Boulder, CO Pollen Count

What is the Boulder pollen count today?

The Boulder pollen count today is 21 out of 100 (Low) on the Pollen Atlas Total Pollen Index, driven mainly by Ragweed.

Short answer for anyone searching pollen count today Boulder: this page is updated every morning with the day’s modelled reading.

Boulder allergies today

Boulder allergies today are set by the same reading as the pollen count above: the Total Pollen Index is 21 (Low), driven mainly by Ragweed. When people ask about Boulder allergies, this is the number that answers them — one daily index built from today’s tree, grass, weed and mold readings for Boulder.

Allergies in Boulder follow the Colorado calendar set out below — the chapters, the plants behind them, and the 5-day forecast on this page show whether today is typical for the season or an exception to it. If you are checking allergies today in Boulder before heading outdoors, the split at the top of this page is the part to read: it shows which pollen is doing the work today, not just how high the total sits.

Read the five-day table on this page as the Boulder allergy forecast: today reads 21 (Low), and the day-by-day outlook shows whether Boulder allergies are set to ease or build across the week — the days to plan outdoor time around are the ones where the index steps down, not just today.

In practice, the allergy count Boulder today records is this same combined reading — tree, grass, weed and mold in one index.

The Boulder allergy count today is 21 (Low) — the same Total Pollen Index as the pollen count above, in one combined reading.

Pollen count today Boulder: the 5-day forecast

Pollen Atlas forecasts Boulder’s pollen count to peak on Saturday at 23 (Low) over the next 5 days.

Pollen by type in Boulder

• Boulder tree pollen count
• Boulder grass pollen count
• Boulder ragweed pollen count

What is driving Boulder’s pollen today

The shape of today’s 21 (Low) is set by weed pollen at 27 (Low on its own scale) — about 96% of the four category readings added together, 26.4 points clear of the next category, tree pollen at 0.6. A weed-led total is the classic late-year shape: tree and grass pollen have usually receded, leaving weed pollen — and on damp days mold — to make up most of what the index records. Weed pollen leading in November runs against the usual calendar — the Colorado weed chapter runs August to October — so today’s lead is the model outranking the pattern, and this page reports the modelled reading first.

Plant-level detail is not in today’s feed for Boulder, so the drivers have to be read from the category split above. The Colorado guide’s account of Colorado names juniper, arriving ahead of the local tree season, and the ragweed and sagebrush-family weeds of late summer — the pollens behind readings of this shape in this state — and the split shows how much of today’s total each category is actually carrying.

Across the five-day window the Total Pollen Index runs from 21 to 23, never changing band. Today’s 21 sits 1 point below the window’s average of 22.2 — a steady window, in which one day reads much like the next.

Plants affecting Boulder now

Detailed plant-by-plant readings for Boulder were not returned in today\u2019s source data, so this section summarises the pollen types the index above is built from instead of listing individual plants.

Tree pollen is one of the categories with a non-zero reading today, at 0.6 (Low).

Grass pollen is one of the categories with a non-zero reading today, at 0.6 (Low).

Weed pollen is one of the categories with a non-zero reading today, at 27 (Low).

In the Mountain West pattern, the plants that typically shape this city’s year are spring trees and late-spring grasses in a compressed warm-season window — named here as regional context only, not as today\u2019s measurements.

Plant detail returns here automatically on any day the source data includes it.

Every pollen type, with photos and seasons: the pollen directory.

Boulder pollen through the year

Chapter by chapter, the Boulder pollen year runs like this:

• Juniper can arrive in late winter, and the main tree wave builds in spring — as late as April at Denver’s altitude.
• Grasses follow in a compressed early-summer run.
• Ragweed and sagebrush-family weeds close the year from late summer.

The Colorado allergy season guide names juniper, arriving ahead of the local tree season, and the ragweed and sagebrush-family weeds of late summer. Altitude compresses Colorado’s season rather than removing it: the waves arrive late — Denver’s tree pollen typically builds in April — and end with early frosts, but they run in a tight sequence. The season ends with the first hard frosts, which stop the late-summer weeds — Denver usually reaches frost in fall, while mountain towns can frost far earlier.

November falls between the main chapters of the Colorado pollen year — the tail of one and the approach of the next — so the calendar alone explains little today, and the modelled split above carries the story. Between them, the three chapters cover 9 months of the Colorado year, February to October — leaving a quiet gap of roughly 3 months in the depth of the off-season. The full calendar is set out in the Colorado allergy season guide.

How to read this index

Pollen Atlas reports the Boulder pollen count on a Total Pollen Index from 0 to 100, built from separate tree, grass and weed readings. The total is a summary, not an average of the three: a single strong category can lift it, and three quiet categories can hold it down whatever the month. Index values are a modelled pollen risk index computed by Pollen Atlas from open weather, vegetation and phenology data, calibrated against CDC/NAB season data, with plant detail by the Google Pollen API. The index is a modelled 0–100 scale, not a measured count, and figures update through the day, so a morning and an evening visit to this page can legitimately show different numbers.

Boulder in today’s national picture

At 21 (Low), Boulder ranks joint 47143rd of the 90896 cities Pollen Atlas tracks today — in the middle of the national table. The highest reading in the country today is Serpa, Portugal at 53, and the lowest is Galiakberovo, Russia at 5. The whole table spans 48 points today — a wide-open day, when the top and bottom of the table are effectively in different seasons.

Around Boulder: Valmont, CO (2 miles away) reads 23 (Low); Pine Brook Hill, CO (3 miles away) reads 21 (Low); Seven Hills, CO (4 miles away) reads 21 (Low). Boulder reads 2 points lower than its nearest tracked neighbour today. Across Colorado’s 479 tracked cities, today runs from 5 in Parker to 32 in Dillon.

Pollen totals are population numbers; symptoms are personal. The same reading can leave one Boulder resident untouched and floor another, depending on which pollens they are sensitised to. If this pattern finds you every season, allergists in Boulder, CO can test whether tree, grass, weed or mold is the category that matters for you — the four readings at the top of this page are the starting point for that conversation.

Boulder in its local area

Boulder is a city in Boulder County, Colorado. Its population is 106,274 (ACS 2023).

Across Colorado’s 479 tracked cities, Boulder ranks joint 204th today.

Like every Pollen Atlas city page, the Boulder, CO pollen count is refreshed each morning.

Nearby cities

• Valmont pollen count (2 miles away)
• Pine Brook Hill pollen count (3 miles away)
• Seven Hills pollen count (4 miles away)
• Paragon Estates pollen count (5 miles away)
• Gunbarrel pollen count (5 miles away)
• Tall Timber pollen count (5 miles away)

From Pollen Atlas News

• Colorado allergy season
• Ragweed season