The calendar says Fall, but you'd be forgiven if you think it's Summer.

That's because this was the least volatile September on record, but that may not be such a great thing for the rally, according to one top technician.

"In September, you usually see volatility," said the senior market strategist Thursday on CNBC's "Futures Now." "But so far this year, 40 basis points is the average intraday move that we've seen so far on the S&P 500 this September, which is the least volatile ever."

In fact, according to Detrick, this September 's average daily range has been around 0.4 percent.

So what does this mean for the market going into the fourth quarter? Detrick points to the fact that October has historically been the most volatile month of the year, with more 1 percent moves than any other month, so investors can expect a likely spike in volatility.

"Could volatility mean a little bit of a pullback?" he said. "Potentially, or maybe just some 1 percent daily changes which again, historically are normal, but clearly we haven't been seeing too many of them so far in 2017."

However, while the market had traded in a range this month, Detrick says that he does see stocks going higher in the fourth quarter. The key here is that while the S&P 500 hasn't seen too many moves beyond that 0.5 percent range, the fact that it has both hit a record high this month while being up 10 percent year to date is historically favorable for stocks.

"That's only happened 12 times since 1950, and sure enough the fourth quarter is up almost 6 percent on average 92 percent of the time, which is 11 out of those 12 times," said Detrick. "The fourth quarter is usually strong, what I'm getting at is it's even stronger when you have pretty good strength in September and throughout the year leading up to it."

This means that according to Detrick's data, the S&P 500 could actually rally another 6 percent before the end of the year.

As of Friday's close, the S&P and the Dow had their first positive September since 2013.

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