Find A DoctorAllergy seasons
Many people assume allergy season starts in the spring. That’s when the frost recedes and flowers start to bloom. But take a closer look at your regional allergy calendar in the klarify app and you’ll see that’s not the case.
When the allergy seasons happen and how they affect you will depend a lot on where you live and the weather. Both have a big influence on pollen and mold, another seasonal allergy trigger.
When are the allergy seasons?
The four allergy seasons span the whole year. Pollen dominates three of them and can be a factor in the fourth. The margins where one season tips into another get a bit blurry. You can check out the pollen calendar for your region in our free allergy app.
Pollen production may start earlier after mild winter temperatures. Meanwhile a wet spring can cause rapid plant growth and an increase in mold. Some trees may start to pollinate in the coldest months. But the first hard frost will kill off many other plants that contribute to seasonal allergies. Outdoor molds commonly cause summer and fall allergies but most become inactive during winter. In the South grass pollen exposure may cause allergy symptoms year-round.
But that’s not the end of the story. Winter may be the quietest of the allergy seasons for outdoor allergens but it’s when allergies move indoors. Molds thrive in a damp bathroom, kitchen or basement. Central heating can blow dust mite allergens around your home. Pet dander is another indoor trigger so spending quality time with your dog on the sofa could get you sneezing.
What are the main triggers in the different allergy seasons?
Airborne allergens that trigger seasonal allergic rhinitis are what you need to watch out for. A plant releases pollen into the air to fertilize other plants of the same species. On windy days the fine dust can travel for hundreds of miles from its origin. Mold spores can be even tinier than pollen grains and they too travel in the wind.
The first clue that you’ve breathed in the particles is when you get hay fever symptoms like sneezing or a runny nose.
Allergy seasons: Spring
- In the Northeast tree pollens start between mid-February (which is winter, strictly speaking) and the beginning of April. Grass pollen comes in two waves: the first is at the start of May.
- For the West many tree pollens like birch start around March, but some species pollenate from the previous allergy season. Grass pollen starts in mid-March and begins to peak in April.
- In the Midwest tree pollens start in the previous season and are followed by grass pollen at the beginning of April.
- Across to South Central US, tree pollens like birch are at their peak. Grass pollen is high too. Both started at the end of the previous allergy season.
- Southeast tree pollens like birch are at their highest in early spring, having started in the previous season. Grass pollen starts at the beginning of April and reaches its peak in late spring.
Allergy seasons: Summer
- Tree pollens have either finished or are low by the summer months in the Northeast.
- In the West the first wave of grass pollen is at its peak through May and most of June before ending in mid-July. The second wave begins in mid-August. Weed pollen begins shortly before.
- Tree pollens have either finished or are finishing by early summer in the Midwest. Grass pollen continues throughout the season, peaking for a second time towards late summer. Weed pollen begins in early August.
- South Central US mostly sees tree pollens reduce in the early part of the summer. But some species last the whole season. Grass pollen is at its peak at the start of June before reducing. It has a second peak towards the end of July that lasts the remainder of the season. Ragweed pollen starts in August.
- Most tree pollens have ended or reduce in early summer in the Southeast. Certain species last the whole season or peak again towards the end of August. The grass pollen high lasts just into June and the season ends in early July. Ragweed pollen starts towards the end of August.
Allergy seasons: Fall
- Grass pollen is at its second peak from the beginning of September in the Northeast. It finishes towards the end of October. Ragweed pollen levels are still at their peak for the first half of September, before finishing towards the end of the month.
- In the West certain tree pollen (elm) has a second wave that peaks throughout September before ending in early October. Grass pollen also has its second peak through September and into October before ending in mid-November. Ragweed pollen peaks through September before reducing, but still lasting into the next allergy season.
- Tree pollen (elm) has a second short peak at the beginning of September in the Midwest, before reducing and ending at the end of the month.
- In South Central US tree pollen (elm) has a second peak that lasts the duration of the season. Other tree pollens (alder) are low before ending completely by mid-September. Grass pollen also has its second peak through September and into October before reducing and ending by early November. Ragweed pollen is also at its peak at the start of September and into October before reducing and ending towards the end of the month.
