It's anybody's guess

it's anybody's/anyone's guess

It is uncertain or unknown. Why do dogs and cats hate each other? Well, it's anybody's guess. No one has been able to determine why my daughter has been having nightmares—apparently, it's anyone's guess.
See also: guess
Farlex Dictionary of Idioms.

It's anybody's guess

No one knows, so anyone's guess is as good as anyone else's. A: When will the messenger be here? B: It's anybody's guess.
See also: guess
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • it's anybody's/anyone's guess
  • anybody's/anyone's guess
  • anyone's guess
  • be anybody's guess
  • be anybody's/anyone's guess
  • say over
  • be on the market
  • why doesn't (one) (do something)
  • why don't you?
  • heap coals of fire on someone's head
References in periodicals archive
It's anybody's guess whether the pre-teens will want to run home screaming, or rise to the challenge, and maybe even have a life-changing epiphany.
It's anybody's guess whether the preteens will want to run home screaming to their folks, or rise to the challenge, and maybe even have a life-changing epiphany during their experience.
But in the Supreme Court, it's anybody's guess. Is this the 'normal' that justice-seeking Filipinos are stuck with?
What we know for sure is that there is still plenty of cause for optimism, but the Bears -- players and coaches alike -- were awful in Miami, and now it's anybody's guess as to what to expect next and how far away this team actually is from being ready to win.
The top ranked all-rounder is facing a long wait on the sidelines with the infected finger on his bowling arm -- while it's anybody's guess if it's going to rule out the 31-year-old from next year's ICC World Cup.
Lib Dem MSP Liam McArthur said: "BTP integration has cost more than a million so far and it's anybody's guess what the overall expenditure might end up.
While it's anybody's guess who will win the lawsuit, it's possible that cord cutters might be the biggest winner from the trial.
It's anybody's guess who the players in the pool will be although the speculation is Christian Standhardinger, Troy Rosario, Stanley Pringle, Terrence Romeo, Marcio Lassiter, Arwind Santos, Mo Tautuaa, Chris Ross and R.
There's a glimpse of a gallows and new black robes in the trailer so it's anybody's guess as to how she gets her revenge.
It's anybody's guess that the lawmakers will want to relax and not show up," a source said.
"It's anybody's guess how Dinky reached Al Barsha South, 28km from the airport.
It's anybody's guess what the next four years will bring, with Trump's murky stances on women's rights, LGBTQ equality, nuclear arms, national security, the economy, and health care.
Widnes's 18-12 victory at Wigan a week ago was the best in their recent history but it's anybody's guess how much that encounter took out of them and there are better bets on the card.
Whatever they finally decide, if they are able to reach any consensus, it may well be too little, too late for this election - in which case, it's anybody's guess what the Republican Party of the future will look like.
(But my father was also quite a storyteller, so it's anybody's guess about the truth of any of this.)