Mild
Mild pollen — sensitive individuals may notice
Grass pollen is the main trigger · Tomorrow ↑ · Updated 13 hours ago
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Pollen levels in Boulder are currently low. Most people should not experience allergy symptoms from pollen.
Tree pollen: Low. Grass pollen: Moderate. Weed pollen: None.
Yes, pollen conditions in Boulder are expected to worsen tomorrow.
Boulder, Colorado sits at the foot of the Rocky Mountains at roughly 5,400 feet, and its semi-arid climate, high UV exposure, and gusty Chinook winds create a distinctive allergy profile that can carry pollen long distances from the plains and foothills.
Tree pollen kicks off the season in early spring, typically from late February through May, with juniper and mountain cedar leading the way, followed by cottonwood, aspen, elm, box elder, ash, and oak as temperatures climb.
Grass pollen takes over from late May into July, dominated by Kentucky bluegrass, timothy, orchard grass, and brome, which thrive in irrigated lawns and along the Front Range open spaces.
By August, weed season ramps up and continues through the first hard frost in October, driven heavily by ragweed, sagebrush, Russian thistle (tumbleweed), kochia, and lamb's quarters.
Late spring often brings overlapping tree and grass pollen, intensifying symptoms for many residents.
Beyond pollen, Boulder's dry air stirs up significant dust and particulate matter, while summer wildfire smoke and occasional Front Range ozone add to respiratory irritation; indoor and outdoor molds spike after monsoon rains.
Overall, Boulder's allergy profile is defined by a long, wind-driven pollen season compounded by dust, smoke, and dryness.