North Dakota's climate is continental and is characterized by large variances in temperature, both on a seasonal and daily basis. Precipitation ranges from low to moderate, and air flow through the region creates windy conditions.
North Dakota is affected by regular changes in atmospheric air masses. Air masses from the polar region bring cold, dry air to the state. Northern Pacific air masses produce warmer, drier conditions, and tropical masses bring warm, wet weather. The Rocky Mountains frequently block air masses from the southern Pacific Ocean from reaching the state.
North Dakota's average annual temperature ranges from 37° F in the northern part of the state to 43° F in the south. January is the coldest month. Temperatures average from 2° F in the north to 17° F in the southwest with an average of fifty days below 0 . July is the warmest month with temperatures averaging 67° F in the north and 73° F in the south. Temperatures over 90 are common. North Dakota's highest temperature was 121° F and the lowest -60° F, were both recorded in 1936.
Annual precipitation ranges from 13 to 20 inches a year. The average increases from west to east, with the southeast receiving the highest average precipitation. Winter precipitation is highest in January. June is the wettest month receiving 3 to 4 inches of rain. Areas such as the Turtle Mountains receive higher rainfalls than the surrounding plains, due to higher elevations.