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Summer is here at last, and that means it’s thunderstorm season. Every pilot knows that airplanes and thunderstorms don’t go together. Unfortunately, weather can be unpredictable, especially in the summer months. It’s not unusual for perfectly sunny skies to develop dark and ominous clouds throughout the day.

Here are a few reminders to avoid getting caught in a thunderstorm:

Know before you go

As with any flight, obtain a preflight briefing. Always check the convective forecasts and flight radar reports before flying. While en route, don’t hesitate to check a weather app or tune in to the Flight Watch frequency (122.0 MHz) for relevant pilot reports. It’s also a good idea to plan your flight early in the morning when convection is at its lowest.

See and avoid

For a thunderstorm to develop, three conditions need to be present: moisture, unstable air, and a lifting force. To get an indication of these factors, look to the clouds. Cumulonimbus clouds — those with extensive vertical development — serve as a warning sign for an impending storm. Well-developed cumulonimbus clouds have a distinctive flat top, called an anvil. Almost every type of flying hazard is contained in these clouds, so steer clear if you see them.

Don’t try to “thread the needle” between storms

Even if you notice holes between developing thunderstorms, don’t try to weave your way through them. Gaps of clear air between storms can close in quickly, trapping you in a dangerous situation. The FAA recommends staying at least 20 nautical miles away from the edge of a thunderstorm cell to avoid encountering potential hazards.

Never try to fly below or above thunderstorms

Attempting to fly under a line of thunderstorms may subject your airplane to destructive hazards, including heavy rain, hail, wind shear, turbulence, lightning, and microbursts. Trying to outclimb storm clouds isn’t an option, either. Thunderstorms can reach heights of 50,000 to 60,000 feet, far beyond the capabilities of light aircraft.

What to do if a storm is unavoidable

Ideally, you can alter your route or initiate a go-around and land before getting dangerously close to a thunderstorm. If you find yourself inadvertently flying into a storm, the FAA recommends staying the course. The idea is that making a 180-degree turn inside a storm could take longer than flying straight through, although this doesn’t necessarily cover every situation.

If you’re stuck inside a storm, you should declare an emergency with ATC to receive assistance. When flying through a storm, keep your eyes on your instruments and trust what they’re telling you. Turn up the cockpit lighting to prevent temporary blindness from lightning. Focus on keeping the aircraft upright. Few lucky pilots have survived flying through thunderstorms, so the best advice is to avoid close encounters in the first place.

For more summer flying tips, watch AOPA’s latest Seasons of Safety video: 105 Days of Safe Summer Flying.