September is historically a rough time for the markets. 

The S&P 500 (^GSPC) has clocked a 0.5% average decline during the month since 1950, according to data from LPL Research.

And there's plenty to keep investors on their toes this month

This September features a closely watched Federal Reserve meeting with a high probability of a rate hike announcement. Investors are also watching trade negotiations between Canada, China and the EU, which has been a key worry for the markets over the past six months.

Will stocks buck the trend this year and continue to reach new heights?

After all, stocks traditionally post declines in August as well, but this year, the S&P 500 clocked a 3% gain during the month.