May is the first month in what historically is the weakest six-month period for stocks, and the major equity benchmarks did nothing to break that ominous precedent on Friday, May 1, as the S&P 500 slipped 2.8% in the first trading day of the month.

Historical data indicate May isn't as bad as the reputation implies. Over the past two decades, the S&P 500 averaged a flat performance in the fifth month of the year.

There's another trend that defies May's usually bleak reputation: each of the original nine sector SPDR exchange-traded funds average positive returns in the fifth month of the year, albeit mostly of the modest variety.

What follows is a look at four SPDRs and their historical May trends, which could unearth clues about two to embrace and a pair to possibly avoid.

Consumer Staples Select Sector SPDR (XLP)

The Consumer Staples Select Sector SPDR XLP is usually the best-performing sector SPDR ETF in the fifth month of the year, averaging a gain of close to 1%, according to CXO Advisory data.

XLP, the largest consumer staples ETF, is a defensive idea, but one not immune to broad market swoons. While there's plenty of evidence to suggest the likes of Clorox Co CLX, Walmart Inc WMT and others are valid coronavirus plays, XLP is lower by 8.5% year-to-date.

The best thing that can be said about that is that the showing is besting the S&P 500 by 364 basis points.

XLP, which yields 3%, is coming off an April gain of 7.6%.

Health Care Select Sector SPDR (XLV)

The Health Care Select Sector SPDR XLV only slightly trails the aforementioned XLP for top May honors among the Sector SPDR ETFs. Historical data indicate that if XLV rewards investors in May, they may not want to be hasty in taking profits, because the health care ETF is also usually the second-best performer in June, according to CXO data.

XLV is coming off a stellar 14.8% gain last month, underscoring the fund's near-term sensitivity to positive coronavirus treatment and vaccine efforts among its larger components, including Johnson & Johnson (NYSE: JNJ) and Gilead Sciences, Inc. GILD.

Consumer Discretionary Select Sector SPDR (XLY)

The Consumer Discretionary Select Sector SPDR XLY usually posts a slight May gain, but it's got some work to do to live up to its May precedent, as the fund fell 3.74% Friday following Amazon.com, Inc.'s AMZN.

It's no so much that the report was bad, but investors keyed on the company's coronavirus-related spending expectations for the current quarter, which include essentially all profits going out the door to deal with the pandemic.

That's relevant for XLY because it has one of the largest Amazon weights among all ETFs. Another test for the fund looms Friday with the arrival of the April jobs report.

Financial Select Sector SPDR (XLF)

The Financial Select Sector SPDR XLF is being pressured this year by low-interest rates, among other factors, but that's baked into the fund at this point. It usually is the second-worst May SPDR behind XLY before moving onto usually being the worst performer in June, according to CXO.

XLF, historically, is the leading sector SPDR in July and September. The fund gained almost 13% last month.