Yanji has a continental climate moderated by the surrounding hills. Winters are cold but not as brutal as Songyuan or Changchun; January averages around minus thirteen degrees. Summers are warm, with temperatures reaching the mid-twenties in July.
The best months are May through September, when the hills are green and the outdoor food culture of the city is at full operation. The annual Korean folk festival in September, celebrating traditional music, dance, and sports, is worth timing a visit around if you have the flexibility. Autumn is particularly attractive — the forests around the city turn in October and the weather is crisp without being severely cold.