WHEN THE DAYS GET LONG, CAMBRIDGE HEATS UP AND...

The prospect of heat, humidity, poor air quality and crowds of tourists is enough to send anyone scampering for the shoreline.

But hazy, stifling days are not all that a summer in Cambridge has to offer.

While conventional wisdom holds that any sane person, given the chance, would depart Cambridge as soon as possible for Cape Cod or the Maine Coast or Martha's Vineyard or Newport, it just isn't the case. Cambridge's long hot months have a lot going for them.

First of all, Cambridge is not your average urban sprawl. Green, shady oases like Harvard Yard, Radcliffe Yard, JFK. Park at the Kennedy School and the Cambridge Common (only during daylight hours) offer plenty of space for frisbee games, touch-football and soccer.

Play softball on the Common--a small baseball field is nearly always empty--or take advantage of the University's Commencement-groomed lawns for some sunbathing.

If sounds of traffic disrupt your nature-loving in the Square, you still have options.

Summer has advantages that frigid January just can't touch, like the ability to walk, jog or rollerblade Memorial Drive. On Sundays, Memorial Drive is closed to traffic, but a paved path along the river is good enough the rest of the week.

Can't Take the Heat?

Average temperatures in the city can soar beyond comfort level. Concrete has a way of getting quite hot.

To cool off close to home, the fountain in front of the Science Center is perfect. Prance on top of the fountain's rocks, but, be warned, the misty appearance is deceptive--if you plan to go in with your clothes on, remember that the fountain is significantly wetter than it looks.

If you still can't take the heat, go inside. The University library system offers a number of air conditioned sancturies with all the summer reading you could possible want.

Curl up with a book, but note that not all libraries are well-suited for this. Widener's stacks have a reputation for getting quite steamy at times. The lack of ventilation is distressing even in the winter, when it is still frequently overheated.

Or go the consumer route. The Square boasts excellent shopping (see related article on shopping below) and affords the opportunity to hop from one climate-controlled oasis to the next.

The Garage, between Mass. Ave. and Mt. Auburn St., is probably the largest indoor shopping area in the Square.

Another place to spend your money on the streets of Cambridge is at the abundance of sidewalk cafes which emerge from winter hibernation as the mercury rises.

Sitting outside at Au Bon Pain is a great place to people watch or challenge a friend to a game of chess.

And once the sun sets, evenings are cool enough to head out and really enjoy the city.

Summer Nights

On weekend nights, musicians and magicians line the streets. The best of street performers can draw crowds of as many as 200. Donate your share of change--it's only polite.

The streets of Cambridge are not the only places to find cheap music during the summer. Free outdoor concerts abound at such venues as the Hatch Shell in Boston and Charles Square in Cambridge.

Boston night life also beckons. While the Square is packed with eateries, the North End is a must for summer visitors seeking excellent Italian cuisine--usually in enormous portions.

The city also boasts a number of nightclubs, though most, but not all, require you be at least 18, if not 21, years of age to enter.

For those who meet the age requirement, Cambridge and Boston also are home to plenty of bars and even a few microbreweries.

Some prefer to grab an ice-cream cone at any of the Square's many locations (see related article below) and enjoy a quieter summer evening.

Got to Get Out of This Place

But if you're really a hick at heart, the Square's attractions may not be your style. There are plenty of places just outside the area to avoid the urban scene.

Ride your bike or take the #74 bus to Belmont center to Habitat for the Environment. It's a 15-minute walk from the bus stop to the site and the first visit is free to students.

While its proximity to a neighborhood school may not satisfy those accustomed to the truly rural, the 80-acre Audubon Sanctuary complete with garden, fields, woods and pond makes a welcome escape for days when the mercury tops 90.

If that doesn't float your boat, take a trip to Walden Woods, where Henry David Thoreau, class of 1832, made his famous retreat.

Best accessible by car, it is a good place for walking, biking and fishing. Just recently, a new center was built there in Thoreau's honor.

Another excellent day-trip is one of the harbor cruises. A wide variety of inner and outer harbor tours are available.

Choose one that lets you get off and tour the islands--some were used for military operations in the Civil War and George's Island, the site of Fort Warren which held about 2000 Confederate prisoners during the war, contains a network of damp, dark tunnels which you can explore. The islands comprise Boston Harbor Island State Park.

Beaches are another good getaway. Local Revere Beach, Carson Beach and Castle Island offer a chance to beat the heat.

(For more destinations outside Boston, see the story on page B-2.)

These Are the Days

However you spend your time here, summer in Cambridge is quite a different scene from the winter months. Cambridge's cold, dreary season doesn't bring street performers or outdoor concerts, and, even if it did, most Harvard students would be too busy to attend.

The slower summer pace allows students to take advantage of many things they would not have time for during the year.

For those arriving in Cambridge as the weather heats up and those staying on while others flee to more hospitable climates, there is a lot to enjoy.

For a summer in the city, it's pretty much ideal.