-14F at Larson Creek (Elkhead Mountains) at 8100 feet on February 2 2013 is the coldest tent campsite for February. The -20F was taken on February 6 2016 at Chucks Cabin at Shrine Mountain.
9F at Montezuma Basin (Elk Mountains) at 11,430 feet on April 16 2006 is the coldest tent campsite for April. The 0F was taken on April 7 2012 at the 10th Mountain Division Hut near Slide Lake.
-15F was taken at Yellow Pine Creek (Uinta Mountains) at 9330 feet in 1997 and is the coldest tent campsite for November. The -26F was taken on November 25 2010, at Janets Cabin in Union Creek Basin.
-14F was taken at Hoosier Pass (Mosquito Range) at 11540 feet in 2005 and is the coldest tent campsite for December. The -24F was taken on December 26 2015, at Janets Cabin in the Union Creek Basin.
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 Some Selected Events
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 -29F 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 -54F (-77F on the old windchill chart!) on Northstar Mountain (Mosquito Range, CO) on December 9 2005.
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.
3. The March 5 1999 reading of -22F 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.
4. The April 7 2012 reading of 0F near Slide Lake was highly unusual because Leadville only got down to 20F that night. There were some weird temperature differentials going on around the state. For example, Craig at only 6200 feet elevation recorded a 9F 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.
5.The June 9 2007 reading of 13F 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.
6.The July 24 1995 reading of 15F 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.
7. The August 28 2009 reading of 10F was the most incredibly cold summer night I had ever spen 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 17 and October 6. To be fair though, the thermometer was sitting on the ground, so an official temperature would likely be a few degrees warmer.
8. The September 4 2011 reading of 10F was taken by another party camped at Mistymoon Lake. All of our water bottles froze, but I did not bring my thermometer on this trip.
I have also recorded a 10F reading on September 30 2005 at Ashley Twin Lakes in the Uinta Mountains of Utah.
9.The October 7 2012 reading of -1F 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.
10. The November 25 2010 reading of -26F 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.
-20F was actually the recorded value since the thermometer we had only went down to -20F! -26F was an estimate based on nearby weather stations and the fact that on December 26 2015, I recorded a -24F 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.
11. The December 10 2005 reading of -14F 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 -17F and Craig (6300 feet) was officially -25F.
12. The December 26 2015 reading of -24F at Guller Creek/Janets Cabin taken was under clear skies after a snowstorm.