May 25 (Reuters) - Warehouse club retailer Costco Wholesale Corp on Wednesday reported lower-than-expected quarterly comparable sales, hurt by weak sales in April.

Sales at stores open more than a year were flat, falling short of the 1 percent growth expected by analysts polled by research firm Consensus Metrix.

Excluding the impact of fuel and currency fluctuations, sales at comparable stores rose 3 percent, below the average analyst estimate of 4.6 percent growth.

Net income attributable to Costco rose to $545 million, or $1.24 per share, in the third quarter ended May 8 from $516 million, or $1.17 per share, a year earlier.

Revenue rose 2.6 percent to $26.77 billion from $26.10 billion a year earlier.

(Reporting by Ramkumar Iyer and Sruthi Ramakrishnan in Bengaluru; Editing by Sandra Maler)