Climate

A Wyoming glaciated mountain.

Wyoming is a large state occupying about 92,000 square miles. Of that, only about 700 square miles are water.

Only about 400,000 people live in Wyoming. We live in a half dozen cities with populations around 12,000 to 50,000 people. The rest reside in small towns of less than 5000 people.

Wyoming is an open and sparsely populated land. It's common to drive for 30 to 50 miles before passing a single residence. In some areas, a person can drive double that before passing another residence or town.

Topography

Wyoming is a mountainous state. High plains or basins are situated between the mountains. The average elevation across the state is about 6700 feet above mean sea level(msl). And when the mountains are excluded, the average elevation is around 6000 msl. The highest point, Gannet Peak, is 13785 msl. The lowest point is in the northeast corner of the state at 3125 msl.

Wyoming's high altitude and latitude produces a unique climate. Similar sea level climates are found about 2000 miles to the north. That's about three quarters the way up Hudson Bay, in the Northwest Territories. Or it's about the same latitude as Anchorage, Alaska. Areas in Wyoming, with similar soil and water profiles, have the same animals and plants in common with those northernly areas.

In Wyoming, climate is everything. And topography is the most important factor affecting the climate.

Water

Water is the most valuable natural resource in Wyoming. Regardless of all those beautiful mountain photos showing clear lakes, roaring rivers and tumbling water falls, Wyoming is mostly semi-arid to arid. And much of that rushing mountain water is quickly consumed by the dry and thirsty land in the basins.

Precipitation amounts vary widely, from 90 inches in the mountains, to less than 6 inches in the basins. Rapid transitions occur as the mountains acting as cloud catchers sweep the sky clear of precipitation. Most basins are left in the rain shadows of the mountains. And, as most basins are surrounded by mountains, the direction that storms enter Wyoming has little effect on the amount of precipitation seen in the basins. At my house, I get about 15 inches of moisture a year. Five miles south of me, the average is about 32 inches per year. And five miles north of me, the average is about 8 inches per year.

Wyoming's precipitation mostly occurs as winter and spring snow. It's locked up in the mountains and slowly released as runoff, when the snow melts later during May through July.

Temperature

It gets cold in Wyoming. All areas see -25 to -30 degrees F. The higher elevations see temperatures as low as -65 degrees F. The glaciers, in the northwester quarter of the state, are the last remanent of the little ice age. The basins aren't free from extreme cold, as inversions form when cold mountain air settles down and is trapped there.

And it gets hot in Wyoming. In the lower basins, a few areas see temperatures of 115 degrees F. Most basins see temps to 105 degrees F. But much of the state experiences maximum temperatures below that.

These high temperatures are moderated by an equally high diurnal shift which is common at higher altitudes. In the summer, that shift approaches 50 degrees. So, where I live, blankets are used year round, even when the day time temperatures approach 100 degrees.

A hot day, in the mountains, is 80 degrees F. And with the diurnal temperature shift, water commonly freezes at night, even on the hotter days.

It gets hot in Wyoming, but not for long. Most basin areas experience about a month with temperatures above 90 degrees. Almost half of Wyoming experiences less than a week with temperatures that high.

Wind

No matter how it's sliced, Wyoming ranks first, in the nation, for wind. The average wind speed across the state is about 13mph. Topography amplifies the wind effects. Sudden and drastic changes, in the wind, often precede precipitous changes in the temperature and weather. Every year, a few people are lost in Wyoming's open spaces. When, on a warm, short sleeve day, a raging blizzard is rocketed into Wyoming. And topping the mountains, catches them unprepared.

The jet stream parks itself over Wyoming in the winter. It's common to have sustained surface winds above 40mph, with gusts above 60mph, for several weeks at a time. In the winter, when the wind stops, trouble brews. Temperature inversions quickly settle into the basins. And a lull often precedes the next blizzard by a day or so. As a storm approaches, a combination of cold inversion temperatures, high winds and winter storm weather produce extreme conditions.

Drought

Drought is a fact of life when living in a arid land. And Wyoming is drier than ever. The west is in an extended drought, that has lasted all my life time. Wyoming has been in an extreme drought for over 5 years. This has left the land parched. The loss of vegetation and the stress on the wild animals is almost unbelievable. It has a tremendous emotional effect on me, as I ponder the changes that have occurred since my youth.

And yet, this may be as good as it's going to get. Researchers have studied tree ring growth and plotted the various drought cycles. Droughts have been more intensive and lasted longer than this one. Unfortunately, few humans inhabited the area during those times. With global warming, those conditions are returning again.

Plant Growth

Typical Wyoming Basin.

Plant growth is directly linked to the climate. The mountains have a growing season that is wet, cold, windy and short. Because of the abundant moisture, the mountains have an abundance of plant life. It's slow growing and fragile.

The basins have a growing season that is dry, hot and cold, windy and short. The lack of moisture is the most constraining factor for plant growth.

The chart above details the number of frost free days. It's interesting to note these aren't consecutive days. Frost or freezing temperatures can occur anytime, especially near the mountains. Most basin areas can see about 100 frost free days. Higher areas experience less than three frost free weeks.

Climate Versus Honeybees

Wyoming is a tough place for honeybees. The mountains have the flora and the water. But it's too cold and the season is too short to keep bees there. The basins are hotter and have longer seasons. But they are too dry and lack sufficient flora to support honeybees or beekeeping.

Wyoming's native habitate doesn't support bees or beekeeping. There are few feral hives there. And with a few local exceptions, no bees are kept there either. But beekeeping is possible in Wyoming. When man brings the plants, the water, together with the proper climate, he can also bring his bees.

Thanks

Thanks Jan Curtis and Kate Grimes for allowing personal use of the maps shown above. For a detailed and beautiful Wyoming climate summary, check out their climate website.