Allergy season timing varies widely by location, weather, and specific pollen triggers. In the Northern Hemisphere, it generally kicks off in late winter or early spring and rolls through fall, with no single "start date" since multiple waves hit throughout the year.

Spring Kickoff

Spring allergies often launch tree pollen season, which can begin as early as February in warmer southern U.S. regions like the Southeast or Southern California.

In cooler spots like the Northeast, Midwest, or Illinois, expect a March start as oaks, maples, birch, and cedars bloom through June.

A recent allergist guide notes this early onset ties to milder winters, pushing pollen counts up sooner amid climate shifts.

Regional Breakdown

Allergy starts shift dramatically by where you live—here's a quick regional guide based on expert insights:

Region| Typical Spring Start| Key Triggers
---|---|---
Southeast/South| January–February| Trees (oak, birch); early grass 15
Northeast/Midwest| March–April| Trees, then grass by May 1
West Coast| February–ongoing| Extended mix of trees, grass 1
Southwest/California| February–year-round| Trees, weeds; heat limits peaks 5
Desert areas (e.g., Palm Springs)| Early spring| Shorter bursts due to aridity 5

This table pulls from 2025-updated sources, highlighting how coastal mildness stretches seasons.

Summer and Beyond

Grass pollen dominates May through July , peaking in many areas and blending into ragweed for summer sufferers.

Fall weeds like ragweed hit August to November , with mold spiking in humid zones. Winter often means indoor allergens, but outdoor pollen can linger year-round in places like California.

Harvard Health emphasizes prepping ahead, as rainy springs boost mold alongside pollen.

Trending Factors in 2026

With it being early March 2026, warmer trends are extending seasons—some forum chatter and recent posts note earlier starts this year due to mild winters.

Multi-viewpoint: Allergists say climate change is shifting peaks earlier (e.g., February now common vs. traditional March), while patients on health sites report year-round symptoms for 2/3 of spring allergy folks.

One 2025 California update predicts ongoing year-round risk in the south from prolonged pollen.

Preparation Tips

Beat the sneezes with these steps, drawn from allergist advice:

  1. Track local pollen counts via apps—forecasts blend weather data for daily heads-ups.
  1. Start meds early (antihistamines, nasal sprays) 2–4 weeks before your region's typical onset.
  1. Limit exposure : Stay indoors peak hours (10 a.m.–4 p.m.), use HEPA filters, shower post-outdoors.
  2. Test for triggers : See an allergist for personalized shots if OTC fails.

Imagine gearing up like a weather prepper—stock antihistamines by late January if you're in the South, and you've got the edge on that February bloom. TL;DR at bottom: Allergy season often starts February–March for spring trees, but check your zip code—it's hyper-local and trending earlier.

Information gathered from public forums or data available on the internet and portrayed here.