The answer to your question really depends on where you're from. To me, it'll likely be fine, and I could even go swimming on some days. A bit cool but a lot warmer than "home" at the same time of the year/season. To others, it may be frigid. For a Russian or especially an Inuit, likely very balmy.
Example. Taipei average high/low temp is 19/16C in December. In Iqaluit, the average July (high of summer) hiigh-low is 12/4C. An Inuit will probably find it unbelievably hot in Taipei in the middle of winter.