一月 (yīyuè) means "January," the first month of the year. Chinese months are formed by combining a number with 月 (month): 一月 (January), 二月 (February), and so on through 十二月 (December). This system is straightforward and easy to learn.
一月是一年的开始,大家都很有干劲。
yī yuè shì yì nián de kāishǐ, dàjiā dōu hěn yǒu gànjìn.
January is the start of a new year, and everyone is full of energy.
北京的一月特别冷,经常下雪。
běijīng de yī yuè tèbié lěng, jīngcháng xià xuě.
January in Beijing is especially cold, and it often snows.
他计划一月份去南方旅行。
tā jìhuà yī yuè fèn qù nánfāng lǚxíng.
He plans to travel to the south in January.