Sort of.
I have a SS MTB primarily for winter mud plugging but it’s also quite good fun to ride it during the summer too so I do.
I have one geared road bike and I’ve just bought a fixed road bike but both are intended for year round use, the fixie is mean’t to take the brunt of my commuting from now on, and the geared road bike will be used for weekend road pootles with mates and the odd commute, up to now it was used for commuting and weekend road riding but I just want the simplest possible commuting bike I can now for minimal maintenance now…
I think it’s more a case of having certain bikes which are more for the summer i.e. I have a Dirt-jump bike which will only come out if the weather is nice, same with the BMX and my DH bike really only seems to be getting “Fair Weather” use now…
Bearing in mind the fact that wet/cold “Winter” conditions seem to make up almost 3/4 of the British year now, it’s probably wiser to invest in all year round usable bikes and kit than heap the cash on a bike you’ll only use for 3 out of 12 monhs and spend most of your time on a scrapper…