The most important number concerning the Washington-Buffalo game Sunday may well be 716 -643-1234.

This is the time of year when weather conditions occasionally have a strong influence on "Playing Football," and late-season games in Buffalo often provide an excellent example. The above number gives an hourly update on the Buffalo weather.

It snowed heavily in Green Bay and in Cincinnati last weekend. Cincinnati still managed to cover a 13- or 14-point spread against the Giants, but Minnesota was unable to make good as a 7 1/2-point choice in Green Bay.

As a rule, favorites have a much more difficult time covering spreads in foul weather. They win, but not by as big a margin as their backers expect. The bigger the spread, the more difficult it usually is for them to cover. They become more cautious, more conservative, more defensive.

Accordingly, anyone interested in supporting the Steelers Sunday giving 20 against Seattle would do well to call 412 - 936-1212 before making a final decision. Giving 20 points in a couple of inches of snow can be brutal, while taking the 20 under such conditions can be like stealing money.

I have no particular feeling about the Redskins against the Bills, except the thought of Marv Bateman punting his line drives to Eddie Brown should terrify the Buffalo coaching staff. Joe Theismann and the Redskins turned into a superior effort against Dallas, only to lose. Seven points doesn't get the job done.

The weather in Buffalo or Pittsburgh or Green Bay is not going to effect my predictions this week, although I will risk a mythical $250 on San Francisco in wintry Minnesota, where the spread has moved up from 7 to 7 1/2. The 49ers are the underdog, of course, and I just can't see Bob Lee directing the Vikings to a big win. If it snows, so much the better. The Vikes, if they win, will happily settle for a 3 or 7-point margin.

The week's more serious selections figure to play either in the warm, or indoors, I like Houston, getting one point, to upset Denver: Oakland, giving 1 1/2 (down from 3) to beat Los Angeles; Baltimore, giving 1 1/2 (down from 2 1/2) to defeat Miami Monday night, and San Diego, giving 3 1/2, to handle Cleveland.

Make it a mythical $500 on Houston, Oakland and Baltimore and $250 on San Diego.

If I could get over my Pastorini complex, I'd have popped for $1,000 on Houston. The Oilers and "Long-Ball Don" have played exceptionally well the last month, losing only at Oakland, 34-29, while easily downing Chicago, Seattle and Kansas City. Houston's 3-4 defense can be as intimidating as Denver's. The Bronco offense is grinding down, and one has to wonder how much longer the Denver defenders can carry the load.

The Oilers appear to be developing a decent running game at long last. If so, and Pastorini cakeep from reverting to his big-mistake plays, this is where the tam with the best record (10-1) in the NFL loses its second game.

Oakland has too much firepower for Los Angeles. The Raiders occasionally go to sleep on defense, but rarely in the game they must win. This is such a game. Pat Haden has done a fine job of rescuing Joe Namath but he is not in Stabler's class. Who is besides Bert Jones? The Ram's conservative offense should work to Oakland's advantage.

Miami is going to miss Vern den Herder against Baltimore. He was the Dolphins' best down lineman and now he's out for the season along with safetyman Charlie Babb. Miami figures to move well on the Colts, but Baltimore scored 43 points on Miami in their first meeting and Jones figures to have another field day, or night.

San Diego has played outstanding ball at home all year. This is a good young team on the way up. So is Cleveland. But the Browns must go with an inexperienced quarterback in Dave Mays and he will be facing perhaps the best pass rush in the American Conference.

In other games, make it Tampa Bay getting 14 over Chicago, Kansas City getting 7 over Detroit. Atlanta getting 5 over New England. New Orleans giving 4 1/2 over the Jets. Philadelphia getting 13 1/2 over Dallas, the Giants getting 10 over St. Louis, Seattle getting 20 over burgh and Washington giving 6 1/2 (up from 4) over Buffalo.

Last Week's Results

Lost $300

Season Totals

Won $5,040

Last week: Detroit, getting 2, lost to Chicago (31-14): lost $275, Cleveland, getting 2, lost to Los Angeles (9-0): lost $275. Denver (28-13) giving one to Baltimore: won $250. Dallas (14-7) giving 6 1/2 to Washington: the 6 1/2 point spread was not available locally, howver, so the $250 will not be counted.

Season Records: 24-9.

Each unit agreed is worth an imaginary $1,000; better risk, $11 to win $10.