Coconut oil gets freezed in winters because it has low melting point of around 24oC.
If a melting point of a substance is higher than its surrounding
temperature, it will exist as solid but if its melting point is lower
than its surrounding temperature, it will exist as liquid.
During winters the room temperature lies between 10oC-20oC which is much lower than the melting point of coconut oil and thus coconut oil exist as solid.
hope helped u !!