Large‐scale driving mechanisms of the lowest and highest annual temperatures in northwestern Iran

The analysis of the daily observed temperature at five stations in northwestern Iran indicates an increasing trend in the highest annual temperature during the period 1980–2018. Based on the ERA5 data, the lowest annual temperatures in northwestern Iran are caused by the cold air advection from the north, accompanied by a lower than long‐term average mid‐tropospheric geopotential height and the development of a strong surface anticyclonic circulation. The highest annual temperatures in northwestern Iran are associated with the mid‐tropospheric ridge building caused by the development of a cyclonic circulation over the Mediterranean Sea and a northward shift of the subtropical jet stream.