Welcome! If you're running the UTEC version 5 software/firmware you can set your Temperature Comensation settings in the parameters area of the UTEC. The colder it gets, you'll want to pull timing and add fuel as a general rule. I'm not talking about a ton of timing, maybe -.5* (half a *) up to -2* if it's really cold (like less than 0c). Maybe add up to +.2 to .3 fuel. It's all under the temp settings.
If your map doesn't knock in the day and only when colder at night then that's what I'd do.
If it's knocking in the day and night you will want to take a little timing out where it's happening and see if it corrects it. You can then try to add a little fuel in that area. I would still make the temp correction settings to compensate once you've got the knocks taken care of.
If you're still confused call TXS Aus and have them walk you through it