Wake me up when September ends. The new month, historically the worst for the stock market, hasn’t quite started yet but it’s already looking like being fraught with risk.

The market is getting more confident that the Federal Reserve will hike interest rates on Sept. 16, even if Federal Reserve Chairman Kevin Warsh didn’t quite say as much in his Jackson Hole speech Friday. His policy of no forward guidance makes the crumbs he does offer even more enticing for market watchers. 

The odds crept as high as 62% to start the week, up from 57% on Friday, according to CME’s FedWatch tool. Oil prices aren’t helping, rising above $90 a barrel after the U.S. attacked Iran over the weekend.

It’s too early to call a tech pullback, or even a wobble for that matter. Stocks have had a good month, the Nasdaq Composite is up 4% in August and the Dow Jones Industrial Average is set for a fifth consecutive monthly gain.

But the rally could come to a halt, or worse, if rate-hike bets become a sure thing. Suddenly, Friday’s August jobs report takes on a greater importance. If the labor data come in strong, it’s unlikely to be a green day for stocks.

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