These two forecasts from the 12 UTC WRF-GFS this morning illustrate how difficult it will be to pin down the low temperatures to expect tonight and tomorrow night. Both are valid at 05:00 am MST - top is for Sunday morning (tomorrow) and below is for Monday morning. Current low temperature forecasts for the airport from NWS are for 29 F tomorrow morning and 34 F for Monday morning.
But temperatures across the metro tomorrow at 05:00 am have a range of almost 15 degrees in the model forecast due to how light local winds are forecast to be. For Monday morning the model forecasts warming winds to keep temperatures almost 15 to 20 degrees warmer than Sunday - so another bit of a roller coaster ride.