Every February I get the same question from other parents in our neighborhood: "When does this end?" They mean the endless sneezing, the pillow covered in yellow pine dust, the kid who can't sleep through the night. I tell them the truth — tree pollen season doesn't end so much as hand off. One species peaks, the next ramps up, and by the time oak finally drops in May, the grass is already starting.
2026 is shaping up to be another above-average tree pollen year. Mild winters across the Mountain West, an early warm-up in the Southeast, and the now-familiar pattern of pollen seasons starting earlier and lasting longer than they did a generation ago. If you're trying to plan around it — for trips, kids' outdoor activities, or just figuring out when you can finally open the windows again — this is the calendar I built for my own family.
TL;DR — Tree pollen season at a glance
- Cedar & juniper kicks off in December–March, hitting Texas Hill Country hardest.
- Maple & elm bridge late winter into early spring (February–April) across the Northeast and Midwest.
- Oak, birch, and pine overlap from March–May — the worst stretch for most of the U.S. east of the Rockies.
- By late May / early June tree pollen tapers and grass season takes over.
- For decisions today, the calendar is a starting point — pair it with live data for your city.
Why 2026 is different (and similar) to last year
If 2026 feels worse than you remember from 10 years ago, that isn't in your head. The NIH and PNAS have both published research showing North American pollen seasons are starting roughly 20 days earlier than they did in 1990, with peak concentrations up an average of 21%. The mechanism is straightforward: warmer winters end earlier, frost-free days arrive sooner, and CO₂-rich air helps plants produce more pollen per flower.
For 2026 specifically, the AAFA 2026 Allergy Capitals report highlighted three regional shifts worth knowing about:
- Mountain West dominates. Boise, Provo, Ogden, and Salt Lake City are all top-15 nationally, driven by cedar/juniper season starting in December and a long dry spring concentrating pollen.
- Florida joins the top 20. Lakeland made its debut this year as pine pollen season extends further into spring.
- Southern Plains stay punishing. Tulsa (#3) and Wichita (#6) — oak and elm-heavy regions — keep climbing.
For our deeper read on AAFA's ranking, see AAFA's 2026 Worst Allergy Cities.
The six major tree pollens (and where each is worst)
Not all tree pollens are created equal. Here are the six types most likely to wreck your spring, listed in roughly the order they appear:
🌲 Cedar & juniper · December – March
Famous for "Cedar Fever" in Texas Hill Country — the condition is so widely recognized it has its own name and its own tourist-warning advisories. Mountain cedar (technically a juniper) releases massive pollen plumes in late December through February, often visible as a yellow-orange cloud rolling off hillsides. Symptoms can rival the flu: fever, body aches, severe congestion.
Worst hit: Austin, San Antonio, and the broader Texas Hill Country. The Mountain West (juniper, not cedar) lights up at the same time — Salt Lake City, Boise, Colorado Springs.
🍁 Maple · February – April
Maple is one of the earliest true spring trees, often flowering before any leaves appear. The classic red-flowered maples (silver, red, sugar) are heavy pollen producers that signal the end of winter for Midwest and Northeast allergy sufferers. Most people don't realize they have a maple allergy until they read the species breakdown — they assume it's "spring allergies in general."
Worst hit: Chicago, Minneapolis, Detroit, Boston, Cleveland, and the rest of the Great Lakes / New England maple belt.
🌳 Oak · March – May
For most of the Eastern and Southern U.S., oak is tree pollen season. A single oak tree can release tens of millions of pollen grains per day during peak. Unlike pine (which you can actually see as yellow dust on cars), oak pollen is smaller and nearly invisible — but its grains lodge deeper in the airways and produce some of the worst symptoms of any tree species. Many people who blame the visible "yellow stuff" for their misery are actually reacting to the oak pollen they can't see.
Worst hit: Atlanta, Raleigh, Charlotte, Nashville, Houston, and most of the Southeast and mid-Atlantic. Atlanta in particular is famous for hitting four-digit pollen counts during peak oak weeks.
