Ya'an Outlook
Ya'an has a monsoon-influenced humid subtropical climate and is largely mild and humid. The presence of the mountains to the northwest greatly affects the city's climate. In the short winters, they help shield the city from cold Siberian winds. January averages 6.3 °C (43.3 °F), and while frost may occur, snow is rare. Summers are hot and humid, with highs often reaching 30 °C (86 °F), yet extended heat waves are rare; the daily average in July and August is around 25 °C (77 °F). Rainfall is common year-round, though in winter it tends to be light, and is particularly heavy in summer, when warm, humid southerly or southeasterly winds blow against the mountains, causing orographic lift to occur, enhancing rainfall. With nearly 1,700 millimetres (67 in) of rainfall occurring on 213 days per year, Ya'an is also known as the "Rain City". In addition, rain often falls at night, so fog is not a common occurrence.