Asthma During the Summer

Heat, humidity, and increased allergens can worsen symptoms

For some, the summer can complicate asthma management and make asthma attacks more likely. Heat and humidity can affect your airways and make breathing harder, increasing symptoms—regardless of what type of asthma you have. Those with allergic asthma triggered by pollen or fungi have the added challenge of allergen levels being high in the summer, making flare-ups more likely.

This doesn't mean you can't enjoy sunny days and warm weather if you have asthma. However, it does mean it's worth working with your doctor to identify summertime triggers and determine the best ways to manage your asthma with the seasons.

Thermometer against a sunny sky

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Weather and Atmospheric Conditions

While studies show peaks in asthma symptoms during the fall, and exercise-induced asthma is more prevalent in colder months, summer presents some unique risks for anyone who is prone to asthma symptoms and attacks.

Asthma symptoms include:


The high temperatures of summer alone can make your asthma worse in several ways.

  • Having asthma makes your lungs more sensitive to extreme heat.
  • Breathing in hot air can aggravate your airways and trigger symptoms.
  • Heat can dehydrate you as well, which can cause rapid breathing.

All of those factors, alone or in combination, can lead to increased symptoms and asthma attacks. That's especially true if you're exercising outside or taking part in outdoor sports.


Living in a humid area affects asthma, as well. Heavier air is harder to breathe, especially when it's also hot.

In addition, moist air traps all kinds of things that can irritate your airways, including mold and dust mites.

While these things are worse for people with allergies, you don't have to have allergies for your lungs to be irritated by them. And when you have asthma, any irritation to the airways can trigger symptoms.


Another pollutant that can be elevated in humid air is ozone—a product of atmospheric chemicals and sunlight.

High ozone levels are believed to be a common asthma trigger. While not all researchers agree about ozone's impact, some studies show that lung function worsens in the days after ozone levels peak, affecting people with asthma and even people without it.

According to the Environmental Protection Agency (EPA), when ozone levels are high, people with asthma may have:

  • Decreased lung function
  • Increased respiratory symptoms
  • Increased medication usage
  • More frequent asthma attacks
  • Increased need for health-care services

With sunlight more prevalent in the summer, ozone pollution can be a constant problem throughout the summer months, especially in hot, humid areas.


Thunderstorms are more common in the summer and can be an asthma trigger. The storms are caused by instability in the air that results from contact between warm air near the ground and cold air above it.

During and after thunderstorms, at any time of year, emergency rooms see an increase in asthma-related visits. One study shows that the number of admissions for asthma rose 15% during thunderstorms.

Experts don't yet fully understand the reason for this connection, but they suspect thunderstorms can rupture, release, and spread pollen grains that many people are allergic to.

However, rapid changes in temperature, which are common during thunderstorms, may trigger asthma unrelated to allergies. Storm-related asthma attacks have also been reported in people with no previous diagnoses of asthma or allergies.

Summer Allergens and Irritants

If you have allergic asthma, you're more likely to have asthma attacks in the summer because certain allergens are more prevalent during June, July, and August. Especially common are allergic asthma symptoms triggered by:

  • Pollen: This is the fine, powdery material plants release during fertilization, which occurs mostly in warmer months. Summer weather promotes the release of pollen, which then travels through the air and is inhaled.
  • Mold: Many types of mold spores thrive in heat and humidity. In summer months, they grow in soil, seeds, grass, and dead leaves or vegetation. They're also more likely to grow indoors during these months, especially in areas of the home where moisture and temperatures are high, like your bathroom.

If you're allergic to pollen and/or mold, your immune system sees them as harmful and releases chemicals called histamines that are supposed to defend your body.

The defense system, in this case, does more harm than good. Even though there's no actual threat, the body will try to flush out the allergens that get in and prevent more from invading. It does this by:

  • Making your nose run and eyes water
  • Making you sneeze and cough
  • Narrowing your airways (bronchonstriction)
  • Producing a mucus barrier

This leads to inflammation and clogging of the respiratory system, which makes breathing difficult and can trigger asthma attacks.

Allergen Level Peaks

Your risk of asthma attacks increases when your allergy triggers are high, so it's good to be aware of when they're elevated.

