Asthma During the Summer

Heat, Humidity, and Allergens Can Worsen Symptoms

If you have asthma, summer can be a difficult season. Heat and humidity can affect your airways and trigger wheezing, shortness of breath, and other symptoms, increasing the likelihood of asthma attacks. This is regardless of the type of asthma you have, but if you happen to have allergic asthma, you may find managing your asthma to be especially challenging, as allergens such as pollen and mold are particularly plentiful in hot, humid weather. The same is true if you have exercise-induced asthma and tend to be more active outdoors during the summer.

How to Manage Asthma During the Summer

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Causes of Summer Asthma Symptoms

Although asthma symptoms tend to be most common in fall and winter, summer presents some unique risks.

Heat: The mere fact that you have asthma means your lungs are especially sensitive to extreme heat, and so breathing in hot air can aggravate your airways and trigger symptoms. What's more, if you become dehydrated, you will naturally breathe more rapidly than normal, which also can play a role in setting off symptoms.

Humidity: Humid air is heavy air, and so it's harder to breathe, especially when it's also hot. In addition, moist air traps lung irritants such as pollen, mold, and, indoors, dust mites.

Ozone: Ozone is a product of atmospheric chemicals and sunlight. Although somewhat controversial, some researchers believe this pollutant can exacerbate asthma, based on studies that show lung function worsens in the days after ozone levels peak, affecting people with asthma and even people without it.

Summer Allergens: If you have allergic asthma and are triggered by certain allergens that are especially prevalent in June, July, and August, it stands to reason you're more likely to have asthma attacks during those months.

  • 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)

Smoke: From a small campfire to a 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.

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Managing Summer Asthma

If you have a history of worsened asthma in the summer, work with your asthma healthcare provider to devise a seasonal action plan, which may include incorporating additional medications and/or lifestyle measures into your overall management measures.

It will be key to head into summer with your asthma well under control. It is not 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 healthcare provider. These steps may include taking a daily asthma controller medication to prevent asthma symptoms and rescue medications to treat acute symptoms.

If you have allergic asthma that is triggered by a known allergen, the most important thing you can do is try to avoid that allergen as best you can. When you can't, your healthcare provider may enhance your medication regimen to include:

  • Oral antihistamines: Antihistamines work by altering the immune system's overreaction to allergens and prevent bronchoconstriction (narrowing of the airways) 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. Ask your healthcare provider or pharmacist how often you can safely use a nasal spray.
  • Nasal steroid sprays or nasal cromolyn sodium: These over-the-counter nasal sprays, such as Flonase (fluticason) are some of the most effective medicines, and because they act only where needed, they're also some of the safest.
  • Saline irrigation: This involves rinsing the nasal cavities with salt water to flush out pollen and other allergens. One way to do this with a simple device called a neti pot, which you can purchase in your local pharmacy.


Steering clear of allergens altogether may be difficult, especially if you enjoy being outside in the warm weather. In addition to 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.
  • 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), limit outdoor activities as much as possible.
  • Shower after outdoor activities. Wash off pollen or other irritants you may have tracked indoors.
  • Don't let dust accumulate in your home. Pollen 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.
  • Consider immunotherapy (allergy shots). The National Institutes of Health recommends subcutaneous immunotherapy (SCIT) for some people over 5 who have allergic asthma. Ask your healthcare provider if allergy shots might be appropriate for you.
7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  3. Goodman JE, Zu K, Loftus CT, et al. Short-term ozone exposure and asthma severity: Weight-of-evidence analysisEnviron Res. 2018;160:391-397. doi:10.1016/j.envres.2017.10.018

  4. United States Environmental Protection Agency. Health effects of ozone in patients with asthma and other chronic respiratory disease.

  5. Cascio WE. Wildland fire smoke and human healthSci Total Environ. 2018;624:586-595. doi:10.1016/j.scitotenv.2017.12.086

  6. Reid CE, Maestas MM. Wildfire smoke exposure under climate change: impact on respiratory health of affected communitiesCurr Opin Pulm Med. 2019;25(2):179-187. doi:10.1097/MCP.0000000000000552

  7. Cloutier MM, Baptist AP, Blake KV, et al. 2020 focused updates to the asthma management guidelines: A report from the national asthma education and prevention program coordinating committee expert panel working group. Journal of Allergy and Clinical Immunology. 2020;146(6):1217-1270. doi:10.1016/j.jaci.2020.10.003

By Pat Bass, MD
Dr. Bass is a board-certified internist, pediatrician, and a Fellow of the American Academy of Pediatrics and the American College of Physicians.