Name: Pollen forecast for Merton (2026-05-20)
Creator: Pollen Count
Published: 2026-05-20T14:02:58Z
License: https://pollencount.org/terms/

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About Pollen in Merton

Merton’s spring allergy profile is dominated by Birch and Oak pollen, peaking March-May from extensive street trees and woodlands, notably Wimbledon Common and Morden Hall Park; summer sees high Grass pollen counts, prevalent May-July from open spaces, Mitcham Common, and River Wandle riparian zones.

Urban topography and the Wandle Valley microclimate can trap and concentrate local pollen plumes; prevailing south-westerly winds also transport regional allergens. Autumn’s late-season challenge is Mould spores, peaking September-November due to damp leaf litter decomposition in green spaces and shaded urban environments.

HIGH

13 active species

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4-Day Forecast:

Morning

Grass MED

Tree V.HI

Weed LOW

Afternoon

Grass MED

Tree HIGH

Weed LOW

Evening

Grass LOW

Tree MED

Weed LOW

Species	Level	Count
🌳 Holm Oak	HIGH	70 grains/m³
🌳 English Oak	HIGH	70 grains/m³
🌳 London Plane	HIGH	61 grains/m³
🌳 White Oak	MED	45 grains/m³
🌳 Paper Birch	MED	30 grains/m³
+35 more tracked Downy Birch Perennial Ryegrass Ribwort Plantain Cock's-foot Grass (mixed) Common Sorrel Pigweed Stinging Nettle Box Elder Alder Common Ragweed Western Ragweed Giant Ragweed Sagebrush Mugwort Silver Birch Australian Pine Japanese Cypress Fat Hen Hazel Japanese Cedar Mediterranean Cypress Bermuda Grass Ash Mountain Cedar White Mulberry Olive Pellitory-of-the-wall Upright Pellitory Parthenium Weed Timothy Grass Black Poplar Mesquite Russian Thistle Field Elm All species in the app: Android iOS
🌳 Holm Oak	HIGH	79 grains/m³
🌳 English Oak	HIGH	79 grains/m³
🌳 London Plane	HIGH	68 grains/m³
🌳 White Oak	HIGH	51 grains/m³
🌳 Paper Birch	MED	33 grains/m³
+35 more tracked Downy Birch Perennial Ryegrass Ribwort Plantain Cock's-foot Common Sorrel Grass (mixed) Pigweed Stinging Nettle Box Elder Alder Common Ragweed Western Ragweed Giant Ragweed Sagebrush Mugwort Silver Birch Australian Pine Japanese Cypress Fat Hen Hazel Japanese Cedar Mediterranean Cypress Bermuda Grass Ash Mountain Cedar White Mulberry Olive Pellitory-of-the-wall Upright Pellitory Parthenium Weed Timothy Grass Black Poplar Mesquite Russian Thistle Field Elm All species in the app: Android iOS
🌳 Holm Oak	HIGH	70 grains/m³
🌳 English Oak	HIGH	70 grains/m³
🌳 London Plane	HIGH	60 grains/m³
🌳 White Oak	MED	45 grains/m³
🌳 Paper Birch	MED	30 grains/m³
+35 more tracked Downy Birch Perennial Ryegrass Ribwort Plantain Cock's-foot Common Sorrel Pigweed Grass (mixed) Stinging Nettle Box Elder Alder Common Ragweed Western Ragweed Giant Ragweed Sagebrush Mugwort Silver Birch Australian Pine Japanese Cypress Fat Hen Hazel Japanese Cedar Mediterranean Cypress Bermuda Grass Ash Mountain Cedar White Mulberry Olive Pellitory-of-the-wall Upright Pellitory Parthenium Weed Timothy Grass Black Poplar Mesquite Russian Thistle Field Elm All species in the app: Android iOS
🌳 Holm Oak	MED	33 grains/m³
🌳 English Oak	MED	33 grains/m³
🌳 London Plane	MED	28 grains/m³
🌳 White Oak	MED	21 grains/m³
🌳 Paper Birch	MED	14 grains/m³
+35 more tracked Downy Birch Perennial Ryegrass Ribwort Plantain Cock's-foot Grass (mixed) Common Sorrel Pigweed Stinging Nettle Box Elder Alder Common Ragweed Western Ragweed Giant Ragweed Sagebrush Mugwort Silver Birch Australian Pine Japanese Cypress Fat Hen Hazel Japanese Cedar Mediterranean Cypress Bermuda Grass Ash Mountain Cedar White Mulberry Olive Pellitory-of-the-wall Upright Pellitory Parthenium Weed Timothy Grass Black Poplar Mesquite Russian Thistle Field Elm All species in the app: Android iOS

Last updated: 14:02 UTC

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

Map of Merton (51.394335°, -0.128365°)

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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