- Tree pollen (elm) has its second peak from the end of August into September, then finishes by the end of the month in the Southeast. Other tree pollens (alder) are low before ending completely by mid-September. Ragweed pollen is present throughout September, peaking mid-month, before finishing by mid-October.
Allergy seasons calendar: Winter
- Northeast tree pollens like elm, juniper and maple start in February and peak in the next season, spring.
- Tree pollens like alder, juniper and ash last through the winter in the West, hitting highs in January or February. Ragweed pollen can also be an issue in the first half of December.
- The Midwest has tree pollen like elm, maple and oak from February into the next allergy season.
- Tree pollens like elm and juniper have highs and lows throughout this season in South Central US. All types are active by the end of February into the next season. Grass pollen also starts towards the end of February.
- In the Southeast tree pollens like juniper, alder and elm start from January onwards.
What are the symptoms
of seasonal allergies?
Other symptoms tied to the allergy seasons
Mild allergic reactions in your mouth, lips or throat when you eat could be seasonal allergies. Cross-reactions happen when your immune system thinks proteins in certain fruit and veg are the same as your allergens. It’s called oral allergy syndrome (OAS).
For example, if your mouth tingles in spring after eating an apple it could be a birch pollen allergy playing up. Or if you get a local reaction after eating mushrooms, spinach or yeast in fall it could be a mold allergy. It may bother you more when you are already experiencing symptoms of seasonal allergies.
Allergy seasons and the weather
Day-to-day weather factors can affect your allergies. Long spells without rain may make trees release more pollen. And the fine dust can travel further through the air on dry days.
Light rain can be helpful as moisture weighs the grains down. But heavy rain can break up and scatter clumps of pollen. So allergy symptoms may be worse during a storm, for example. Rain and humidity can also make mold counts go up. So does fog and dew.
Weather shifts that affect the allergy seasons can also affect your allergies. For example, a warm wet winter may lead to more severe spring allergies if the plants bloom early.
Are allergy seasons getting longer?
Climate change is pushing temperatures up and this is already affecting the allergy seasons. A study of 11 locations in North America found that 10 had a longer ragweed season than 20 years ago. For example, Minneapolis gained an extra 18 days.
It’s not just ragweed either. A recent three-decade study found allergy seasons for tree, grass and weed pollen have lengthened by 20 days or more. And pollen concentrations have increased by 21% during this time.
Extreme weather events can also influence allergy seasons and they’re likely to become more common. Mold spores can multiply indoors after flooding. Hospitals in New Orleans saw a rise in allergy symptoms after Hurricane Katrina. People with hay fever fared differently in the allergy seasons after hurricanes Florence and Michael. Pollen levels in the areas affected were much lower the following spring.
Allergy medicines:
What are the options?
Preparing for the allergy seasons
The key is to get to know your allergy seasons. Then you can take steps to avoid your trigger. Our app lets you check daily pollen levels, the weather and air quality for your area. There’s also a pollen forecast on our website.
Practical steps include keeping windows and doors closed when pollen or mold counts are up. Air-conditioning can help you to remain comfortable – just don’t let the filter go moldy. Wear a sunhat, wrap-around sunglasses and face mask when you go out. Change your clothes when you get home, dry them indoors and wash your hair before bed.
If you use symptom-relieving medication, take it before you leave home or even before your allergy season starts. We’ll look at this next.
Allergy seasons: Some treatment options
Antihistamines and corticosteroids can help ease symptoms like nasal congestion, sneezing or watery eyes. These allergy medications are available in different forms so ask your pharmacist or healthcare provider for advice.
They may suggest starting with antihistamine or a corticosteroid nasal spray from two weeks before you’re likely to get hay fever. Decongestants can also unblock a stuffy nose but shouldn’t be used for more than a few days. These can all help keep symptoms in check.
Can you change how allergy seasons affect you?
There’s no cure for allergy. But you might be able to influence your allergy calendar. Allergy immunotherapy is a way of retraining your immune system. It’s a long-term treatment and involves repeated small doses of your trigger via injections (allergy shots) or tablets.
There’s immunotherapy for tree, grass and weed pollen, and some types of mold (and many other allergens, of course). Treatment takes several years and the aim is that allergy seasons have less effect on your life. Your healthcare provider can tell you if immunotherapy right for you.