Fort Smith Arkansas
|-- Taken from the Local Climatologial Data publication for Fort Smith, Arkansas issued by the National Climatic Data Center|
Fort Smith is located on the Arkansas River at its confluence with the Poteau River and at the point where it enters the state from Oklahoma. The river valley is broad and fairly flat, although elevations in the city of Fort Smith range from 390 feet at the river to 700 feet. Within 20 miles to the north are the Boston Mountains with elevations to about 2100 feet and about the same distance south are the Ouachita Mountains with a maximum elevation of about 2600 feet. The general terrain in the area consists of low broken hills separated by creek and river bottom land.
The surrounding terrain has a definite influence on the weather at Fort Smith. Under conditions of light wind, the direction is prevailing northeast throughout the year. When there is a fairly strong inversion these winds may remain northeasterly even though a strong gradient is present. Although infrequently, dense fog will move in from the river to the east and persist longer than would be expected. In the summer this will result in uncomfortably high humidities and in the winter in cooler temperatures than reported at surrounding stations. Summertime temperatures in the mountains to the north are generally several degrees cooler than in the river valley.
Temperature extremes do occur. In summer there is an average of 10 days when the temperature rises to 100 degrees or higher. On the other hand, in about one year in five, the temperature does not reach 100 degrees. Wintertime temperatures rarely fall to zero or below.
Rainfall is well distributed throughout the growing season. January is the driest month, May is the wettest. The difference is almost 3 inches, but rainfall is generally adequate for agricultural pursuits. Summer precipitation comes in the form of convective showers. Dry spells occur, but true droughts are infrequent.
Snowfall varies widely from season to season. Although snowfall averages a little over 6 inches, some years go by with no measurable amount being recorded. Ice storms are much more frequent, causing many problems with traffic movement.
Based on the 1951-1980 period, the average first occurrence of 32 degrees Fahrenheit in the fall is October 30 and the average last occurrence in the spring is April 3.