Pollen Count & Forecast for Los Angeles

Los Angeles’ spring allergy season (February-May) is dominated by Oak and Sycamore pollen; Coast Live Oak (Quercus agrifolia) prolific in Griffith Park and the Santa Monica Mountains; California Sycamore (Platanus racemosa) widespread along the Los Angeles River. Walnut (Juglans) contributes from the San Fernando Valley. Summer (May-September) sees high Bermuda Grass (Cynodon dactylon) and Sagebrush (Artemisia) pollen levels, originating from unmanaged hillsides and Elysian Park.

The surrounding mountain ranges trap pollen and pollutants against the coast; Santa Ana winds carry dust and spores from the desert. Autumn and winter see elevated Mould (Alternaria, Cladosporium) spore counts, from coastal moisture and decaying plant matter in shaded canyons and drainage channels.