Tamalpais-Homestead Valley, California Pollen Count

Frequently asked

When is pollen worst in Tamalpais-Homestead Valley?

Tamalpais-Homestead Valley's pollen season runs in three overlapping waves: tree pollen peaks Jan–Apr, grass pollen Mar–Jun, and weed (ragweed) pollen Aug–Oct. The single worst stretch for most people is the spring tree peak and the late-summer ragweed peak; the live count at the top of this page tells you which is active today.

What's pollinating in Tamalpais-Homestead Valley right now?

In June, grass pollen is in season in Tamalpais-Homestead Valley — the dominant allergen you're likely reacting to right now. The live index above (when available) confirms the day's actual count; this calendar reflects the typical peak windows for Tamalpais-Homestead Valley's climate region.

Is tree or grass pollen higher in Tamalpais-Homestead Valley in spring?

In spring, tree pollen usually dominates in Tamalpais-Homestead Valley — trees pollinate Jan–Apr, ahead of the grass peak (Mar–Jun). Late spring is the handoff: tree counts taper as grass climbs, so a bad April is more likely tree pollen and a bad late-May/June is more likely grass.

How do I reduce pollen exposure in Tamalpais-Homestead Valley?

Keep windows closed and run air conditioning on recirculate during peak season; counts are highest on dry, warm, windy mornings, so time outdoor activity for late afternoon or after rain, which washes pollen out of the air. A HEPA air purifier indoors, a saline nasal rinse after being outside, showering and changing clothes before bed, and starting antihistamines before your worst season begins all measurably cut symptoms.

What pollen index counts as high?

Pollen is reported on a categorical scale — None, Low, Moderate, High, and Very High. "High" and above means most allergy sufferers will notice symptoms even with brief outdoor exposure, and sensitized people should limit time outside and pre-medicate. "Low" to "Moderate" usually only affects highly sensitive individuals.