Harrisburg, IL Pollen Count Today
Harrisburg, IL · Updated Saturday, November 7, 2026
Pollen Overview
Today's overall pollen level and the dominant type (trees, weeds, grass, or mold).
Total Pollen Index
The combined pollen level across all types (0–100).
Harrisburg, IL
Weeds Index
How active weeds pollen is today (0–100).
Harrisburg, IL
Pollen Types
Pick a pollen subtype to update the species forecast
5-Day Harrisburg Overall Pollen Forecast
Bars are colored by severity (Low/Moderate/High).
Pollen count Harrisburg residents check each morning
The Harrisburg pollen count today is 21 (Low). The main driver is Ragweed, with weed pollen at 27 today. That total sits on a narrow base: weed pollen is 27 while tree pollen is just 0.6 and grass pollen 2. Plant-by-plant detail for Harrisburg, IL follows, along with the outlook for the days ahead. Pollen Atlas updated this count on Saturday, November 7, 2026.
A Low band on the Pollen Atlas index means the Total Pollen Index has stayed in the lower part of the 0–100 scale. Readings in this band are built from low individual category values rather than from one large spike, and the category split above matters more than the headline number: a low total can still contain one category, such as weed pollen or mold, reading noticeably higher than the rest, which is why the split is printed on every Harrisburg page.
Fall is ragweed season across most of the United States: ragweed plants release pollen from late summer into autumn, and weed pollen is typically the last major outdoor pollen category to fade as the weather cools. That pattern is why an autumn total is so often weed-led even when the headline number is low — tree and grass pollen have usually receded by then, leaving weed pollen, and on damp days mold, to make up most of what the index records. In the Plains and around the Great Lakes, ragweed is a familiar late-season plant of open ground, field edges and disturbed soil, which is why it so often leads inland autumn readings.
To see whether today’s pollen level holds, check the 5-day Harrisburg pollen forecast below — it is currently holding, with Saturday the highest day in the window.
This is the pollen count Harrisburg residents check each morning, built from the day’s tree, grass, weed and mold readings.
What is the Harrisburg pollen count today?
The Harrisburg 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 Harrisburg: this page is updated every morning with the day’s modelled reading.
Harrisburg allergies today
Harrisburg 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 Harrisburg allergies, this is the number that answers them — one daily index built from today’s tree, grass, weed and mold readings for Harrisburg.
Allergies in Harrisburg follow the Illinois 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 Harrisburg 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 Harrisburg allergy forecast: today reads 21 (Low), and the day-by-day outlook shows whether Harrisburg 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 Harrisburg today records is this same combined reading — tree, grass, weed and mold in one index.
The Harrisburg allergy count today is 21 (Low) — the same Total Pollen Index as the pollen count above, in one combined reading.
Pollen count today Harrisburg: the 5-day forecast
| Day | Total Pollen Index | Band |
|---|---|---|
| Saturday, November 7 | 21 | Low |
| Sunday, November 8 | 21 | Low |
| Monday, November 9 | 21 | Low |
| Tuesday, November 10 | 21 | Low |
| Wednesday, November 11 | 14 | Low |
Pollen Atlas forecasts Harrisburg’s pollen count to peak on Saturday at 21 (Low) over the next 5 days.
Pollen by type in Harrisburg
What is driving Harrisburg’s pollen today
The shape of today’s 21 (Low) is set by weed pollen at 27 (Low on its own scale) — about 91% of the four category readings added together, 25 points clear of the next category, grass pollen at 2. 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 Illinois 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 Harrisburg, so the drivers have to be read from the category split above. The Illinois guide’s account of Illinois names the classic tree, grass and ragweed sequence at full strength, with mold as a Chicago co-headliner — 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 14 to 21, never changing band. Today’s 21 sits 1 point above the window’s average of 19.6 — a moving window, worth reading day by day rather than from the average.
Plants affecting Harrisburg now
Detailed plant-by-plant readings for Harrisburg 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 2 (Low).
Weed pollen is one of the categories with a non-zero reading today, at 27 (Low).
In the Midwest & Great Lakes pattern, the plants that typically shape this city’s year are spring trees, late-spring and summer grasses, and late-summer and autumn ragweed — 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.
Harrisburg pollen through the year
Chapter by chapter, the Harrisburg pollen year runs like this:
- Trees run from March into May, later near the big lakes.
- Grasses hold from May through July.
- Ragweed builds from mid-August, peaks in September, and ends at the first frost.
- Mold builds through the humid summer and fills the gaps between chapters.
The Illinois allergy season guide names the classic tree, grass and ragweed sequence at full strength, with mold as a Chicago co-headliner. Lake Michigan delays spring flowering near the shore, so downstate Illinois often runs two to three weeks ahead of Chicago in spring — and behind it at the fall frost. The season typically starts in March in the south of the state and April in the Chicago area.
November falls between the main chapters of the Illinois 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 8 months of the Illinois year, March to October — a compressed season, which is why its chapters arrive in quick succession. The full calendar is set out in the Illinois allergy season guide.
How to read this index
Pollen Atlas reports the Harrisburg 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 even in a month when Harrisburg, IL pollen is usually more active. 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.
Harrisburg in today’s national picture
At 21 (Low), Harrisburg ranks joint 46929th of the 90896 cities Pollen Atlas tracks today — in the middle of the national table. The highest reading in the country today is Beja, Portugal at 52, and the lowest is Los Ángeles de San Rafael, Spain at 5. The whole table spans 47 points today — a wide-open day, when the top and bottom of the table are effectively in different seasons.
Around Harrisburg: Muddy, IL (3 miles away) reads 26 (Low); Carrier Mills, IL (6 miles away) reads 25 (Low); Raleigh, IL (6 miles away) reads 26 (Low). Harrisburg reads 5 points lower than its nearest tracked neighbour today. Across Illinois’s 1456 tracked cities, today runs from 12 in Hamburg to 41 in Elburn.
Pollen totals are population numbers; symptoms are personal. The same reading can leave one Harrisburg resident untouched and floor another, depending on which pollens they are sensitised to. If this pattern finds you every season, allergists in Harrisburg, IL 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.
Harrisburg in its local area
Across Illinois’s 1456 tracked cities, Harrisburg ranks joint 1307th today.
Like every Pollen Atlas city page, the Harrisburg, IL pollen count is refreshed each morning.
Nearby cities
- Muddy pollen count (3 miles away)
- Carrier Mills pollen count (6 miles away)
- Raleigh pollen count (6 miles away)
- Eldorado pollen count (8 miles away)
- Galatia pollen count (8 miles away)
- Equality pollen count (11 miles away)
From Pollen Atlas News
See how Harrisburg ranks in today's pollen count rankings — the worst cities for allergies today
Pollen indexes: a modelled pollen risk index computed by Pollen Atlas from open weather, vegetation and phenology data, calibrated against CDC/NAB season data. Plant detail: Google Pollen API. Index values are modelled, not measured counts. Sources: CDC/NAB; USA-NPN; GBIF (CC BY); ESA WorldCover (CC BY 4.0).