Climate

Spring

The arrival of spring in Fort Smith is heralded by the melting of snow and the lengthening of the days. In mid-March, the weekly gain in daylight is a very respectable 42 minutes. April is the first month that the average daily maximum temperature pokes above zero degrees Celsius, and rain becomes more common than snow. During May, snowfall is still observed but as one goes from May into June, thunderstorms are likely.

Summer

Summer is the time of year when there is light in the sky overnight. At its peak, the sun is above the horizon for almost 19 hours. Daily maximum temperatures in July average 23 degrees Celsius, with the mercury often soaring into the 30s. The highest recorded temperature in Fort Smith was 35.3 degrees Celsius in August 1981. The short nights can be cool, with an average overnight low of 9 degrees Celsius. There is no chance of snow in July, but snow can occur in June and August. Expect rain an average of 10 days per month through the summer. Thunderstorms are common in summer, but most will not last longer than two hours.

Fall

As the days begin to shorten rapidly, the air begins to cool. In almost the reverse of spring, the average daily maximum temperature dips to 4 degrees Celsius and overnight lows average -4 degrees Celsius. The rain of summer becomes snow and the thundershowers subside. Fall is the time of year with the most fog, with an average of four days per month.

Winter

It may be cold and dark, but winter is the best time of year to observe the aurora borealis and meteorite showers in the Fort Smith skies. The sun is above the horizon for just under six hours in December, leaving lots of time to watch the sky. Cloud cover, not the time of day, dictates the warmest and coldest parts of the day because of the very low sun angle, even when the sun is at its peak. The average daily maximum temperature in January is -19 degrees Celsius while the average daily minimum is -29 degrees Celsius. The mercury has been recorded as low as -54 degrees Celsius in February 1947. Snow of a measurable nature can be expected between 10 and 14 times a month.