As has been widely anticipated, March sales were strong for most retailers. The warehouse club business was no exception. All three players -- Costco (NASDAQ:COST), Sam's Club (a division of Wal-Mart (NYSE:WMT)), and BJ's (NYSE:BJ) -- reported nice gains.

Costco in detail
When looking at warehouse club performance, I like to start with Costco, the largest and most dominant player in this field. March comps were up 6%, with U.S. stores gaining 5% and international stores notching a 7% rise.

This was slightly higher than the 4.8% comp increase expected by analysts polled by Reuters. It also falls right in line with year-to-date performance; the company grew comps 5% in both previous quarters.

Costco ended the March reporting period on Easter Sunday. Since the clubs were closed on Easter, sales this year included one fewer day than last year. This lost day hurt March sales by an estimated 1%-2%, which the company will pick up during April.

Retail sales releases these days are filled with gory details, but I won't bore you with a litany of additional numbers. Suffice to say that both customer traffic and the average ticket amount were up, higher gas prices helped a little, as did foreign currency effects, and cannibalization from new store openings was under control. Costco management is doubtlessly pleased with the month.

What about Sam's and BJ's?
Comparing the club operators can be a little tricky. Both Sam's and BJ's end their periods on Saturday, so they didn't miss the Easter Sunday selling day. Sam's reported 7.4% comp growth, with BJ's chiming in at 5.5%. On the surface, it looks like the big three are all bunched together, with Sam's perhaps nosing out on top for the month. But given the calendar differences, I add 1%-2% to Costco and subtract a similar number from the other two (BJ's confirmed that number; Sam's did not). With these adjustments, I think Costco beat the other two by a few points.

Does March matter?
Yes and no. It's a five-week month and the start of spring selling season, so yes, it's important. But with Easter calendar switches, and early-season weather patterns, I put little stock in March on its own. Wal-Mart has already warned that April comps will be flat to negative, and it will be "challenged" to hit first-quarter earnings estimates. Fools are best advised to wait until we can put March and April results together.

At the very least, March retail sales results tell us that the U.S. consumer is still spending. Whether that same consumer is saving anything is a different question.

For more on March sales results, check out:

Costco is a Motley Fool Stock Advisor selection. Wal-Mart is a Motley Fool Inside Value recommendation. You can try either market-beating newsletter free for 30-days.

Fool contributor Timothy M. Otte surveys the retail scene from Dallas. He welcomes comments on his articles, and owns shares of Wal-Mart, but none of the other companies mentioned in this article. The Fool has a disclosure policy.