Oak Pollen: Season, Cities and Why It Hits So Hard

If spring allergies have a heavyweight champion in the eastern half of the United States, oak pollen is it. Oak pollen pours off one of the most common tree groups in the country — street trees, park trees, forest trees, and the live oaks that shade whole neighbourhoods in the South — and for a few intense weeks each spring it can dominate the Tree Index in city after city. People who sail through elm and maple season often meet their match in the oaks.

Key takeaways

• Oak pollen is one of the most common spring tree pollens in the eastern United States, pouring off street, park, and forest oaks for a few intense weeks each spring.
• Texas A&M AgriLife Extension notes that oaks typically flower and produce their pollen in March and April, and that the volume of spent catkins collecting on lawns and streets is a visible gauge of how much pollination is happening.
• Oak season slides north with spring: it peaks in late March to early April in Texas and along the Gulf Coast, in April across the Southeast, and in late April through May in the Northeast and Upper Midwest.
• On Pollen Atlas, oak is tracked as part of the daily Tree Index (0–100) on every city page, with per-plant detail showing when oak itself is driving the reading.

What oak pollen comes from

Oaks are members of the genus Quercus, a large group of trees and shrubs found across the United States, from the live oaks of the Gulf Coast to the red and white oaks of eastern forests and the bur and post oaks of the plains. That breadth is the first reason oak matters so much: there are oaks, in serious numbers, in almost every region east of the Rockies and in parts of the West as well.

Catkins: where the pollen comes from

Oaks are wind-pollinated, and the pollen comes from catkins — the long, hanging, tassel-like clusters that appear as the leaves emerge. Texas A&M AgriLife Extension horticulturists describe the pattern plainly: oaks typically flower and produce their pollen in March and April, the wind spreads it onto windshields and into noses, and the volume of spent catkins collecting on lawns and streets is a good visible gauge of how much pollination is happening. When the sidewalks fill with those brown-green tassels, the season is not coming. It is here.

A single neighbourhood can hold several oak species that flower in sequence, which stretches one tree's brief flowering into a neighbourhood season of several weeks.

When oak pollen season runs, region by region

Oak season is a spring event everywhere, but its calendar slides with latitude:

The southern benchmark: San Antonio

San Antonio's oak season is a useful southern benchmark: local reporting there puts the peak in late March and early April, with the season usually ending by early May — right as mountain cedar finishes, making oak the second act of the Texas spring. The wider southern pattern matches: LSU AgCenter's spring pollen overview describes spring pollination beginning in early March and running through April and into May, with oaks — especially live oaks — among the main culprits. In Atlanta, Georgia, Raleigh, North Carolina, and Charlotte, North Carolina, oak is a central character in the famous spring coating of yellow-green dust, sharing the stage with pine — though, as our pine pollen guide explains, the pine dust you see is not necessarily the pollen doing the damage.

Weather in the previous year can load the dice. Texas A&M AgriLife experts have noted seasons where generous fall rain followed by a long stretch of winter cold set oaks up for significantly higher-than-average pollen production the following spring. Two springs are never identical, which is why the calendar gives you the window and the daily index gives you the day.

How oak pollen behaves

Built for wind, driven by weather

Oak pollen grains are built for wind travel — small and light enough to ride spring breezes well beyond the tree that made them — and oaks produce them in volume. The practical consequences:

• It is a canopy problem, not a yard problem. Avoiding your own oak does little when the whole street, park, and woodland edge are flowering at once.
• Peaks are weather-driven. Warm, dry, breezy days in the flowering window produce the big counts; rain temporarily washes the air and knocks counts down.
• It overlaps its relatives. Oaks sit in the order Fagales, the same broad group as birch, alder, and hazel, and cross-reactivity among these related tree pollens is documented — the birch allergen literature lists oak among the pollens that can cross-react with birch sensitivity. Someone who reacts in birch country in May and oak country in April may be meeting cousins, not strangers. This is general information only; only testing can sort out an individual's sensitivities.

The Asthma and Allergy Foundation of America likewise lists oak among the trees that cause the most spring symptoms, and notes that tree pollen is light enough for wind to carry for miles. Oak also shares its weeks with a crowd. In Dallas, Texas and Austin, Texas, oak follows cedar and runs alongside ash, pecan, and the first grasses. A high Tree Index day in April is often a blend — oak is simply the biggest contributor in most eastern and southern cities.

Oak pollen and the yellow-green film

Every spring, photos circulate of cars, porches, and pond surfaces coated in yellow-green dust across the South, and oak takes much of the blame — sometimes fairly, sometimes not. Oak pollen does contribute to that film, and the fallen catkins are unmistakably oak. But pine, which releases at the same time in the Southeast, contributes a large share of the visible dust while being a far weaker allergen.

Visible, and genuinely allergenic

Visibility and allergenicity are different axes, and oak sits high on both: it is seen and it matters. Our companion piece on birch pollen covers the northern tree that plays a similar double role.

Tracking oak pollen on Pollen Atlas

On Pollen Atlas, oak is tracked as part of the daily Tree Index on every city page — scored 0 to 100, Low from 0 to 33, Moderate from 34 to 66, and High from 67 to 100 — with per-plant detail that lets you see when oak itself is driving the reading. In peak weeks, check:

• Your city page each morning (start with Atlanta, Raleigh, Charlotte, Dallas, or Austin)
• The national city rankings to watch the oak wave move north week by week — the rankings map the season's migration better than any calendar
• The wider tree pollen season guide for how oak fits the full spring sequence

If spring symptoms hit you hard every year and you want to know whether oak is your specific trigger, an allergist can test for it — search the Pollen Atlas Find an Allergist directory by city and specialty. This article is general information about a pollen pattern, not medical advice.

Frequently Asked Questions

When does oak pollen peak?

Oak pollen peaks in spring, earliest in the South. Texas and the Gulf Coast typically peak in late March to early April, the Southeast in April, and the Northeast and Upper Midwest in late April through May.

Why does oak pollen hit so hard?

Oak pollen hits hard because oaks are everywhere and they are wind-pollinated. Whole streets, parks, and woodland edges flower at once, and several species in one neighbourhood can flower in sequence, stretching the season over several weeks.

Is the yellow-green dust on my car oak pollen?

Not entirely — oak pollen does contribute to that spring film, and fallen oak catkins are unmistakably oak. Pine releasing at the same time contributes a large share of the visible dust, even though pine is a far weaker allergen.

How can I check the oak pollen count for my city?

Pollen Atlas city pages publish a daily Tree Index with per-plant detail, so you can see when oak itself is driving the reading. Checking each morning during your region's oak window is the simplest way to follow the season day by day.

Oak season is short, intense, and entirely predictable in shape if not in daily detail. Know your region's window, watch the Tree Index through it, and the weeks that used to ambush you become weeks you can plan around.

Before the catkins fall, check the oak outlook for your city — see today's Tree Index and 5-day forecast, free, on PollenAtlas.com.

Sources cited in this post: Texas A&M AgriLife Extension (oak flowering, March–April, catkin volume as a pollination gauge; prior-year rain and cold effects on pollen production); KSAT San Antonio (oak season peak late March–early April, ending early May, 2025); LSU AgCenter (spring pollination beginning in early March and running through April into May, with oaks among the main culprits); birch allergen fact-sheet literature (oak listed among pollens cross-reactive with birch).