Name: Pollen forecast for Colchester (2026-05-20)
Creator: Pollen Count
Published: 2026-05-20T14:02:49Z
License: https://pollencount.org/terms/

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About Pollen in Colchester

Colchester experiences peak seasonal allergies from March to July. Spring brings dominant arboreal pollen: Birch and Hazel are prolific March-April from High Woods Country Park and urban street trees; Oak and Plane pollen follow April-May, prevalent in Castle Park and along the Roman walls. Early summer (May-July) sees high grass pollen counts, originating from the River Colne floodplains and surrounding agricultural meadows.

The city’s historical urban fabric, including the Roman walls and dense housing, can create sheltered microclimates, trapping pollen and intensifying localised exposure. Late summer through autumn introduces elevated mould spore levels; these originate from damp leaf litter in parks and decomposing vegetation within the Colne Valley’s humid environments, prolonging allergy symptoms until winter.

HIGH

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 HIGH

Weed LOW

Evening

Grass LOW

Tree MED

Weed LOW

Species	Level	Count
🌳 Silver Birch	HIGH	92 grains/m³
🌳 Downy Birch	HIGH	65 grains/m³
🌳 Paper Birch	HIGH	51 grains/m³
🌳 English Oak	MED	40 grains/m³
🌳 Ash	MED	31 grains/m³
+35 more tracked Black Poplar Box Elder Holm Oak Field Elm London Plane White Oak 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	161 grains/m³
🌳 Downy Birch	V.HI	113 grains/m³
🌳 Paper Birch	HIGH	88 grains/m³
🌳 English Oak	HIGH	69 grains/m³
🌳 Ash	HIGH	53 grains/m³
+35 more tracked Black Poplar Box Elder Holm Oak Field Elm London Plane White Oak 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	164 grains/m³
🌳 Downy Birch	V.HI	115 grains/m³
🌳 Paper Birch	HIGH	90 grains/m³
🌳 English Oak	HIGH	71 grains/m³
🌳 Ash	HIGH	54 grains/m³
+35 more tracked Black Poplar Box Elder Holm Oak Field Elm London Plane White Oak 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	95 grains/m³
🌳 Downy Birch	HIGH	67 grains/m³
🌳 Paper Birch	HIGH	52 grains/m³
🌳 English Oak	MED	41 grains/m³
🌳 Ash	MED	32 grains/m³
+35 more tracked Black Poplar Box Elder Holm Oak Field Elm London Plane White Oak 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	HIGH	LOW	LOW
Thu 21 May	V.HI	LOW	LOW
Fri 22 May	V.HI	LOW	LOW
Sat 23 May	HIGH	LOW	LOW

Map of Colchester (51.883214°, 0.85318°)

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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