Hi, everyone!

Is it true that most new properties for rent appear on the market in summer as this is when people move from one place to another?

Is there a chance to find a large apartment (5.5+) during winter or early spring?

It's probably more about which moving dates apply in contracts in a particular canton. Usual moving dates are 31st March, 30th June and 30th September so more people will be moving around those dates. You can find places that don't use those, but there aren't so many of them around.

I don't know but I've been intrigued by the big number of people moving recently. In the last week I've seen much more moving activity than I normally do. I live in ZH city...

In my opinion the 30th June one is the most popular moving date for families with school age children.
Lots of family sized properties become available at that time.