Andy Street says the broadcaster is now likely to announce its new HQ in early November.
Birmingham, Greater Manchester and Leeds are vying to host the broadcaster, in a move which will create thousands of new local jobs and see 300 staff transferred from London.
The decision was initially expected to be announced at the start of October, but Conservative Mayor Mr Street said this was now not going to happen.
"The decision is going to be a bit later than we all thought, and we are now expecting to hear at the start of November," Mr Street told the Express & Star.
"It is a decision for Channel 4's board and as is to be expected, they have to go through their own procedures."
Mr Street spearheaded the West Midlands bid, arguing that Birmingham had a compelling case based on 'unrivalled connectivity, the diverse and young nature of our population and the strength of our creative and digital economy'.
The region's successful bid to become the country's first 5G test site has contributed to the city being installed as favourite to land Channel 4, as has its proximity to HS2.
Mr Street said he remained quietly confident of the region's chances.
"We have put a really good bid together and the region has come together brilliantly," he said.
"The launch event we had in June was excellent and I know we could not have done any more. I am extremely hopeful."
Unsuccessful candidates will be considered as the potential location for two smaller creative hubs, which will focus on commissioning new programmes.
Bristol, Cardiff and Glasgow were separately shortlisted as potential homes for the two hubs, but not for the main headquarters.
Channel 4 bosses said they are committed to increasing the amount of money spent commissioning programmes from outside London by £250m over the next five years.