Summer Asthma and Warm Weather. How it Affects Your Asthma.

People often ask: “Does summer make asthma worse?” or “Why is my asthma worse in the summer?”

Some people with asthma may experience fewer symptoms and flare-ups during the summer. Others may experience an increase in asthma symptoms leading to full-blown summer asthma attacks.

Hot and humid weather and exposure to pollens, mold spores and air pollution could cause asthma symptoms to flare. Warm weather activities such as playing sports, exercising and camping could also lead to increased respiratory problems.

Let’s explore some causes of summer asthma, identify common triggers and learn summer asthma tips to avoid flare-ups.

Does asthma flare up in summer?

For some people with seasonal asthma, summer is when asthma symptoms tend to improve. In many areas of the country there are fewer triggers, such as respiratory viruses and cold, dry air. More time is spent outdoors so there is less exposure to indoor allergens.

For others, summer heat and allergies affect asthma. Heat and humidity of summer weather can make breathing difficult for people with asthma. Summer months also increase exposure to different asthma triggers such as tree, grass or ragweed pollen, thunderstorms, campfires and air pollution.

If you’re concerned about having a summertime asthma attack, talk with your doctor about adjusting your Asthma Action Plan during summer months.

Enjoy your summer, but be aware that there may be increased health issues for people with asthma.

What are the causes of summer asthma?

Hot weather aggravates asthma. Heat and humid conditions can lead to constriction and narrowing of the airways. This makes breathing difficult for people with asthma.

Heat also increases the risk of air pollution. It traps ozone and particulate matter from cars, trucks and other sources. When in the air, these can be easily inhaled and cause asthma symptoms.

Also during the summer, the air can become stagnant. This can trap pollens, dust, mold and pollutants. These are potential triggers of allergic asthma.

What is usually the best temperature for someone with asthma? It’s usually between 68 to 71 degrees F with low humidity.

What are summer asthma symptoms?

Asthma symptoms in the summer are the same as during other times of the year.

  • Coughing: it’s often worse at night or early morning. Coughing can be dry or mucus-filled.
  • Wheezing: this is a whistling or squeaky sound when you breathe out. Sometimes wheezing is easily heard; other times you need a stethoscope.
  • Chest tightness: this may feel like something is squeezing or sitting on your chest.
  • Shortness of breath: you may feel like you can’t catch your breath or breathe deeply enough. You may feel as though you are out of shape and constantly tired.

Severe symptoms can lead to a summertime asthma attack. This occurs when your airways are very inflamed and swollen. It can narrow your breathing tubes and make it harder to get air into and out of the lungs. An asthma attack is a life-threatening emergency and often requires medical care. Call 911 if you’re experiencing an asthma attack.

What are summer asthma triggers?

There are many potential asthma triggers. They can be present outdoors and indoors. Common summer asthma triggers include the following:

Heat-induced asthma and humidity

Breathing in hot air can trigger summer asthma symptoms. It can cause airways to tighten and narrow, making breathing more difficult.

Humid air is filled with moisture, which means it’s heavier air sometimes filled with allergens and irritants. This creates poor air quality and can cause asthma symptoms to flare.

Ozone and air pollution

When temperatures are high and air is stagnant, ozone and air pollution can rise to dangerous levels. This causes poor air quality. Prolonged exposure can cause respiratory problems for everyone, but especially for people with asthma. Ozone is the major component of smog.

Ozone is a chemical formed when emissions from motor vehicles, power plants and certain industries interact with sunlight. Increased levels of ozone can:

  • irritate your respiratory system
  • damage cells that line your lungs
  • reduce lung function
  • make your asthma symptoms worse

Pollen and mold spores

People with asthma who are allergic to pollen and mold spores could experience symptoms anytime when trees, grass and weed pollens (such as ragweed) are blooming. Tree, grass and weed pollens all are present at various times during the summer.

