Like nicholma, I'm a late-nighter in any season.
In the summer I'm busy working in the yard, coaching LL soccer, soaking up as much as I can of the relatively short New York summer days - but oddly enough - I also seem to stay up later and do a little more modelling in the summer too. go figure !
A note to mbalint... First of all - WELCOME ! - I see this is post # 1 for you. I have a few little ones myself . (Actually some of them are not so little.) One of the advantages of modelling for me is that it is a hobby that doesn't detract from my time with the family. Like I mentioned above - I usually model after they're all in bed. This works for me.
I have found that I need to have a totally different frame of mind if I am modelling alone - for myself, or if I am modelling with my kids. Once in a while I'll work on "MY' projeccts on a Saturday with the kiddo's around - but I limit the type of work I do. I wouldn't recommend it with an 18 month old. They move quickly, without warning, in unexpected ways. I'm sure you know what I'm talking about. My youngest is 4 - I can usually anticipate mischief before she acts.
Another tip - display / store models on high shelves. My 6 yr old recently tried to "play the strings" on my Fairey Swordfish. He was probably just performing a QCcheck on the lines for proper tension. After the third one snapped, he stopped. I guess that means it failed. Rigging is difficult enough when you're building a model. I haven't yet found an adjective to describe re-rigging a finished 1/72 scale biplane. The model is on a higher shelf now.