Not every asthma trigger is tied to the calendar, but each season brings its own set of unique circumstances that are important to know. We talked to Paul Williams, M.D., of the Northwest Asthma & Allergy Center in Seattle, about how to keep your symptoms in check.

Winter Woes: Cold air and stuffy rooms. Spending lots of time cooped up inside your house can expose you to indoor irritants like dust and debris circulating from home heating systems (particularly fireplaces). Have a professional check and clean your system, ideally before you first turn it on for the season.

If cold air is one of your triggers, Dr. Williams suggests using your short-acting bronchodilator before going out. Also, cover your mouth and nose with a scarf or muffler to help warm the air before it enters your lungs.

Spring Alerts: Pollen, seasonal allergies, and spring cleaning. Warmer temperatures mean grass, trees, and weeds are coming to life. And that means pollen is in the air. Morning is peak time for pollen counts, so consider moving your favorite outdoor activities to later in the day. If you suspect (or know) allergies might be triggering an asthma flare-up, talk to your doctor about getting tested and taking an allergy medicine to prevent reactions.

Another thing to keep in mind this time of year is the common ritual of spring cleaning. Everyone wants a clean home—just be sure to use products that are free of harsh chemicals and take steps to avoid inhaling fumes.

Summer Trials: Air quality, hot temps, and pets. Keep summer vacation from turning into a miserable memory by planning a getaway in a spot with good air quality. The Environmental Protection Agency’s AirNow air quality website provides real-time nationwide air quality data. High temps and humidity are other common triggers. When you’re planning your itinerary, try to plan outdoor activities for later in the day, when pollen counts tend to dip. And when you’re booking hotel rooms, ask for a pet-free room. Staying with friends and family who have pets? Politely tell them about your condition and ask if they can vacuum before your arrival and set aside a pet-free sleeping space for the length of your stay.

Fall Adversaries: Cold and flu season kicks in. “Colds are the number one cause of asthma flare-ups,” says Dr. Williams. Check with your doctor to find out what steps you can take to prevent respiratory illnesses and review your sick-day plan. For example, you may need to increase the amount of controller medication at the start of a cold. Get a flu shot and ask your doctor if you’re due for the pneumonia vaccine. Also remember to wash your hands thoroughly and frequently—it’s one of the best defenses—and do your best to keep your distance from sick people.