Overnight Temperatures in the Central Rockies

Sources

Readings before November 1997 were only taken occasionally. Since that date, I’ve almost always carried a thermometer on overnight trips.

The July 1995 reading was taken from simple REI zipper gauge bulb type thermometer.

Readings between November 1997 and June 2005 were taken with a Springfield spring-coil type thermometer.

With the exception of the November 2010 and September 2011 values (both of which were recorded on zipper gauges), readings from July 2005 to present were taken with one of three Acurite digital recording thermometers, supposedly accurate to 0.1F degrees.

Notes and Comments on Each Event

Note 1:  The above chart is for coldest camps only. I have recorded colder temperatures on day climbs.

On February 11 2006, it was at least as cold as -29°F on our climb of Nipple Peak (Elkhead Mountains, CO), but it was a day climb only. It was probably the coldest non-windchill temperature that I have climbed in. Luckily there wasn’t much wind on that particular day.

The coldest wind chill I’ve climbed in while in the Central Rockies was probably around -64°F (-93°F on the old windchill chart!) on Jacque Peak (Gore Range, CO) on December 26 2015.  There were very high winds and a temperature of -24°.  Nearby Dillon recorded -13°F and Antero Reservoir recorded a -40°F (actual temps, not windchill) during that time period.  I estimated that some of the wind gust were at least 50 mph on that day.

Note 2: Most of the above temperatures were recorded under mostly calm conditions at night, which is usually ideal for cold temperatures. The only exception is the reading from Hoosier Pass on December 11 2005. That night was the surely the windiest night I’ve ever spent while sleeping.

Notes on Specific Events

The January 14 1989 reading of -26°F at Little Brush Creek was pulled off the nearest SNOTEL site.  Since we were at the sink where Little Brush Creek enters the cave, it probably was at least that cold.  On the other hand we did sleep in a shelter which shielded us from the coldest temperatures.  The nearby town of Jensen at an elevation of only 4760 feet elevation (almost 4000 feet lower than where we were camped) recorded a -20F on that night so there is no reason to doubt the -26 reading.

The February 5 2016 reading of -20°F was recorded at Shrine Mountain during a fairly routine cold snap (Craig was -21F that same morning) and I imagine that similar temperatures are recorded there at least a few times a year.

The February 28 2021 reading of -15°F on Mt. Columbia was recorded during a routine cold snap.  The temperature in Leadville that morning was -12°F.

The March 5 1999 reading of -22°F at the East Fork Bear River is colder than normally might be expected. On calm nights, the cool air really pools into the valley bottom next to the river.

The April 7 2012 reading of 0°F near Slide Lake was highly unusual because Leadville only got down to 20°F that night. There were some weird temperature differentials going on around the state. For example, Craig at only 6200 feet elevation recorded a 9°F and many other mountain locations in the vicinity of Slide Lake were much colder than Leadville. It was a very windy night, but around Slide Lake it was calm by morning. If it was still very windy in Leadville, it could explain the huge temperature differential.

The April 18 2021 reading of 5°F at La Sal Flats was incredibly cold and unusual for the elevation.  There was a cold snap in the region, but this reading was much colder than the other official readings in the region.  Since it was in a bowl like location at the base of the mountains, perhaps it was an extreme example of a cold air sink and cold dense air descending off the mountains and into the low areas.  The thermometer was new, but seemed to be functioning properly.

The May 2 2008 reading of 10°F may seem a bit cold for the altitude, but the nearby town of Maybell recorded a reading of 11F that same night.  Cold air tends to pool along the Yampa River making it a colder location at night than many much higher elevation places in Colorado.  In fact, Maybell recorded the coldest temperature in Colorado on February 1 1985 with an incredible reading of -61°F.

The June 9 2007 reading of 13°F at the South Fork White River was another unusually cold night for 7800 feet. It was also during a record breaking cold snap the day after a snowstorm. Denver had its latest frost ever during the cold snap and several locations around Colorado had record lows on the 8th and 9th. Like the East Fork Bear River, cold air pools along the South Fork Yampa River as well.

The July 24 1995 reading of 15°F at Amethyst Lake was remarkably cold for July. In fact it was a slightly colder reading than any official weather station has recorded anywhere in Utah during July. 1995 was a heavy snow year and the area around the lake was still buried under deep snow. Amethyst Lake itself was mostly frozen over, but the adjacent shallow pond to the south was ice free in the evening. In the morning the small pond was frozen over with over an inch thick of new ice.

The August 28 2009 reading of 10°F was the most incredibly cold summer night I had ever spent and all of our water bottles froze solid. Since our elevation was lower than previous nights, I presume that the cold air sinks off the mountains and pools into this meadow. In fact, this night at least tied the coldest temperature at a camp I have ever recorded anytime between April 18 and September 5. To be fair though, the thermometer was sitting near the ground, so an official temperature would likely be a few degrees warmer.

The September 5 2021 reading of 6°F was incredibly cold for the time of year.  I set up the tent in a sink just east of Twin Lakes in the Flat Tops and at 11,030 feet.  The 6F was not recorded during a cold snap (Craig was 31F), but the place we set up the tent must have been in a cold air sink similar to Peters Sink in Utah.  The thermometer is fairly new and seemed to be working properly.

The October 7 2012 reading of -1°F was recorded during a cold snap near timberline during the thus far hot and dry year of 2012. It was 13F at the official station at Craig (6200 feet) where I live.

The November 15 1997 reading of -15°F was recorded during an early season cold snap.  The temperature in Brighton in the Wasatch that morning was -2F, but the basins in the Uinta Mountains are usually colder at night that Brighton.  This trip was my first overnight snowshoe trip.  It was actually colder when we went to bed than it was by morning.

The November 25 2010 reading of -26°F was taken during a rather severe cold snap over Thanksgiving Weekend. Even the lower valleys of Colorado recorded below zero temperatures. Craig Colorado, where I live for example, recorded a -15F at only 6200 feet elevation.

-20°F was actually the recorded value since the thermometer we had only went down to -20°F! -26°F was an estimate based on nearby weather stations and the fact that on December 26 2015, I recorded a -24°F at the same location. The readings at the nearby weather stations were about 2F colder on November 25 2010 then they were on December 26 2010, so -26F should be about right.

The December 10 2005 reading of -14°F on Hoosier Pass was the only one of these temperatures recorded in extremely windy conditions. It was extremely windy all night. It was colder in other nearby locations; in fact Denver (5280 feet) was officially -17°F and Craig (6300 feet) was officially -25°F.    

 

The December 26 2015 reading of -24°F at Guller Creek/Janets Cabin taken was under clear skies after a snowstorm.