When does the cold season occur?

Cold spell is a typical weather phenomenon in Northern Vietnam, marking the complete end of the “remnants” of the previous winter, the last cold spell before entering summer. This cold spell usually lasts for several days, accompanied by drizzle and cold wind, causing the temperature to drop significantly compared to the previous days.

Cold spells often occur in the third lunar month, when the weather has warmed up, even some days are quite hot, but suddenly a cold spell returns.

Why is it called the cold of Ban? According to folklore, Ban was kind but clumsy. She loved her husband very much, and from the beginning of winter she started weaving cloth to make clothes for her husband to protect him from the cold. However, because she was clumsy, she kept fumbling, spinning the thread but not knowing where to put the needle, putting the thread into the loom but the shuttle and bobbin were broken, finding one thing but missing another.

Just like that, when she finished sewing the sweater, winter had long passed, the weather had turned warm, and summer was about to come.

Too sad and disappointed, Ban cried. The Jade Emperor felt sorry for her and immediately made the weather cold again for a few days so that her husband could have a chance to wear the warm clothes his wife made. That is why this last cold spell of the season is popularly called Ban's cold. There is a folk poem:

"Miss Ban sews clothes for her husband
"Three months of sewing is not enough to fully heal the wrist".

Scientifically, the cold spell is the result of late cold air from the North flowing in late March or April. Although winter has passed and the weather is warming up, these cold air waves can still cause a sudden drop in temperature, creating a short cold spell. This is a normal phenomenon during the transition from spring to summer.

Although it only lasts for a few days, cold weather can still affect people's health, especially the elderly and children. Sudden changes in temperature can easily cause colds, sore throats and respiratory diseases.