CLIMATE OF NORTHWESTERN KANSAS

L. Dean Bark and Herbert D. Sunderman
KSU Climatologist Emeritus and NWREC Research Soil Scientist

This report is intended to define the climatic resources of northwestern Kansas as given by the records at Colby. It contains a number of listings of climatic data illustrating how conditions have varied since the late 1800s and, presumably, how they will vary in the next 100 years. These data should be useful in designing strategies for future operations and will provide material for comparing current conditions with those that have occurred in the past.

The city of Colby is located at 39° 23'N latitude and 101° 04'W longitude--about 130 miles from the geographical center of the United States and only 250 miles east of the Rocky Mountains. Then climate of northwest Kansas can be described as continental with large daily and annual ranges of temperature and a summer precipitation pattern. Since the records began in 1893, annual temperature has averaged 52°F and annual precipitation 18.65 inches.

These brief statements, although accurate, tell only part of the story. Seldom are there years with "average" weather. The variability from year to year is an important aspect of regional climate.

Physical Causes of Climate

An area's climate reflects the various day-to-day weather patterns experienced in the region. The magnitude of expected deviations from the average is often as important as the average value. For vegetation to be continuously adapted to an area, it must be capable of surviving the extremes rather than just the average condition.

Except for microclimate (climate in the first 3 feet above the ground), local conditions do not affect the climate of a region very much. The weather of a region and, thus, the climate are largely determined by its position on our spinning planet.

Global Circulation Patterns

Jet Stream. Air circulation within our atmosphere develops weather systems that constantly change and move over the surface of the earth. Because of the rate at which the earth spins on its axis and the fact that the surface of the earth near the equator receives more solar energy than the surface near the poles, the circulation is most intense in a meandering east-to-west stream in mid-latitudes in the northern hemisphere. This phenomenon is called the jet stream, and it initiates and steers large cyclones and anticyclones along its path. How frequently the jet stream passes over a specific location has a lot to do in determining the climate at that location. During the winter, northwestern Kansas is frequently under the track of the jet stream, whereas during the summer, the track shifts north along the Canadian border.

The jet stream pattern in mid-latitudes steers weather systems generally from west to east. Air arriving at a location has been influenced by the surface over which it has been passing prior to that time. For example, air reaching the west coast has spent days passing over the Pacific Ocean and arrives carrying a large amount of moisture. On the other hand, locations on the east coast do not normally experience this marine influence.