WASHINGTON HAS four seasons, all right: cherry blossom, Skyline Drive, dog days and fog days. Welcome to February, the climatic tease, with daylight languor that lures you out and an after-dark hauteur that insinuates itself into your bones. It's like a San Francisco import; and it makes for contemplative, romantic fireside tippling.

This week, there are two particularly good reasons to wander where the sparks fly. Tuesday is Mardi Gras -- Fat Tuesday, the last chance to luxuriate in the sensual before going lean and spiritual for Lent. (Incidentally, have you ever noticed that when they say Lent lasts 40 days, they're cheating? It's 40 days not counting the Sundays. If you give up something like chocolate, that extra week's worth is tough!)

Thursday is, of course, Valentine's Day, which despite being a fixed-date holiday seems to take otherwise organized suitors by surprise. And two of the most alluring fireplaces in the Washington area are in the new Ritz-Carlton Pentagon City Hotel, probably the prettiest setting for a subway stop since the Smithsonian institutions themselves.

The Ritz-Carlton's Lobby Lounge has the airy, armchair atmosphere of a Victorian parlor, a more flowered-print and less frondy Palm Court a` la the Plaza in New York. It makes an ideal setting for high tea, and indeed a superlative scones-and-salmon tea is served there seven days a week between 3 and 5 (reservations recommended), seguing comfortably into the cocktail hour.

Actually, though the lounge menu refers to "the martini hour," any temporal restraints are only theoretical. This is martini mecca, offering not merely a variation or two but 12 distinct versions, ranging from the classic (pure, dry and extra dry and Gibson) to the trendy (Cajun, Campari, Cointreau) to the label-conscious (the Citrus with Absolut, the Silver Bullet with Tanqueray or Stoli) to romantic (a James Bond Martini, presumably shaken, not stirred). The most extraordinary may be the Pear Martini, a sleek and deadly shooter for sophisticates. (The Bombay gin and cracked-pepper shooter we used to call a Sgt. Pepper is not on the menu, but could surely be had for the asking.)

The Ritz also lists almost that many champagne (Domaine Mumm, actually) cocktails, including Pimm's, kirs, juleps and black velvets; and a short list of wines by the glass. It offers several ports and sherries, plus a half-dozen cognacs ranging up to the definitive Remy Martin Louis XIII at $70 a glass. Later dining is restricted to light fare -- smoked salmon, pa~te', satay, spring rolls or cheese and fruit -- and desserts.

There is already one lovers' special on the menu: one ounce of Beluga Malossol caviar, a half-bottle of the Ritz's own brut cuve'e champagne and a rose, set up and delivered at $75. However, there are other special Mardi Gras and Valentine treats in the making; at the bar, ask for David.

The same fine spirits and light fare are available at the smaller settings fireside in the Grill, a darkly gleaming paneled room like an old country estate library with the added romantic attraction of live piano. However, the Grill has a more stringent dress code (jacket, no jeans) and a mid-formal atmosphere more grand-anniversary style than Carnival.

The Ritz-Carlton adjoins the Fashion Centre mall at Pentagon City; call 703/415-5000. Incidentally, the last Metro leaves for the District at 11:51, so if you're still there at midnight, you'd better either be headed south (in which case you have another half-hour) or planning to spend the night. Which is another romantic idea: See the Daylife column on Page 57.

THREE BY THREE: The natural sympathy between great saxophonists and great singers -- and the stylistic influence each has had on the other -- inspires a showcase of nearly all-local jazz talent Friday at the Kennedy Center's Terrace Theater in another intriguing pop collaboration by the Washington Performing Arts Society and Charlin Jazz Society.

"Saxes & Singers" features Washington faves Paul Carr and Candace DeBartolo and New York improvisational cult hero Sayyd Abdul Al Khabyyr on sax; Billie Holiday specialist Selena McDay and the scat-swift and spirited Pam Bricker & Rick Harris on vocals. The supporting cast is another trio of well-known local talents, pianist Maria Rodriguez, bassist Pepe Gonzalas and drummer Harold Summey. It's almost sold out so act fast. Tickets are $16.50; 202/467-4600.

Incidentally, speaking of DeBartolo brings up an anecdote that shows off the Washington jazz community's extraordinary commitment to developing and supporting new talent. DeBartolo had been performing regularly with Keith Killgo's Krosswinds as well as her own Uptown Jazz Quartet before accepting a European tour offer from Solomon Burke last fall. Killgo then recruited 17-year-old Ari Ambrose, a student at Blair High School in Silver Spring who has only been playing sax for four years, to take her place on Friday nights.

After DeBartolo returned, she and Ambrose played reed to reed at Takoma Station, and she was flabbergasted at his prodigal clarity and consistency of tone. ("Actually, I wanted to kill him," she says ruefully.) And indeed, Ambrose is a remarkable instrumentalist, with an effortless power that suggests he may not even have grown into his big frame yet. Still a bit reticent in his improvisations, at least until he warms up to the group, he seems to look into the music as if it were a tangible construction: He's the first sighted musician with the other-focused look of a blind one.

Ever since they played together, DeBartolo has been alternatingly pushing Ambrose to get out and play more open jams and pulling others in to hear him. That sort of continuity -- Ambrose to DeBartolo to Killgo back to Donald Byrd -- adds a richness and sense of responsibility to jazz that is obviously missing from most commercial music these days.

And while we're on the subject of local jazz jams: Ben Andrews is hosting regular Thursday night jam sessions in the Chicago Room at Cates ($3; 202/363-2600) and the brand-new jams at Hagan's in Rockville jump to Tuesday night (301/738-7172).

NEW ORLEANS, GRAS-TIS: As for Mardi Gras, Washington just doesn't seem to know how to get into the mood. Fortunately, some lucky couple can win a trip to the Crescent City (courtesy USAir), plus various prizes for knowing Mardi Gras trivia, during the all-day celebration Tuesday at Copeland's of New Orleans on King Street in Alexandria, a block west of I-395 (703/671-7997).