Do publishers pick certain seasons for a show to be published? I have been thinking about this for a while, but I haven't really been watching enough just-released anime to form a picture of what type of series are broadcast when. 

I'm interested to know if publishers pick certain seasons for a show to be published? Or do they release it as soon as they have the idea, in the nearest season?

I'm sure there could be lots of reasons for a show to be published in a particular season instead of another one:


Scheduled Christmas Episodes, Valentines Day/White Day
School Holidays / School Year
Seasonal trends for particular genres
Publishers know a similar title / popular title will be coming out


I don't really see any trends with this though.

The answer could be very publisher-dependent, but is there any evidence that any companies knowingly wait until a preferred season?
I think most Publishers dont, since most anime are aired for 3 months and contain a timespan of way more Tome(like in most School Anime they contain a whole school Year), but I think there are trends of Genres over the seasons, for example, most 'Harem' Anime are started in winter/spring and most sport anime are aired in summer.