Are there any activities/sights that you cannot do in Winter compared to Summer?

Travelling to NYC in late december for 5 days. Just wondering if there are sights (Top of the Rock, Staten Island Ferry for the SOL, etc.) that you wouldn't recommend doing in winter? Travelling with 3 mates from Australia all mid twenties.

I'm aware of things like baseball not being available in winter, im more asking about activities that could be affected by the weather.

Thanks in advance.