Don’t let weather wreck your summer travel. Here’s how to plan.

Practice everyday thunderstorm safety

Summertime is prime season for thunderstorms and flooding across much of the nation.

Most cellphones will automatically alert you if certain types of severe weather are imminent: a tornado, a severe thunderstorm producing winds of at least 80 mph or hail at least 2.75 inches in diameter, or flash flooding that is significantly life-threatening and could cause substantial damage. But even the weakest of thunderstorms can produce a potentially deadly lightning strike.

Lightning has killed an average of 22 people per year over the past 10 years, according to the National Lightning Safety Council, with the most deaths typically occurring during the summer months of June, July and August.

While there are apps that can help you keep track of lightning — WeatherBug, for example, will show you the distance to the closest lightning strike in the past 30 minutes — the safest strategy is to follow the National Weather Service’s advice: “When thunder roars, go indoors,” and stay there for 30 minutes after the last sound of thunder.

Strong thunderstorm winds and flooding are particularly dangerous for those camping in an RV, because they are not anchored to the ground. Experts warn that RVs should not be used as shelter during severe weather and urge people to never drive an RV in high winds. Instead, campers should seek shelter in a sturdy building and have multiple ways of accessing weather information, with one option being a battery-powered NOAA weather radio.

Don’t dismiss hurricane season, even with El Niño

Hurricane season is always a wild card for those planning summer vacations to Florida, the Gulf Coast, the Eastern Seaboard or the Caribbean. There’s not much use in avoiding one area more so than any other, since a storm can strike pretty much any location anytime from June to October. Historically, the most number of tropical storms and hurricanes occur during a period from late August through mid-September.

One factor that could influence the upcoming hurricane season is the expected El Niño conditions, the warming of the eastern tropical Pacific Ocean that influences weather patterns around the globe. El Niño may already be developing, and forecasters anticipate it could become a moderate to strong El Niño during the summer.

El Niño tends to reduce the amount of hurricane activity in the Atlantic Basin because of increased wind shear, or variation, which stunts the growth of tropical cyclones. However, travelers shouldn’t necessarily count on that being the case.

“El Nino typically reduces Atlantic hurricane activity via increases in vertical wind shear. However, Atlantic is extremely warm right now, potentially mitigating typical shear impacts,” tweeted Colorado State University hurricane researcher Philip Klotzbach.

If you have plans to visit a hurricane-prone area, make sure to follow official forecasts from the National Hurricane Center. When looking at a forecast, it’s important to understand that a storm’s track and landfall location can end up anywhere within the cone of uncertainty and sometimes outside of it. Dangerous hazards such as storm surge can extend well beyond the cone.

Keep track of harmful algal blooms

California’s spectacular super bloom should be winding down across most of the state by summer. It’s another kind of bloom — the harmful algal bloom sometimes known as “red tide” — that you should keep in mind if you have summer plans in Florida or the Gulf Coast. The blooms can also occur in the Great Lakes — the National Oceanic and Atmospheric Administration expects a “moderate harmful algal bloom” this summer on Lake Erie — and other bodies of water in every state.

Red tide is caused by explosive growth of certain types of microscopic algae that produce harmful chemicals. A single bloom can kill thousands of fish and many other animals. Swimming in or around red tide can cause skin irritation, rashes, burning and sore eyes, coughing, wheezing and shortness of breath. Symptoms can be worse for people with asthma, emphysema or bronchitis.

The blooms typically occur during the fall, but can take place earlier or later, such as the red tide observed in March along Florida’s southwest coast. They can last a few weeks, months and sometimes over a year, but typically only affect small portions of the coast for short periods of time.

The specific location and severity of an algal bloom can’t be reliably forecast more than a few days ahead of time. Once a bloom is detected, though, NOAA provides a forecast of respiratory irritation at individual beaches in Florida and Texas for the next 24 hours. NOAA’s Harmful Algal Bloom Monitoring System provides real-time monitoring of coastal and lake regions across the country.

“Red tide conditions can change quickly,” said Carly Jones, a public information specialist at the Florida Fish and Wildlife Conservation Commission, in an email. “The Florida Department of Health advises people with severe or chronic respiratory conditions, such as emphysema or asthma, to avoid red tide areas … even if you are not prone to respiratory issues, you should be careful.”

Take the threat of rip currents seriously

Beachgoers must also be vigilant for hazards in the water. The death of a 21-year old from New Jersey earlier this month was a tragic reminder of this. The man had been swimming at Ocean City, Md., when he was reported missing on May 6. His body washed ashore the next day.

In a Facebook post shortly after he disappeared, the Ocean City Police Department said that “rip current conditions currently exist” and noted that lifeguards were not on duty.

Rip currents are strong, narrow currents of water that flow away from the shoreline and can suddenly sweep swimmers out to sea. Predicting where and when a rip current will form is difficult because of a number of ocean and weather factors. The Weather Service cautions that “rip currents often form on calm, sunny days.”

“Never swim if the beach patrol is not on duty,” said Butch Arbin, captain of the Ocean City Beach Patrol, in an email. “If you do see someone in trouble when lifeguards are not on duty, call 911. But do not try and make the rescue, because that often leads to also becoming a victim.”

Before you go into the water, it’s a good idea to check the Weather Service’s rip current forecasts for beach locations, which are informed by a new rip current forecast model. If you are caught in a rip current, the Weather Service says not to swim directly back to shore against the current, which is often too strong for even the best of swimmers. Rather, you should swim parallel to the shore until you are out of the current, which is typically no wider than about 50 to 100 feet.

Get to know a different kind of heat index

As climate change makes heat waves hotter, longer and more frequent, more people are turning to a different kind of heat index as a more useful measure of heat stress: the wet bulb globe temperature (WBGT).

The heat index that most people are familiar with takes into account only the temperature and humidity, and assumes you are in the shade. That calculation should suffice if you are just taking a short walk or going about routine daily activities. But those who work or exercise outside, and anyone who coaches or manages outdoor athletic activities, may want to better understand the wet bulb measurement.

The WBGT is measured and predicted assuming direct sunlight and also factors in wind speed, sun angle and cloud cover. It has been around since the 1950s but has received more attention in recent years with the increase in extreme heat.

The Weather Service provides WBGT forecasts here. Below is a general summary of the effects and recommended actions, including how often to take a break and how much water to drink. Impacts and actions adjusted for different regions of the country can be found here.