What's the climate like in Iowa, USA?

Iowa City is located in the eastern part of Iowa in the midwest of the United States, and its climate is roughly equivalent to the weather north of the Great Wall in China. It's cold in winter and hot in summer. In winter, the temperature is as low as MINUS 30 degrees Celsius, and it often snows, but the temperature changes frequently and it is not cold for a long time. The temperature can be as high as 35 degrees Celsius in summer. It is rainy in spring and autumn.