🌿 Birch · April – May
Birch pollen is concentrated in the Pacific Northwest and Northern New England, but its allergens cross-react with apples, peaches, carrots, and almonds — which is why so many people develop sudden "food allergies" in spring (Oral Allergy Syndrome). Birch is a relatively short, intense season — about three weeks of misery, then done.
Worst hit: Seattle, Portland, Spokane, Boston, Burlington, and the inland Northeast.
🌲 Pine · April – June
Pine produces the most visible pollen — those yellow clouds drifting through the air, the powder coating outdoor furniture — but its grains are so large they rarely cause classic IgE-mediated allergic reactions. The irritation pine causes is usually mechanical (irritated airways from sheer volume) plus the non-pine pollens it carries.
Worst hit: The entire Southeast, especially Atlanta, Houston, Jacksonville, and Charlotte. Coastal regions get pine pollen drift even from forests miles inland.
🌳 Mulberry & ash · April – May
Often overlooked because they're common urban trees rather than forest species. Mulberry produces enormous pollen volumes and is especially aggressive in the desert Southwest and Southern California. Ash is widespread but milder unless you're directly downwind. Both contribute to the "why is everyone sneezing in mid-April?" chorus in cities you wouldn't expect.
Worst hit: Los Angeles, Phoenix, Tulsa, Dallas, and most large cities with mature urban tree canopies.
Month-by-month tree pollen calendar
Here's how the season actually unfolds across the U.S. — when each species ramps up, where to watch first, and what to brace for next.
January — Cedar season ignites
Cedar/juniper is the headliner. Texas Hill Country experiences its peak misery ("Cedar Fever"), and Mountain West juniper joins late in the month. Most of the rest of the country is quiet — a brief reprieve before maple kicks off.
Watch: Austin, Salt Lake City, Boise
February — Maple wakes up the East
Maple flowering begins in mid-Atlantic and Southeast. Cedar still raging in Texas. The first wave of "why am I sneezing already?" questions hits parent group chats. Pre-season antihistamines start to make sense if your kid's history shows a bad March.
March — Things get serious
Oak begins in the Deep South. Maple and elm peak across the Midwest and Northeast. Birch starts in the Pacific Northwest. This is when most parents realize they need a plan, not just a box of Zyrtec.
April — Peak chaos for most of the U.S.
Oak, pine, birch, and mulberry all overlap. Pollen counts hit their annual peaks across the Southeast and mid-Atlantic. Yellow pine dust everywhere. This is the worst month for kids east of the Rockies. Open windows are a mistake; HEPA filters earn their keep.
Watch: Atlanta, Raleigh, Charlotte, Houston, Nashville, Los Angeles
May — Tree pollen tapers, grass takes over
Oak and pine wind down by mid-month in the South, late month in the North. Birch ends in the Pacific Northwest. But grass season is already ramping up — the handoff is brutal for anyone allergic to both. Northeast cities get a few good weeks before grass hits hard in late May.
Watch: New York, Boston, Portland, Minneapolis
June — Mostly grass, finally
Tree pollen is essentially done across the Lower 48 (except for late pine in coastal Southeast). The Pacific Northwest gets a real break in early-to-mid June before grass dominates. If your kid only reacts to tree pollens, this is when they get their life back.
Watch: most cities are calmer for trees — start tracking grass instead.
July – November — Tree pollen quiet, but ragweed waits
Tree pollen stays low through summer. Mid-August onward, ragweed and other weed pollens take over (a separate guide territory). Cedar starts whispering again by late November in Texas. The cycle restarts.
What to actually do about it
Knowing the calendar isn't the same as having a plan. Here's the playbook I run for my own kids — pulled from two years of trial-and-error, plus our pediatrician's patience:
1. Start meds two weeks before your peak
Antihistamines work better as prevention than rescue. If your kid's history shows oak as the trigger, don't wait for Atlanta to hit four-digit oak counts in mid-April. Start in late March. Talk to your pediatrician about timing — they'll know what's standard for your area.
