There are many reasons for this. Some of these are as follows:
1. Because it's colder in the winter and that creates a physical change in the coconut oil.
2. It has
something to do with the high melting point of coconut oil. Coconut oil
turns from a clear liquid into a hard, white solid at temperatures
below 76 degrees. Butter does the same thing. Pull a cube of
butter out of the ref and it is solid. Keep it out on a hot day and it
melts, as the say, like butter.
3. Because the freezing point of coconut oil is high or Melting point of coconut oil is less.
And many more....