SIOUX CITY AREA
CLIMATIC SUMMARY
2008

By Richard Ryrholm
Climatic Focal Point
National Weather Service, Sioux Falls

...2008 BELOW NORMAL IN TEMPERATURE FOR THE FIRST TIME IN OVER 10 YEARS...

Temperatures averaged 46.3 degrees for 2008, or 2.0 degrees below the normal of 48.3 degrees. This was the first year since 1997 that has averaged below normal, and tied 1924 for the 9th coolest year on record. All months were below normal in temperature in 2008 except the fall months of September, October, and November. It was another wet year in Siouxland in 2008, totaling 31.64 inches at the Sioux Gateway Airport, or 5.65 inches above normal. Out of the past 18 years, only 5 years (or 28%) had below normal precipitation, and the 18 year average of 28.10 inches was about 2 inches above the official 30 year normal of 25.99 inches. Snowfall for the 2007-08 season was 43.8 inches or 12.4 inches above normal, with 37.1 inches of this occurring from December to February. The following is a chronological account of the weather events of 2008 in Siouxland...

January 20-21st … There was a total of 9.7 inches snowfall, or 8.0 inches within a 24 hour period for the second biggest snowfall of the year.

January 24th … The minimum temperature of 20 below zero was the lowest temperature of 2008, with 19 below zero on December 22nd late in the year a close second.

January 29th … Strong northwest winds gusted to 55 mph at 625 AM, ushering in much colder air for the day. Wind chills dropped to 25 below zero at 11 AM for the coldest daytime wind chills since the previous January.

February 20th … The lowest wind chill of the winter season of 33 below zero was recorded at 4 to 5 AM in the morning.

March 27th … 3.6 inches of snow was measured, for the last snowfall of the season over a half inch.

April 10-11th … 1.84 inches of rain was recorded, for the first heavy rain event of the year.

April 15th … It was a warm and very windy day with south winds gusting as high as 55 mph at 432 PM CDT.

May 29th … Thunderstorms produced 1.52 inches of rain, and south winds gusted to 56 mph at 802 PM CDT. May ended up with a total of 5.20 inches precipitation, for the wettest month of the year.

June 4-5th … Thunderstorms brought strong winds, hail, and an airport total of 1.18 inches rain. Winds gusted to 56 mph at 1045 PM CDT late on the 4th , and hail up to one inch in diameter fell in the area around 1230 PM CDT in the early afternoon of the 5th .

July 6th … Heavy rain from thunderstorms caused flash flooding of several streets in the Indian Hills area of Sioux City around 6 PM CDT. However, only 0.50 inch of rain occurred at the Sioux City Airport.

July 19-21st … Severe weather struck the area, and rainfall totaled 2.66 inches in three days at the airport. Between 7 and 730 PM CDT on the 19th, hail up to an inch in diameter with wind gusts around 60 mph were reported in the area. Then very early on the 21st between 1230 and 100 AM CDT severe thunderstorms caused widespread damage in and near Sioux City. Tree damage included large trees blown down, blocking several roads. A few vehicles were destroyed and numerous vehicles damaged by falling trees and tree debris. Falling trees also damaged several residences and garages, causing one known injury. Numerous buildings, especially residences, sustained roof and shingle damage. Power lines and poles were blown down or broken, leaving an estimated 19,000 customers without power. Officially at the airport, 74 mph winds were recorded at 1239 AM for the strongest wind of the year.

August 3rd … The daily maximum of 96 degrees was the hottest temperature of 2008. However, this was only the 4th, and also the last, 90 degree (or greater) day of the year. This year ties 1915 for the second least number of days of 90 degrees plus. 1915 also had the coldest summer on record. The least number of 90 plus days on record was only three in 1992, which also was the 2nd coldest summer on record. The normal number of 90 degree plus days a year is 25 for Sioux City.

August 27-28th … Thunderstorms produced 1.77 inches of rain within a 24 hour period at the airport.

October 22-23rd … Heavy rain brought 2.53 inches of rain within a 24 hour period for the heaviest official precipitation event of the year. October ended up with 4.61 inches precipitation, for the 5th wettest October on record.

October 26th … A strong northwest wind gust of 56 mph was recorded at the airport at 936 AM CDT.

November 3rd … The daily high of 80 degrees was just one degree short of the record high for the date.

December 16-19th … 5.3 inches snowfall on the 16th was followed by 10.3 inches snowfall within 24 hours on the 18-19th, for the biggest snowfall of the year. This made a snow depth of 16 inches at the Sioux City Airport. The total December snowfall of 22.6 inches was the second snowiest December on record, compared to the record of 26.4 inches in 1897.

THE FOLLOWING TABLES GIVE A MONTH BY MONTH BREAKDOWN OF WEATHER IN 2008 AT THE SIOUX CITY AIRPORT...

TEMPERATURES

AVERAGE             DEPARTURE  EXTREMES    MONTHLY
MONTH MAX MIN MONTHLY FROM NORM HIGH LOW RECORDS

JANUARY 25.5 5.4 15.5 MINUS 3.1 46 20B
FEBRUARY 27.9 8.0 17.9 MINUS 7.2 45 13B
MARCH 42.9 23.3 33.1 MINUS 3.4 60 5B
APRIL 57.6 34.0 45.8 MINUS 3.7 79 20
MAY 70.8 46.1 58.5 MINUS 2.7 86 33
JUNE 81.8 57.1 69.4 MINUS 1.1 90 48
JULY 85.5 63.6 74.5 MINUS 0.1 92 52
AUGUST 83.8 59.5 71.6 MINUS 0.5 96 49
SEPTEMBER 76.3 51.0 63.7 PLUS 0.6 88 38
OCTOBER 64.6 39.2 51.9 PLUS 1.1 81 20 5TH WETTEST
NOVEMBER 46.6 26.2 36.4 PLUS 1.6 80 5
DECEMBER 28.3 5.6 17.0 MINUS 5.3 54 19B 2ND SNOWIEST

2008 57.6 34.9 46.3 MINUS 2.0 96 20B

NORMAL YEAR 59.5 37.0 48.3

PRECIPITATION (INCHES) AND WINDS

DEPARTURE            DEPARTURE   MAX WIND GUSTS...
MONTH FROM NORM SNOWFALL FROM NORM DIRECTION/MPH/DATE

JANUARY .73 PLUS .14 14.5 PLUS 8.2 NW 55 ON 29TH
FEBRUARY .81 PLUS .19 10.4 PLUS 4.9 NW 47 ON 9TH
MARCH 1.23 MINUS .77 6.0 PLUS 0.2 NW 48 ON 12TH
APRIL 2.79 PLUS .04 0.7 MINUS 1.2 S 55 ON 15TH
MAY 5.20 PLUS 1.45 0 S 56 ON 29TH
JUNE 3.35 MINUS .26 0 NE 56 ON 4TH
JULY 4.39 PLUS 1.09 0 N 74 ON 20TH
AUGUST 2.67 MINUS .23 0 N 39 ON 12TH
SEPTEMBER 3.34 PLUS .92 0 N 38 ON 14TH
OCTOBER 4.61 PLUS 2.62 0 MINUS 0.8 NW 56 ON 26TH
NOVEMBER 1.06 MINUS .34 2.9 MINUS 1.9 NW 41 ON 14TH
DECEMBER 1.46 PLUS .80 22.6 PLUS 16.3 NW 54 ON 14TH

2008 31.64 PLUS 5.65 57.1 PLUS 25.7 N 74 JUL 20TH

RICHARD S. RYRHOLM...CLIMATIC FOCAL POINT

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.