On Feb. 1, 1985, the temperature at Peter Sinks location plummeted to -69.3°F, the second coldest ever recorded in the lower 48 states.
The lowest was -69.7°F at Roger's Pass, Montana in January 1954. Moreover, Peter Sinks and nearby Middle Sink have the distinction of having
all but one of the monthly low temperature records for Utah.
So why is this montane site, located 20 miles northeast of Logan, so cold? The low temperatures are due to a combination of the area’s unique basin topography,
high elevation, and dry climate. Peter Sinks, at an elevation of 8,164 feet, is a natural limestone sinkhole approximately one-half mile in diameter;
one can liken it to a large bowl, which has no valley outlet to drain water or air. On calm cloudless nights this high basin loses accumulated daytime heat to the atmosphere.
In addition, cool dense air slides down-slope into the basin floor in a process known as cold air pooling. Extremely low temperatures can occur, especially in the
wake of wintertime arctic fronts.
This monitoring page contains data from a station in the sink and one on the rim. The station on the rim provides a point of comparison to make it easier to see how
temperatures in the sink relate to the surrounding area.
