A day at the pool or beach, hitting the trails for a hike, a cookout at the park — warm weather and outdoor activities go hand in hand.

But summertime fun can quickly turn sour if you don't take certain precautions. Here are five summertime hazards to avoid so you can stay healthy in the months ahead.

1. Heat-related illnesses

"Becoming familiar with the warning signs of heat-related illness could prevent a hot-weather problem from escalating into a crisis," says Dr. Hina Tahir, a primary care physician at Houston Methodist.

Heat cramps are painful abdominal spasms and cramps in the major muscles, such as the legs and abdomen. Rest, cooling down and drinking plenty of water usually help cramps subside. (Related: Does Pickle Juice Help With Muscle Cramps?)

Heat exhaustion presents an array of symptoms — fever, fainting, rapid pulse, low blood pressure, clammy skin, ashen skin tone and nausea. "Move indoors or to a shady spot, immediately lie down, prop up your feet, loosen tight clothes and drink cool water or sports beverages," recommends Dr. Tahir.

Heat stroke can be life-threatening and requires immediate medical help. Symptoms include not only those associated with heat exhaustion, but also rapid pulse and breathing, delirium, fainting and lack of perspiration to cool the body.

To prevent a heat emergency:

• Avoid the sun from late morning until 4 p.m.
• Limit vigorous exercise to early mornings or evenings
• Dress in light-colored, loose-fitting clothes
• Drink plenty of water
• Avoid caffeine and alcohol

Some individuals — including older adults and people with certain heart problems or on medications that increase heat sensitivity — are more vulnerable to the heat and will need to take even more precautions.

2. Sunburn

Prolonged, unprotected sun exposure can lead to sunburn, wrinkles and, at worst, skin cancer.

Sunscreen is one of the best tools to protect skin from the sun's harmful UV rays, so you'll need to wear it whenever you plan to be out in the sun. (Related: Is Spray Sunscreen Actually Effective?)

To prevent sunburn and stay safe in the sun:

• Buy a quality sunscreen rated at least SPF 30 and apply it liberally to all exposed skin
• Reapply sunscreen at least every two hours — or more frequently if needed per the product's label
• Wear sunglasses that block both UVA and UVB ultraviolet rays
• Wear a wide-brimmed hat and sun-protective clothing
• Take extra precaution if you're on a medication that makes your skin more sensitive to the sun

3. Waterborne illness

You can become sick if you swallow, have contact with or breathe in mists of water contaminated with germs in swimming pools, water parks and rivers or lakes.

"Common waterborne illnesses include diarrhea and gastrointestinal upset, ear infections, respiratory infections and skin rashes," Dr. Tahir adds.

To avoid water-borne illness:

• Avoid swallowing water, being sure to remind kids of this regularly
• Shower before and after swimming to wash off germs
• Keep ears dry with earplugs or a bathing cap while in the water
• Dry ears thoroughly with a towel or hairdryer after swimming

(Related: 10 Tips for Keeping Your Family Safe at the Pool)

4. Food poisoning

Picnics and cookouts can be a hot spot for food poisoning, especially in hot weather since heat makes perishable foods spoil faster. Not having access to a full kitchen can present complications, too.

When outdoors in the heat, keep perishable food safe by:

• Washing your hands before handling food, using disposable wipes if soap and water aren't available
• Keeping raw food separate from cooked food
• Covering your food, since flies can spread Salmonella
• Thoroughly cooking meat, poultry and fish
• Keeping hot food warm and eating it immediately
• Keeping cold food cool and returning it to the ice chest after serving
• Discarding food that's been left out after one hour
• Making sure food is served on clean plates and eaten with clean flatware

(Related: Medium Rare Burger: How Pink Is Too Pink When It Comes to Ground Beef?)

5. Insect stings

Bee, wasp or hornet stings can cause a medical emergency if you're allergic to their venom. (Related: When to Worry About an Insect Sting)

Most people, however, only experience sharp pain that goes away after a few minutes. Still, it's important to care for a sting.

To treat a sting properly:

• Promptly remove the stinger using a flat edge, such as a credit card, to scrape it away from the welt
• Apply ice to reduce pain from swelling
• Spread cortisone ointment over the sting to reduce skin irritation from itching