Ah, the heart of summer. With the July 4 weekend approaching fast, it's time to hit the open road or simply go outside and enjoy the dog days in your own back yard.  We've collected some apps that can help keep your summertime adventures rolling no matter what your style. Feel free to mix and match. Just keep that smartphone out of the sun.

For the road warrior: There's something magical about a good road trip, but highway travels can also be a logistical nightmare if you have a low tolerance for getting lost. Some would say that's the point, of course, but it's harder to make that argument when you're out of gas and nowhere near a gas station.

Gas Buddy is a staple on best travel app lists, and that's because it works really well. As you can probably guess from the name, this app acts as your guide to finding gas stations near you and at a price you're willing to pay. Prices are user-submitted, which means you can submit them, too, and tend to be fairly reliable. It's certainly worth a download if you're the kind of driver who likes to go until you're running on fumes, or just like to grab the best deal. Free, for iOS and Android.

iExit is designed to prevent some of the most infuriating road trip moments — "Which exit!?" "Uh, the one we just passed." — by letting you know what's coming up just off the highway ahead of you. You can find gas (and some, but not all, prices), food, lodging, campgrounds, ATMs and more in an exit-by-exit guide. The app can help you by reading your location if you let it, or you can search by highway if you know where you're going. This app costs $0.99 for iOS and is free for Android.

Also try: Roadtrippers, TV Foodmaps and Waze.

For the staycationer: Vacation is a state of mind. If you have a pool, a park or even just a really great tree near you, you don't have to go very far at all to enjoy the lazy days of summer. As an extra tip, keep your phone in an empty cooler to keep it out of the sun but not in a place where you'll forget it. Drop it in a plastic bag first, though, to avoid damaged from lingering melted ice cubes.

Field Trip is an app that educates you about cool things around you that you may not know about. Ever wonder who's memorialized in that statue in the park or longed for the story behind that stately building down the street? The app gives you a write-up of notable places around you (assuming there are notable places around you) that make for fascinating reading. It's a nice way to get a new look at your old stomping grounds. Free, for iOS and Android.

Weber makes a few apps that can be your ultimate grilling companions. They have an excellent repository of recipes for the grill that range from your standard burgers to vegetarian options and grilled fruit desserts. Weber Grills on the iPhone or Weber on Android also have built-in timers to help make sure that everything is cooked to perfection. And if you need a little remedial grilling instruction, you can find that too. Free, for iOS and Android.

Also try: Wolfram Sun Exposure or TV Guide — for those really hot days.

For the jet-setter: Traveling farther afield also means having to prepare a different toolkit. Here are a couple of apps to help you if you find yourself in far-off lands. Foreign language-learning apps are also good to download before you go — top-rated apps include Duolingo, Babbel and Memrise, depending on the language you want to learn — and supplement that trusty phrasebook.

Private Internet Access is an effective, simple and relatively cheap VPN (virtual private network) — a service that can give you a level of protection against attacks on sketchy WiFi networks. It can also change your location, which comes in handy if you need to access the U.S. version of a site while abroad. Private Internet Access's network is easy to flip on and off and lets users choose how web traffic should be routed — the app can also choose for you. This is the service I use personally. But because VPNs tend to require payment, you should shop around and see what works best for you — other notable VPNs include F-Secure Freedome, HotSpot Shield and Norton WiFi Privacy. Private Internet Access's service is $40 per year.

Postagram is the tool for people who always say they'll send a postcard and never do. You can send a custom card to anyone starting at 99 cents, using photos from your own gallery or snapped live with your camera. Write a little message, fill in the address and — bam! — a thoughtful postcard and no need to track down a postbox. While you do lose out on the charm of foreign stamps and postmarks, you end up with a more personalized postcard. Free to download, for iOS and Android.

For the explorer: Getting off the grid may not necessarily sound compatible with downloading new apps, but your smartphone can be a valuable tool even when you're trying to unplug. One tip, though: If you're going to have lousy cell service anyway, it's a good idea to head into airplane mode while you're hiking to save battery.

AllTrails may not really have guides to all of the trails, but it sure makes a good effort. The app boasts more than 50,000 hiking and biking trails across the United States. You can sift results by difficulty. It also lets you filter trails to see which are wheelchair accessible, kid-friendly or good for pets. A pro version, which costs $30 per year, lets you access maps offline as well, which can be good when you've succeeded in getting away from it all. Free, for iOS and Android.

Recreation.gov is an iPhone app made in partnership with the federal government for finding campsites to book at federal parks. True, it's not much more than a search tool — actually booking will take you to the mobile web. But it's a handy tool for planning, particularly if you're looking to book something in a short time period and are less picky about where you stay. Be aware that this is just for federal parks, so you'll have to look elsewhere for state or private campgrounds. Free, for iOS.