Bitcoin hasn't and probably isn't going to shoot up any time soon. That's the reason why altcoins are falling as well. As long as bitcoin is falling and it's leading the market trend, altcoins are going to be in a bear market as well.

Instead of a few weeks I actually think that this bear market could last until the end of the year.

So yes, it's safe to say that it's altcoin winter now. Don't expect a lot of profits from investing in big market cap coins for the year as they are just generally going to follow bitcoin's movements, instead, look at some smaller market cap stuff if you do want to trade for a profit this year or just hold your bags for now until the bear market subsides.