I have two lagers going right now in the garage that gets very cold.
The first is with Wyeast 2124, in the fridge set at 12 Deg.C, even with cold nights the fridge still turns on and off to keep the temp at 12.
The second is using Californian lager yeast, on the bench with no temperature control and no blankets. It is going quite nicely at 15 Deg.C.
The important thing is that when ever I check them any time of the day, the temperature is always constant.
It depends on your environment, shed, laundry or fridge. You need to try it and see what you get, and it will change with the seasons. Once you get a bit of experience you will know what you can do where and when. You still need to watch out for abnormal weather if you are not in a fridge with temp control.
Fear_n_loath