HIGH	50 grains/m³
+35 more tracked Black Poplar Box Elder London Plane White Oak Ash Field Elm Alder Pigweed Common Ragweed Western Ragweed Giant Ragweed Sagebrush Mugwort Australian Pine Japanese Cypress Fat Hen Hazel Japanese Cedar Mediterranean Cypress Bermuda Grass Cock's-foot Mountain Cedar Perennial Ryegrass White Mulberry Olive Pellitory-of-the-wall Upright Pellitory Parthenium Weed Timothy Grass Ribwort Plantain Grass (mixed) Mesquite Common Sorrel Russian Thistle Stinging Nettle All species in the app: Android iOS
🌳 Silver Birch	V.HI	133 grains/m³
🌳 Downy Birch	V.HI	125 grains/m³
🌳 Paper Birch	HIGH	99 grains/m³
🌳 English Oak	HIGH	82 grains/m³
🌳 Holm Oak	MED	40 grains/m³
+35 more tracked Box Elder Black Poplar London Plane White Oak Ash Field Elm Alder Pigweed Common Ragweed Western Ragweed Giant Ragweed Sagebrush Mugwort Australian Pine Japanese Cypress Fat Hen Hazel Japanese Cedar Mediterranean Cypress Bermuda Grass Cock's-foot Mountain Cedar Perennial Ryegrass White Mulberry Olive Pellitory-of-the-wall Upright Pellitory Parthenium Weed Timothy Grass Ribwort Plantain Grass (mixed) Mesquite Common Sorrel Russian Thistle Stinging Nettle All species in the app: Android iOS
🌳 Silver Birch	HIGH	98 grains/m³
🌳 Downy Birch	HIGH	93 grains/m³
🌳 Paper Birch	HIGH	73 grains/m³
🌳 English Oak	HIGH	60 grains/m³
🌳 Holm Oak	MED	30 grains/m³
+35 more tracked Black Poplar Box Elder London Plane White Oak Ash Field Elm Alder Pigweed Common Ragweed Western Ragweed Giant Ragweed Sagebrush Mugwort Australian Pine Japanese Cypress Fat Hen Hazel Japanese Cedar Mediterranean Cypress Bermuda Grass Cock's-foot Mountain Cedar Perennial Ryegrass White Mulberry Olive Pellitory-of-the-wall Upright Pellitory Parthenium Weed Timothy Grass Ribwort Plantain Grass (mixed) Mesquite Common Sorrel Russian Thistle Stinging Nettle All species in the app: Android iOS

Last updated: 14:02 UTC

4-Day Forecast	Tree	Grass	Weed
Wed 20 May	V.HI	LOW	LOW
Thu 21 May	V.HI	LOW	LOW
Fri 22 May	V.HI	LOW	LOW
Sat 23 May	HIGH	LOW	LOW

Map of Harrow (51.633972°, -0.304218°)

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What Pollen Levels Mean

LOW Symptoms are unlikely

MED Moderate risk of symptoms

HIGH Widespread symptoms likely

V.HI Expect significant symptoms

X.HI Extremely high symptom likelihood & severity