January in Ishim is the most freezing month of the year. In January, the weather in Ishim is typically freezing. Average daily high temperature in January is about 15 degrees below zero. On average, Ishim has 25 cloudy, 3 snowy, and 3 sunny days in January. The snowfalls are usually light. January as well as February, April, October, and December is considered the most uncomfortable time to visit Ishim.