Mong Cai's climate is characterized by mild winters and warm summers. Spring arrives in February with temperatures rising to around 20-22°C, gradually warming up to an average of 23°C by March. Summer months from April to June bring hot and humid weather, with temperatures often reaching the mid-30s Celsius. Autumn brings a welcome respite from the heat, with temperatures cooling down to the mid-teens Celsius in December and January. The warmest period is usually from May to August, while the coolest months are February and March.