I slept out in my WBBB the other night and ouch it was cold. I had my new 3 season full length Incubator installed and 3 season Burrow TQ on me but still got quite the chill. I went to bed in shorts and a fleece top, which was a big part of the problem I'm sure. I was cold enough to get up and change. I put on some jeans, doubled my socks, added a thin hoodie. Since it felt like I was getting cold from below I threw a ccf pad in the pad pocket. That combo warmed me up enough to actually sleep.
I didn't know the exact temperature, so I just looked up Environment Canada's historical data for that night. The nearest weather station shows it was about 7C (45 ish F) at the time that I got up for the extra gear. I was about 80 kms away from there and at a much higher elevation, so I wouldn't be surprised if it was close to freezing.
I'm starting to wish I had bought the winter UQ instead. The mountains get mighty chilly at night, and it's only going to get worse with fall coming. I'm thinking it might be time for a DIY second UQ layer or something like that. I still have the PLUQ I made.. perhaps that in combination with the HG UQ will be warmer.. Maybe a AHE BBO too... even with the hoodie my face was cool all night. I'm also thinking that my tarp setting may have been a factor. I had it in porch mode which let the breeze in. Dropping that side down may have helped.