Bryan Adams' "Summer of '69" goes up against Billy Idol's "Hot in the City" during this second round of our Greatest Summer Song battle – and your votes determine the winner.

After starting with 32 of classic rock’s best summertime songs last week, we’re now down to 16 for the second round. Over the next four weeks the field will be repeatedly cut in half by your votes until we arrive at the greatest summer song ever made.

Both of our contestants faced stiff competition in the first round, with Adams escaping a battle against Van Halen's "Beautiful Girls" with a slim 51 percent of the vote and Idol narrowly triumphing over Jimi Hendrix's "Long Hot Summer" by a 53-46 percent margin.

Things won't get any easier for Adams or Idol in this round. "Summer of '69" was a Top Five hit as the fourth single from Adams' hugely popular Reckless album, while "Hot in the City" charted twice, hitting No. 23 upon its original release in 1982 and narrowly missing the Top 40 after being re-released in 1987 as part of the Vital Idol remix record.

So which one will earn a trip to the next round? Listen to both below and make your call. You can vote once per hour in each of the eight second round Greatest Summer Song battles until voting closes on Monday, Aug. 3 at 11:59 PM ET. Your choice for the Greatest Summer Song of all time will be revealed on Aug. 25, 2015.

Watch Bryan Adams Perform "Summer of '69"

Watch Billy Idol Perform "Hot in the City"

See Bryan Adams and Other Rockers in the Top 100 Albums of the '80s