  • March through June: Tree pollen high
  • May through early June: Grass pollen high
  • June: Outdoor mold spores peak, then decrease after the first frost
  • August through the first frost: Weed pollen high (daily peaks around noon)


From a small campfire to raging wildfires, you're more likely to be exposed to smoke in the summer months. Smoke carries fine particulate matter that can get into your airways and have a major impact on asthma.

Wildfire smoke is a growing health concern in many areas as fire seasons become worse over time. That smoke is hard on everyone's lung health, but multiple studies have demonstrated an especially negative impact on people with asthma.


To determine whether your asthma is aggravated by summer weather conditions, your doctor may have you see an allergist, who will perform a series of allergy tests. During a skin test, they place common allergens on or just under the top layer of your skin to see if you have a response.

You may also undergo blood work to see how your immune system reacts when you're exposed to possible allergens.

If your symptoms aren't directly related to an allergen, your doctor may rely on your self-reports of your symptoms to determine whether a seasonal trigger (like heat or thunderstorms) is causing the attack.

In both cases, your doctor will likely perform pulmonary function testing.


If you have a history of worsened asthma in the summer, talk to your asthma doctor about a seasonal action plan, which may include additional medications or lifestyle changes, depending on your asthma type and triggers.

You'll want to go into summer knowing your asthma is well-controlled. It's not considered well-controlled if:

  • You use a rescue inhaler more than twice a week
  • Asthma symptoms interrupt sleep more than twice a month
  • You need a new rescue inhaler more than twice a year

Be sure to follow your asthma action plan, try to avoid triggers, and stick to the asthma medication regimen prescribed by your doctor. These steps may include taking a daily asthma controller medication to prevent asthma symptoms and rescue medications to treat acute symptoms.

The best treatment for allergic asthma involves managing allergic reactions that can trigger an asthma attack. Talk with your doctor about whether the following treatment options could help you get allergies under control.

  • Oral antihistamines: Antihistamines work on histamines to alter your body's overreaction to allergens and stop bronchoconstriction and mucus production. An oral antihistamine can take up to two weeks to reach full effectiveness, so you should start taking it well before your allergens peak.
  • Nasal decongestant sprays: These relieve nasal symptoms on a short-term basis, but they cannot be safely used throughout the summer. If used too often, they can actually make nasal symptoms worse.
  • Nasal steroid sprays or nasal cromolyn sodium: These over-the-counter nasal sprays, such as Flonase, are some of the most effective medicines, and because they act only where needed, they're also some of the safest.
  • Saline rinse: For a more "natural" approach, you can use a saline nasal rinse/irrigation. These wash out pollen, other allergens, and mucus from the nasal passages by flushing them with salt water (saline).

You may want to talk with your doctor about immunotherapy or allergy shots to help with allergy and asthma relief. These treatments can make your body less sensitive to the pollens and mold causing your symptoms. Newer forms of this treatment include a pill that can be placed under the tongue.

Symptoms may change as the summer progresses and different allergens become more or less common in the air. Monitor your asthma to see if new situations trigger a reaction and discuss these with your doctor.


The best way to deal with asthma is to prevent an attack. Aside from following your prescribed treatment plan, this may involve taking some special precautions in the summertime:

  • Check pollen counts for your area: You can get this information from local weather forecasts, on TV or online, from weather or pollen-count smartphone apps, or from the National Allergy Bureau's website. Remember that pollen can be an airway irritant even if you're not allergic.
  • Stay indoors on bad days: During extreme heat and humidity, high pollen or wildfire smoke days, thunderstorm warnings, ozone alert days (and a few days afterward), you may need to limit your outdoor activities. Having indoor exercise equipment can help you stay healthy during these times.
  • Shower after outdoor activities: Wash off pollen or other irritants you may have tracked indoors.
  • Avoid dust accumulation: Pollen in particular can get intermingled with dust and lie around for long periods. Keep windows closed, vacuum often, and dust (perhaps while wearing a mask) to avoid inhaling these allergens/irritants.
  • Use a dehumidifier and air conditioner: Reducing the humidity in the air and keeping the temperature cool (but not freezing cold) can make it easier to breathe in general as well as help prevent the growth of mold.

A Word From Verywell

A good plan can keep your asthma in check so you don't feel like you have to stay inside all summer to feel well. Work with your doctor, be proactive, and monitor your symptoms and triggers so you can manage your condition and enjoy the warmer weather months.

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