Pollen Count & Forecast for Watford, Harrow

Watford’s allergy profile sees peak tree pollen activity March-May; Birch and Oak are dominant, originating from Cassiobury Park’s extensive woodlands and Oxhey Park’s mature tree lines; Grass pollen peaks May-July, widely dispersed from Watford Fields, River Colne riverbanks, and residential lawns.

The urban-suburban interface, particularly near Watford Junction, can create pollen traps; River Colne valley topography influences localised pollen distribution; late-season mould spores (Sept-Nov) derive from decaying leaf litter in Whippendell Woods and widespread damp domestic environments.