2. Track your city, not the national average
AAFA rankings tell you which cities are worst on average. They don't tell you whether today is bad in your specific ZIP code. After a hard rain, even Atlanta can have a low pollen morning. Before a windy dry afternoon, even "mild" cities can spike. PollenTracker refreshes every 4 hours for 800+ cities — see how I actually use it for my kids.
3. Run HEPA in the bedroom
The single highest-impact piece of equipment is a HEPA air purifier in your kid's bedroom. It catches the pollen that comes in on clothes, hair, and pets, and it works overnight when you can't actively manage exposure. True HEPA filtration captures 99.97% of particles 0.3 microns and larger — pollen is 10–100 microns, so it's caught easily.
4. Shower and change before bed
Pollen sticks to hair, eyebrows, and clothes. If your kid played outside, the pillow becomes a pollen reservoir. A 5-minute shower and clean pajamas is the cheapest, most effective intervention you can do — and it's the one most parents skip.
5. Watch the wind, not just the count
High pollen + low wind = pollen stays put (mostly safe to be outside). Moderate pollen + high wind = pollen everywhere (avoid). We don't look at raw numbers anymore; we look at the forecast's YES / CAUTION / NO output, which factors in wind.
The longer view: pollen seasons are changing
Two data points stay with me from the climate research:
- 20 days earlier. The pollen season starts almost three weeks earlier than it did when most of today's parents were kids. February allergies are the new normal.
- 21% higher concentrations. Even if the season length didn't change, the volume per day is up — driven by warmer growing seasons and elevated CO₂.
For parents, this means yesterday's rules of thumb ("wait for April", "Atlanta is the worst") are slowly breaking. The cities at the top of AAFA's list shift every year, and species that used to peak in May now peak in April. Tracking your specific city's real-time data is no longer just nice-to-have — it's the only thing that keeps up.
FAQ
When does tree pollen season actually start?
It depends on what you mean by "start." Cedar/juniper kicks off in late December in Texas. Maple and elm follow in February across the East. The mainstream "tree pollen season" most people experience — oak, birch, pine — runs from roughly mid-March to late May, peaking in April for most of the country.
Does rain wash pollen away?
Mostly yes. A good steady rain pulls airborne pollen down and dampens grass and tree surfaces. The 24-48 hours after a heavy rain are usually the safest outdoor time during peak season. But— short, hard storms can also break pollen grains apart into smaller fragments that can trigger asthma even more aggressively. Watch the pattern, not just the precipitation.
Is tree pollen worse in the morning or evening?
Mornings, especially 5 AM – 10 AM. Most trees release pollen at dawn when temperatures rise; counts peak mid-morning and ease through the afternoon. Late evening (after 8 PM) is often the safest outdoor window in spring. This pattern reverses on windy days — wind keeps pollen aloft all day.
Can my kid develop a tree pollen allergy as an adult?
Yes, and it's common. Many adults move to a new region and develop sensitivity to local species (oak in the Southeast, juniper in Texas) within 2–3 years of exposure. It's not your imagination if you didn't have allergies in your old city.
How long does a typical tree pollen season last?
For an individual species, 4–8 weeks. For the overall "tree season" encompassing all species, roughly January through early June for most of the country (peaking March–May). Cedar, oak, and pine each have their own 3–6 week peaks within that window.
Get tomorrow's tree pollen forecast for your city
The calendar above tells you when to brace yourself. For deciding whether your kid can go to the playground this afternoon, you need today's data — not a seasonal average. PollenTracker covers 800+ U.S. and U.K. cities, refreshes every 4 hours, and gives you a clear YES / CAUTION / NO answer. No login, no ads, no spam.
— Peter, dad of two allergic kids, builder of PollenTracker. Updated for the 2026 season; revised annually.