Two of rock's biggest bands square off against each other in the first round of Ultimate Classic Rock's quest to find the Greatest Summer Song. You can vote for either the Beatles' "Here Comes the Sun" or the Who's "Summertime Blues" below.

We’ve selected 32 of classic rock’s best summertime songs, and paired them off in 16 first-round duels. Over the next five weeks the field will be repeatedly cut in half by your votes, until we arrive at the greatest summer song ever made.

George Harrison wrote "Here Comes the Sun" for the Beatles' Abbey Road album, the last LP they recorded together. After years of having his material brushed aside, Harrison was growing frustrated with the group by summer 1969, when he recorded the song with Paul McCartney and Ringo Starr (John Lennon, who was recovering from a car accident, didn't take part in the sessions). Still, it remains one of his most hopeful songs, and one of the cheeriest in rock history.

On the other hand, the Who's version of "Summertime Blues," which was co-written and originally recorded in 1958 by Eddie Cochran, is one of rock's grumpiest songs. Told from the point of view of a kid who has no money, no job and no future, the song has long been a favorite of garage rockers and other slacker types (Blue Cheer scored a Top 20 hit in 1968). The Who often played the song in concert, including on their 1969 tour, which was documented on 1970's historic Live at Leeds album.

So which one will earn a trip to the second round? Listen to both below and make your call. You can vote once per hour in each of the 16 first-round Greatest Summer Song battles until voting closes on July 27 at 11:59PM ET. Your choice for the Greatest Summer Song of all time will be revealed on Aug. 25, 2015.

Listen to the Beatles Perform 'Here Comes the Sun'

Listen to the Who Perform 'Summertime Blues'

See the Beatles and Other Rockers in the Top 100 Albums of the '70s