It all depends on where you live and what type of butter you have.
For example, some blocks of butter are best kept out of the refrigerator as they become too hard to spread when cold. A good thing to do if leave the butter in the refrigerator overnight but remove it during the day, this allows the butter to be spreadable but not too soft. However if you live in a warm area it is best to keep your butter in the refrigerator as the consistency will become very runny if left out during the day.
Margarine is often softer than butter and can be kept in the refrigerator through the day and night. Try looking for easily spreadable butters, but the choice is yours.
