It’s July, which means summer is in full swing in Cambridge. And with longer days and balmy temperatures, you might be looking for ways to get outside and into a pool, the beach, or under the shade of an elm tree. Or maybe you just want a fun place to spend a few hours (complete with air conditioning!). Here are some of Harvard Law School’s favorite cool-down spots you can get to from another one of Boston’s best amenities — the MBTA, or the T. 

Revere Beach 

Also known as America’s first public beach, at more than three miles long, Revere Beach is a fun spot to meet up with friends, take a dip in the ocean, and enjoy the festive atmosphere. Time your visit right and you might catch the annual sandcastle sculpting contest, typically held in July. Architecture or history buffs (or those who need a little shade) will also appreciate the Victorian pavilions and other original features. Sample classic Boston fare at Kelly’s, located just across the street. Roast beef on the beach? It’s less strange than you might think. 

From Harvard Square: Take the Red Line toward Braintree or Ashmont. Exit at Downtown Crossing. From there, walk a few blocks north up Washington Street to the Blue Line. Take the Blue Line north to the Revere Beach or Wonderland stations. 

Arnold Arboretum 

Designed by Frederick Law Olmsted, the landscape architect behind New York’s Central Park and Boston’s Emerald Necklace, Harvard’s Arnold Arboretum, a 281- acre preserve, celebrated its 150th birthday this year. The Arboretum’s rolling hills, ponds, and paths contain an impressive collection of plant and tree specimens from around the world. There are plenty of nooks and crannies to explore, including a bonsai garden, and something is always blooming. Take one of many guided tours of the park, catch an art show – or just bring your walking shoes and explore on your own. 

From Harvard Square: Take the Red Line to the Downtown Crossing stop, then transfer to the Orange Line toward Forest Hills. Get off at the Forest Hills stop, follow signs inside the station toward Arnold Arboretum, and walk a few minutes up Arborway to the Forest Hills entrance. 

Castle Island 

Enjoy the beautiful ocean views (and breeze) with a trip to South Boston’s Castle Island. First, walk or cycle the waterfront trail around the park, then explore Fort Independence, a site that has been occupied since at least 1634, though the existing structure dates to the mid-19th century. Once you’ve worked up a sweat, take a swim in the cool, clean waters of Pleasure Bay or at one of the numerous other beaches nearby. Feeling famished? Make a pit stop at Sullivan’s, a seaside institution on Castle Island, for a wax-wrapped pack of fish and chips and a raspberry lime rickey. Don’t forget the ice cream cone for dessert. 

From Harvard Square: Take the Red Line toward Braintree or Ashmont and get off at the Andrew station. If you’re feeling adventurous (or up for a long walk), you can stroll from the station to the shore via Preble Street and walk along the beach east to the park. Or you can take 10 bus from Andrew station to the P St. & E. 2nd St. stop. 

Charles River  

In its 80-mile meander from Hopkinton, Massachusetts to its outlet on the Atlantic Ocean, the beautiful Charles River offers many opportunities for recreation and contemplation on both the Cambridge and Boston sides. If you’re feeling adventurous, rent a canoe or kayak in Kendall Square for a round trip cruise up and down the river. Or stroll the Esplanade, making your way to Herter Park, where you can catch a concert at the amphitheater and grab a cold beverage at the beer garden. 

From Harvard Square: This one is easy! You can walk to the Charles River right from Harvard’s campus. Take the Red Line to Kendall Square for the kayaking experience, or to the Charles/MGH station to walk the Esplanade. 

Singing Beach, Manchester-by-the-Sea 

Named for the musical quality of the sand when walked upon, Singing Beach is a pristine, half-mile wide expanse that features a 1920s bathhouse and a refreshment stand. Although there is a $10 day use fee, Singing Beach is quieter and less busy than Revere, and its cold, clear waters are sure to rejuvenate you. When you’re done playing in the waves, you can also walk around Manchester-by-the-Sea, a historic resort town that is much more than the namesake movie. 

From Harvard Square: Take the Red Line to Downtown Crossing, then transfer to the Orange Line going to Oak Grove. Get off the Orange Line at North Station and take the Newburyport/Rockport Commuter Rail Line to the Manchester-by-the-Sea stop.   

Isabella Stewart Gardner Museum 

Feeling too overheated to be outside? Enjoy the air-conditioned bliss at one of Boston’s quirkiest, and most interesting institutions, instead. The Isabella Stewart Gardner Museum — which was also the site of one of history’s most notorious art heists — contains an impressive collection of Asian, European, and American works. Gardner’s bequest required that nothing be sold from her collection or moved from where she originally placed it in the building, so you can enjoy the museum in much the same way as its first guests in 1903 did — aside from a few empty frames where the stolen works once hung. 

From Harvard Square: Take the Red Line toward Braintree/Ashmont and transfer to the Green Line (E) at Park Street toward Heath Street. Get off at the Longwood Medical Area stop.