Pollen Calendar

When each allergen is active in the US, weighted by your IgE sensitization — darker means an allergen you react to strongly is at peak. Seasons are generalized national ranges; your region will shift them.

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AllergenIgE (kU/L)ClassActive months
Rye Grass1006May, Jun, Jul
Timothy Grass1006May, Jun, Jul
Johnson Grass63.95May, Jun, Jul, Aug, Sep, Oct
Bermuda Grass23.54Apr, May, Jun, Jul, Aug, Sep
Walnut Tree9.613Apr, May, Jun
Olive7.043Mar, Apr, May, Jun
Grey Alder6.833Jan, Feb, Mar, Apr
Elm6.333Feb, Mar, Apr
Oak6.073Feb, Mar, Apr, May, Jun
Maple Leaf Sycamore5.663Mar, Apr, May
Box Elder5.413Mar, Apr, May
Acacia5.133Jan, Feb, Mar, Apr
Common Silver Birch5.113Mar, Apr, May
Cottonwood4.793Feb, Mar, Apr
Mountain Cedar2.722Jan, Feb, Nov, Dec
Mulberry1.92Feb, Mar, Apr, May
English Plantain7.63Apr, May, Jun, Jul, Aug, Sep
Sheep Sorrel7.513May, Jun, Jul
Lambs Quarter5.443Jun, Jul, Aug, Sep, Oct
Common Pigweed5.163Jul, Aug, Sep, Oct
Russian Thistle5.053Jul, Aug, Sep, Oct
Mugwort4.643Aug, Sep, Oct
Western Ragweed3.222Aug, Sep, Oct
Dust Mite24.54Year-round
Cat Dander1.362Year-round
Dog Dander0.72Year-round
Aspergillus Fumigatus0.110Year-round
Alternaria Alternata0.10May, Jun, Jul, Aug, Sep, Oct
Cladosporium Herbarum0.10Apr, May, Jun, Jul, Aug, Sep, Oct, Nov