To be sure, -25F is plenty cold. I've lived one place where the temperature got that cold, and in crappy student housing where we filmed over the windows and you could see the plastic bellowing in the wind, and where a 2L Coke bottle in the pantry froze. Not something I want to do again.
https://www.isws.illinois.edu/statecli/cuweather/cu-averages... says the record low temperature for Champaign-Urbana, Illinois was -25F "on four(!) occasions: 9 Feb 1899, 13 Feb 1905, 19 Jan 1994, and 5 Jan 1999."
To be sure, -25F is plenty cold. I've lived one place where the temperature got that cold, and in crappy student housing where we filmed over the windows and you could see the plastic bellowing in the wind, and where a 2L Coke bottle in the pantry froze. Not something I want to do again.