April is here and with the arrival of the fourth month of the year comes the opportunity for new seasonal ideas with exchange traded funds.

While seasonal ideas have proven rewarding in the past, investors should remember that seasonality, be it for sector ETFs, commodities fund and other asset classes, should be used with other indicators to gain more powerful confirmation. After all, seasonality is not a free lunch.

That much was seen in March when the Financial Select Sector SPDR (NYSEArca: XLF) gained just 0.6% and the Consumer Discretionary Select Sector (NYSEArca: XLY) lost 3.4%. Those performances are relevant because XLF and XLY are usually the top two of the nine SPDR ETFs in March. [Sector ETF Ideas for March]

XLF, the largest U.S. sector ETF by assets will get another chance to prove its seasonal strength because, since 1999, the ETF’s first full trading ETF, the fund has been the second best SPDR in April, according to CXO Advisory.

Another disappointing sector fund will get a chance to set things right in April. The Industrial Select Sector SPDR (NYSEArca: XLI) is usually the best of the nine SPDRs in April, according to CXO.  XLI, which was one of three best SPDRs in 2013 as industrials were the Dow’s best-performing sector, is flat this year. [Industrial ETFs Boosted by Aerospace Stocks]