  • Tree pollen: February through June
  • Grass pollen: May to early July
  • Weed pollens (including ragweed): early August through first frost

Oak, elm, maple and birch are among the most common tree allergens in the United States. It often overlaps with the spread of grass pollen. Tree and grass pollens spread during dry, breezy conditions. There are many different kinds of grasses that produce pollen. The most common that can cause grass allergies are:

  • Bermuda grass
  • Kentucky bluegrass
  • Bahia grass
  • Fescue grass
  • Johnson grass
  • Timothy grass

Ragweed is a potent allergen. It thrives in warm temperatures, reduced humidity and breezy conditions.

Outdoor mold spores are fungi with seeds. When inhaled, they can cause allergy symptoms. Mold spores travel through the air, often at night in dry, foggy or windy weather conditions. They may also spread when it’s humid outside. Mold spores peak in June and linger through the summer. They decline at first frost.

Thunderstorm asthma

Thunderstorms can trigger asthma symptoms. Thunderstorm asthma occurs when there are high levels of grass pollen and mold spores in the air when a thunderstorm strikes. Heavy winds disperse tiny allergen particles into the air where they can be easily inhaled. This can inflame airways and lead to an asthma flare-up.

Thunderstorm asthma is rare but it can cause severe symptoms. Most people with asthma are not prepared for the burst of allergens and onset of symptoms.

For many people with asthma, sudden changes in weather combined with can cause symptoms. This includes not only thunderstorms but also increases or decreases in temperature and humidity. If you live in an area with unpredictable weather, be sure to keep your quick-relief inhaler (also referred to as rescue inhaler) with you at all times.

Sports and physical activity

With warm weather comes opportunity to play outside, whether it’s sports, hiking or riding a bike. About 90% of people with asthma can have exercise as a trigger for respiratory problems. When breathing heavily during physical activity outdoors, they may breathe in higher amounts of pollen or mold. There may be other environmental factors such as bad air quality that could lead to symptoms.

People with exercise-induced asthma (EIA) only experience asthma symptoms during or after exercise. It’s usually recommended people with EIA pre-treat with an albuterol inhaler 15-20 minutes before any exercise.

It is important for people with asthma to get exercise. There are many proven benefits of exercise for people with asthma. It can improve lung function and help you reduce or maintain weight. It is important to monitor asthma before, during and after exercise.

Swimming in chlorine pools

Swimming is often considered a safer activity for people with asthma. In fact, many Olympic swimmers have asthma. Swimming can help regulate breathing. Pools are usually a warm, humid environment that is conducive to healthy airflow.

Does chlorine aggravate asthma? Some swimmers with asthma may experience symptoms due to chlorine in pools. Chlorine can irritate the airways. Studies suggest chlorine may be more dangerous for people with asthma in indoor pools than outdoor pools.

Former Olympic swimmer Tom Dolan, who runs a swim school in Sterling, Virginia, says chlorine in pools is one of his asthma triggers. He says the first 5-7 inches off the water surface contain the most chlorine. It can be easily inhaled. Talk with your doctor about options, such as pre-treating with albuterol, if chlorine impacts your asthma.

Does swimming in saltwater aggravate asthma? No. Swimming in the ocean, for example, may be beneficial since there is obviously no chlorine.

Camping trips and campfires

Before you plan a camping trip, think about your asthma triggers and the time of year. If grass and tree pollen trigger your asthma, then it may be best to not go camping in June or early July. If ragweed pollen is your asthma trigger, then avoid camping in August and early September.

Be sure to clean out your tent before your camping trip to ensure you’re not bringing mold and mildew with you. This can trigger allergic asthma.

People with asthma should avoid campfires when possible. Smoke from campfires can irritate and inflame the airways. It could also possibly lead to an asthma attack. Since campfires are a tradition at most campgrounds, you may not be able to – or want to – avoid it. Try to sit far back from the campfire and out of the way of smoke. If wind blows smoke in your direction, switch places right away. Ask a friend to roast marshmallows for your s’more.


Wildfires are becoming increasingly common, especially in Western states. If you have asthma and live in an area impacted by a wildfire, breathing in the smoke could worsen your asthma. Wildfires cause lung irritation and inflammation when smoke is inhaled.

