How speculative is the stock market right now? Only medium hot, according to the traditional indicators.

A growing number of forecasters are predicting declines of 5 to 15 percent in the popular market averages, with the summer the low point. But after that, most expect even higher prices ahead -- because, they say, speculation hasn't yet gotten out of hand.

Here's a reading of what the leading sentiment indexes have to say:

*Indicator Digest's New Speculation Index: Measures the trading volume on the New York Stock Exchange compared with the volume on the American Stock Exchange (adjusted for the number of shares traded on each). Because the Amex lists more lower-priced shares than the Big Board, it's a good proxy for what small investors are doing, and, typically, small investors get the most excited at a market top.

By this measure, speculation still has a way to go before tipping over the edge. It's "up somewhat," ID's editor, Robert Cardwell, told my associate Virginia Wilson, "but not at an unusual high."

*Indicator Digest's Cat-And-Dog Index: Tells you how well low-quality stocks are doing relative to the blue chips. ID defines "low-quality" as stocks selling under $5, which is where the public most likes to play.

This indicator is high and rising, although not as high as the l983 peak -- suggesting that it, too, has room to run.

But Cardwell thinks that it may not be as good a measure as it was in the past. "Since the '83 shakeout of speculative stocks, the public hasn't come back to the market except in mutual funds," he said. So the number of small trades may not reflect the same level of speculation that it used to.

*Mutual Funds Cash-Assets Ratio: Looks at the amount of cash in mutual funds that is waiting to be invested. Like the other sentiment indicators, it's based on the theory that popular opinion is always wrong. Mutual funds are always fully invested in stocks at market tops (when they should have been selling instead of buying) and heavy with cash at market bottoms (when they should have been picking up stocks cheap).

Today, this ratio is "in decent shape," in the opinion of market analyst Martin Zweig, author of a new book on technical analysis called "Winning on Wall Street" (Warner Books; $20). The funds have acquired a lot of new money for Individual Retirement Accounts and soon will be putting it into stocks.

*Number of Secondary Offerings: Measures the amount of new stock issued by a company that already is public (as opposed to new issues, from companies just going public). This measure also includes large blocks of older stock that a major investor has decided to sell through stockbrokers. The more speculative the market, the faster these issues sell and the quicker the companies pump them out.

The current number of secondaries is relatively high, and their dollar value, as counted by Indicator Digest, nearly twice the level of the '83 peak. "It suggests that knowledgeable people are dumping," Cardwell said. Zweig rated it "moderately negative" for stocks.

*Insider Selling: Follows the number of corporate insiders who are getting out of the company stock. Right now, said The Insiders newsletter, edited by Norman Fosback, the trend of insider selling is neutral -- neither optimistic nor pessimistic. And that's good news for the market, he concludes. Insiders haven't yet started to dump in a major way.

The most active insider buying, Fosback said, is among the smaller, more growth-oriented stocks on the American Stock Exchange and over-the-counter.

*Investment Advisers: Measures the number of professional optimists compared with the number of pessimists -- and again, the majority is always wrong. Right now, the optimists are ahead by four to one -- "not good," Zweig said, "but not fatal."

Fosback's view is stronger. "Very bearish," he said. In fact, he reads the indicators as suggesting a weaker market for the long term.

Zweig's own sentiment index, compiled from many technical indicators, recently dropped into the pessimistic range. But he's still an optimist -- because investors cannot live by sentiment alone.

More important than all of the other indicators is the attitude of the Federal Reserve, and whether it will keep on supplying enough money to keep interest rates on a downward slope and to fuel further stock-market speculation. Zweig is betting it will. "The risk of a short-term drop has heightened," he said, "but the major trend is still positive."