Flagstaff, Arizona is located at an elevation of around 7000 feet. Because of this fact, temperatures
in the winter can be much colder than what most people would expect in Arizona. In fact, some people
can be caught without the proper clothing when visiting Flagstaff in the winter, bringing short sleeved shirts and shorts, rather
than a thick coat and gloves. Flagstaff's elevation
of 7000 feet assures a variety of weather including cool winters and mild pleasant summers, with considerable
diurnal temperature changes (the difference between daily maximum and minimum temperatures). So, how cold
does it actually get in Flagstaff?
Weather records have been taken in Flagstaff since September 9, 1898. Therefore, we
have about 100 years of weather records to look back at to see what a 'typical' winter in Flagstaff is like.
The average high temperature in Flagstaff during the month of January is 42.2oF, but the average low
temperature is a cold 15.2oF. Temperatures can dip down into the single digits and even below zero
during some of the long winter nights.
How many days per year does Flagstaff reach 32 degrees at night?
On 267 nights of the year, the temperature will reach at least 40 degrees or
cooler (which is almost 75% of the nights). On average, Flagstaff will have overnight low temperatures of 32 degrees
or lower, 210 nights out the year (which is almost 60% of the nights). Even more surprising
to many people who do not live in Flagstaff is that on average, Flagstaff will reach zero or colder
eight nights out of the year! Who would have thought anywhere in Arizona could get below zero?
Does Flagstaff ever get extended cold snaps?
Flagstaff can have extended periods of cold weather (although not cold by Midwest standards!).
Even the summers are cool, with a growing season of only 103 days on average. The average date of the last
frost is June 13, and the average date of the first frost is September 21. In 1968, the growing season
was only 73 days!!
The longest stretch of consecutive days where the temperature
fell to zero or below was 8 days set between December 27, 1966 - January 3, 1967 which tied the previous record
established between
December 31, 1918 - January 7, 1919. The most recent cold snap occurred between December 22 - December 27, 1990
when the mercury fell to zero or below on 6 consecutive nights.
The maximum number of days in a calender year with minimum temperatures of zero degrees or lower was 23 set in 1932.
The maximum number of days in any month with minimum temperatures of zero degrees or lower were the 17 days that occurred
in the extremely cold month of January 1937.
So what is the coldest temperature ever recorded in Flagstaff?
So, when did the coldest temperature occur in Flagstaff? If you guessed 1937,
you'd be right! The exact date was January 22, 1937 when the mercury fell to a mind-numbing
-30 degrees. Thats right, 30 degrees BELOW zero!! Even with that cold of an overnight temperature, the afternoon
high temperature that day was +12 degrees, a full 42 degrees warmer than the night time low. That's a big diurnal change!
How can I find out more about the climate of Flagstaff?
There is a lot of information on the internet regarding climate, and even the climate of Flagstaff. The links provided below will take you
to some of these climate pages, including the climate page on the Flagstaff National Weather Service Office. A link is provided
to the Australian Government page showing actual observations from Antarctica, just in case you really want to see
what cold is (Remember that their winter occurs during our summer).
www.weather.gov 
