If you want to see a field of the mustard flower with your eyes, then this is the best time. There are mustard farms all around the countryside in Bangladesh. It seems like a yellow ocean in whichever direction you look. The air is filled with the charming fragrance of a mustard flower. Although mustard is the principal oil crop in Bangladesh. Farmers of Bangladesh are now passing busy time to harvest mustard which is a winter crop during Rabi season (October-February).