Even if you live far away from wildfires, you’re still at risk. Wildfire smoke can travel very long distances. People with asthma hundreds of miles away from a wildfire may experience breathing problems.


Fireworks tend to reduce overall air quality. They release smoke and particles that can irritate your airways and worsen asthma. Even short-term exposure to firework smoke and particles has been shown to make asthma worse. People with asthma should watch fireworks from a distance and avoid smoke. Keep your quick-relief inhaler with you in case symptoms arise.

Indoor allergies

Don’t forget about allergens inside your home. During the hot and humid months of summer, dust mites and mold – both common asthma triggers – can thrive.

You may want to wash your bedsheets and pillow cases in hot water a little more often in summer months to get rid of dust mites. Keep an eye out for mold in typically damp areas, such as the bathroom or basement.

Other allergens to watch for indoors are pet dander (if you have pets), cockroaches and mice.

Vacation travel

Many families travel in the summer. If you have asthma, it’s important to be prepared. Asthma symptoms can arise at any moment. This is especially true when you’re in an unfamiliar environment where you may be exposed to new triggers.

Schedule a checkup with your doctor to discuss travel plans and get prescription refills. Store medications in your asthma travel pack. If traveling by airplane, keep your asthma travel pack with you in your carry-on bag so it doesn’t get lost on the way to your destination. Check the Asthma and Allergy Forecast in the area you’re vacationing. Find allergy friendly hotels for overnight stays. Check out more travel planning tips to keep your asthma in check during vacation.

If you’re traveling somewhere that is high in altitude, keep in mind that there will likely be less oxygen than on sea level. This can bring on shortness of breath and possibly lead to asthma symptoms.

Trips to the beach are obviously common in summer. Are there other triggers at the beach that could cause an asthma attack? Apart from heat and humidity causing symptoms, the beach is mostly considered a safe place for fresh air and healthy breathing.

What helps asthma in hot weather?

Board-certified allergist William Berger, MD, past president of the American College of Allergy, Asthma & Immunology (ACAAI), offers these strategies for people with asthma. These strategies could help you avoid asthma attacks:

  • Stay inside as much as you can on hot, humid days. Keep windows closed.
  • Keep cool. Use a dehumidifier and air conditioning with clean filters. It’s best to use a High Efficiency Particulate Air filter, or HEPA filter.
  • Monitor your Asthma and Allergy Forecast daily. This predictive tool uses weather forecast info, seasonal plant growth, pollen levels and historical data to identify days when asthma and allergy triggers are likely to be present.
  • Check your local air quality index and pollen count before going outside. EPA issues state and local air quality forecasts.
  • Shower after outdoor activities to wash off any pollens collected on your skin or hair.
  • Stay hydrated. Water helps thin any mucus in your lungs and airways. It can also cool your body off.
  • Keep taking your daily asthma medication to help keep your airways clear and symptoms under control.
  • Talk with your allergist or healthcare provider about adjusting your Asthma Action Plan or treatment plan during summer days.

Why is it important to keep taking asthma medications during the summer?

Asthma doesn’t take a hiatus during the summer. So why do some asthma patients? Studies show that patients who cut back or stop taking daily asthma medication during the summer – without consulting their doctor – are at greater risk of serious asthma symptoms in the fall.

For schoolchildren and even adults, maintaining your usual asthma treatment plan in the summer is one of the best ways to avoid the September Asthma Peak. This is the annual spike in asthma flares and asthma-related hospitalizations among children. Healthcare providers can even predict the point the spike starts: shortly after Labor Day.

Ragweed and mold spores soar in the fall and can trigger asthma. And when the school year begins, children with asthma are exposed to more respiratory illnesses.

Staying on medication schedule is a critical part of an Asthma Action Plan. The Asthma Action Plan gives specific instructions for managing and asthma treatment. Talk with your healthcare provider about adjusting your Asthma Action Plan if you experience increased coughing, wheezing and shortness of breath during summer.