The average temperature during the first 15 days of this month was 3.6 degrees. That was the coldest start to December since 2000. It also was the 10th coldest such stretch since temperature records start in 1881.
The first half of December 2000 had an average temperature of 2.9 degrees and finished with an overall average temperature of -0.2 degrees which is currently ranked as the 3rd coldest December on record. One remarkable element to that frigid December 2000 is that although ranked as 3rd coldest on record, not a single record low was set that month. Another cold December that some of you may recall occurred back in 1983. The average temperature that month was -0.3 degrees which was the 2nd coldest December on record.
Much of the cold that year arrived in the second half of the month as the first 15 days averaged 8 degrees above zero which was followed by one of the most brutal December cold snaps on record to finish the month
Yesterday in this space, I mentioned that no record lows have been set in the month of December since 1983. There are two principal reasons for this. The first is thermometer changes. Many of the records in our cold season were set in the 1880s before what is now the National Weather Service set up standards for how all temperatures should be recorded back in 1891.
For example, the low temperature has not hit -40 degrees or lower since 1891 in Fargo Moorhead. Another more significant reason why low temperatures records are more difficult to set is land use changes. As Fargo Moorhead continues to grow, our heat island, the increase in air temperature caused by man-made objects replacing the natural landscape has become more significant.
Plus, the coldest temperatures are on clear, calm nights and with the official sensor very near the airport runway, dead calm air is difficult to achieve with the increase of flights at Hector Int’l keeping the air mixed up near the official sensor.
The past 10 days have average 20 degrees below normal, yet no records have been broken. The closest we came was on Wednesday morning when the airport dropped to -18 degrees. The record low that morning happened to be the second warmest record low in December at -21 set back in 1945. We also came close to setting a record for the lowest maximum temperature on December 7 when the high was only -8 degrees locally. The record for the lowest maximum for that date is -10 degrees set back in 1882.
A fact that may surprise you is that Fargo Moorhead has not broken a record low temperature in the month of December in 30 years. The last record low temperature set this month was during the brutal cold wave that impacted much of the United States around Christmas 1983. Yet, even that cold wave produced only one record low of -31 degrees set on December 23, 1983.
The weather has certainly been cold in recent days, but locally, we have been nowhere near any record low. The record lows this time of year tend to be in the -30 to -25 degree range. One state that has set numerous record lows recently has been Oregon. An automatic temperature gauge in the Horse Ridge nature area just east of Bend, Oregon dropped to 41 degrees below zero on Sunday morning.
That same morning, the residents of Lakeview, OR, in the far south central portion of the state, woke up to a temperature of -27 degrees. Not only was that a record for the date, it was also an all-time record low for the city. That surpassed the previous coldest temperature on record of -22 set back in February 1933 and January 1937. Perhaps equally impressive was Eugene on the western side of the Cascades dropping to -10, just two degrees shy of their all-time coldest reading and Astoria, on the Pacific coast dropping all the way down to 13 degrees for a daily record low.
The average high today is 31 degrees. The average high will stay below freezing until March 8 when that average will finally be back to 32 degrees. During the three principle months of winter, December through February, Fargo Moorhead averages 18 days with a high temperature above freezing.
n four out of the last five winters, we have recorded a below average number of melting days. The one exception was during the winter of 2011-2012 when on 47 of the 91 days that winter the high temperature was above freezing. That is the most of any winter on record. Of note, the other four of the past five winters in total had only recorded 47 days above freezing, an example of how unique the winter of 2011-2012 was for warmth.
The record lowest number of winter days above freezing is two such days that occurred during the brutal winter of 1978-1979.
This is usually the time of year that we record the first below zero low temperatures of the season. It is also no coincidence that this is also the time of year when we began to record our first snowfalls of one inch or greater. Like most other climate statistics, the first below zero reading varies greatly from year to year.
The earliest below zero low temperature occurred on October 26, 1919 when the low dropped to -4 degrees. The latest first negative of the season was back in 1987 when our first negative temperature did not occur until December 31. The average date is sandwiched in between those two extremes on November 28. The average last below zero day in spring is on March 11.
The overall average number of days below zero during our cold season is 48, with ten of those days recording both a negative high and low.
October seems to be one of those months that no one really expects it to snow, yet, when no snow is actually measured, many seem to get surprised by that as well. One reason perhaps is that October snow has been fairly common in recent years. Fargo Moorhead averages just 0.7 inches in October. yet five out of the past seven years have recorded more than one inch of snow.
Historically, measurable snow has occurred in 45% of all Octobers since snow records have been kept, making these recent snowy Octobers seem more typical then it has been historically. Most years any snow this time of year is in smaller quantities as it only takes 3.8 inches to make it into the top 10 snowiest Octobers on record. Last year we came close to that finishing as the 11th snowiest when 3.6 inches were measured.
This year we tied with numerous years as the 60th snowiest October on record with just a trace being reported.
The average temperature through the first 10 months of 2013 is running about 1 degree below average. Seven of the ten months this year recorded temperatures reasonably close to the average with most of them finishing just slightly above normal. September was the only month so far this year that finished well above average. The temperature last month was 5.3 degrees above normal.
But the reason this year as a whole is running below average is because of the extremely cold March and April this region recorded. April 2013 was the coldest April on record for the state of North Dakota and ranked as the 3rd coldest in Minnesota. April finished more than 10 degrees below average in Fargo Moorhead after the month of March had also finished more than 10 degrees below normal.
Therefore, 2013 will probably finish as colder than average overall principally because of those two very cold spring months.
Our record low temperatures are now mostly in the single digits above zero and beginning in early November, all our record lows will be below zero until March 31. A couple of exceptions to that statement will be tomorrow, when the record low is -4 degrees, set in 1919, which is the earliest below zero temperature on record and one final double digit record next Wednesday when the record low is 10 degrees set in 1991.
Many of you may recall that was the day before the famed Halloween blizzard that dropped significant snow in portions of Minnesota that year. Of course, such events this time of year are rare, but smaller snow events are more common. The record lows this time of year were almost all set a day or two after a snowfall as snow cover greatly enhances our ability to cool off during our increasingly longer nights.
The first half of August finished with an average temperature of just 64.5 degrees which was 6.2 degrees below average. That ranked as the 9th coldest such period on record. It was the coolest start to August since 2004 and with the exception of 1977 all the other years with such cool starts to August were either in the 1880s or the early part of the 1900s.
Although the month started cool, unlike 2004 when a devastating frost occurred on August 20 effectively ending the growing season for most locations north of Fargo Moorhead, this month has now trended much warmer. Our current warm up looks to have staying power and therefore, by the end of the month, the average August temperature may finish very close to the average.
Not only did this month start cool, but also dry. The airport recorded only 0.25 inches of rain during the first half of the month and that ranked as the 18th driest such period on record.