2009 Climate Summary for Downtown Riverton

Month

Avg

High

Avg

Low

Average

Temp

Departure

From

Normal

Total

Pcpn

Departure

From

Normal

Snowfall

Avg Snow

Departure

January

35.9

9.7

22.8

7.9

0.25

-0.03

4.8

4.7

0.1

February

45.5

14.4

30.0

7.9

T

-0.25

0.1

4.3

-4.2

March

47.2

18.4

32.8

-2.1

1.15

0.67

15.2

4.4

10.8

April

56.0

31.7

43.9

-0.2

2.02

1.01

14.2

3.8

10.4

May

70.9

41.3

56.1

2.3

0.98

-0.80

0.2

0.4

-0.2

June

73.4

47.1

60.3

-3.4

1.89

0.75

0.0

T

0.0

July

86.2

53.3

69.8

-0.5

1.64

0.91

0.5

0.0

0.5

August

84.0

49.9

67.0

-1.2

0.75

0.26

0.1

0.0

0.1

September

79.1

45.5

62.3

5.0

0.30

-0.58

0.0

0.7

-0.7

October

49.2

27.2

38.2

-6.6

2.30

1.49

19.7

2.5

17.2

November

48.9

19.8

34.4

6.2

0.01

-0.46

0.2

5.0

-4.8

December

21.6

-1.4

10.1

-5.8

0.30

-0.06

7.5

5.3

2.2

Total/Ave

58.2

29.7

44.0

0.8

11.59

2.91

62.5

31.1

31.4

 

Yearly Extremes:

Highest Temperature: 97 Degrees on August 23rd
Lowest Temperature:
-28 Degrees on December 9th

Days with Maximum Temperature 90 Degrees F or Higher: 24
Days with Maximum Temperatures 32 Degrees F or Lower: 39
Days with Minimum Temperatures 32 Degrees F or Lower: 184
Days with Minimum Temperature 0 Degrees F or Lower: 26

Most Precipitation in 24 Hours: 1.34 inches on October 5-6th
Most Precipitation in One Day:
1.32 inches on October 5th
Most Snowfall in 24 Hours:
10.0 on October 5-6th 
Most Snowfall in One Day:
9.8 inches on October 5th  

Highest Wind Gust (Riverton Regional Airport): 68 mph (west-northwest) on January 11th

 
Monthly Reviews:
 

JANUARY 2009 – Much Warmer than Normal 

     Arctic Front - Downtown Riverton Plunges to -21F on the 27th

    Riverton’s average monthly temperature was 22.8 degrees which was 7.9 degrees above normal
making it the 12th warmest January on record.   Temperatures ranged from 21 degrees
below zero on the 27th  to 57 degrees on the 9th.

 

     The monthly precipitation total of 0.25 inches was 0.03 inches below normal.  Snowfall for the month
was 4.8 inches.

 

     The peak wind gust was 68 mph out of the west-northwest on the 11th.
 

FEBRUARY 2009 – Much Warmer and Drier than Normal

 

     Riverton’s average monthly temperature was 30.0 degrees which was 8.2 degrees above normal making
it the 11th warmest February on record.   Temperatures ranged from 4 degrees on the 28th to 61 degrees on the 26th.

 

     The monthly precipitation total was only a trace which was 0.25 inches below normal.
Snowfall for the month was 0.1 inches.

 

     The peak wind gust was 67 mph out of the northwest on the 25th.
 

MARCH 2009 – Cooler and Much Wetter than Normal

Warm Start - Record Highs March 2-3

March 8-10 - 5 Inches of Snow in Riverton Area

March 9-11: Cold Follows the Snow

Late March Snow Storm Dumps 4 to 7 inches of snowfall in the Riverton area.


     Riverton’s average monthly temperature was 32.8 degrees which was 2.1 degrees below normal.
Temperatures ranged from 10 degrees below zero on the 11th to 73 degrees on the 22nd.

     The monthly precipitation total of 1.15 inches was 0.67 inches above normal. 
Snowfall for the month was 15.2 inches making it the 4th snowiest March on record.

     The peak wind gust was 56 mph out of the west on the 29th.

 

APRIL 2009 –   Cooler and Drier than Normal

 

April 16-17: Spring Snow Storm Dumps 6 to 9 inches of Snow in Riverton Area

 

     Riverton’s average monthly temperature was 43.9 degrees which was 0.4 degrees below normal.
Temperatures ranged from 18 degrees on the 6th to 76 degrees on the 24th.

 

     The monthly precipitation total of 2.02 inches was 1.01 inches above normal which was the 12th

wettest April on record.  Snowfall for the month was 14.2 inches making it the 10th snowiest April on record.

 

    The peak wind gust was 59 mph out of the west on the 8th.
 

MAY 2009 – Warmer and Drier than Normal
May 24th and 25th: Over an Inch of Rain on the South Side of Riverton

     The average temperature for Riverton was 56.1 degrees which was 2.1 degrees above normal. The highest reading was 81 degrees which occurred on the 21st. The lowest reading was 19 which occurred on the 1st.

     Total precipitation for the month was 0.98 inches which was 0.80 inches below normal.

     The peak wind gust for the month and year was 64 mph out of the southwest on the 19th.

 
JUNE 2009 – Cooler and Wetter than Normal
 

     The average temperature for Riverton was 60.3 degrees which was 3.5 degrees below normal. The highest reading was 86 degrees which occurred on the 30th.   The lowest reading was 35 which occurred on the 10th. 

     Total precipitation for the month was 1.89 inches which was 0.75 inches above normal.  The greatest daily total was 0.58 inches on the 12th.  

     The peak wind gust was 63 mph out of the west on the 26th.
 
 
JULY 2009 – Slightly Cooler and Much Wetter than Normal
 

    The average temperature for Riverton was 69.8 degrees which was 0.6 degrees below normal.
The highest reading was 95 degrees which occurred on the 23rd. The lowest reading was 39 which occurred on the 16th.

     Total precipitation for the month was 1.64 which was 0.91 Inches above normal making it the 13th wettest on record.  The greatest daily total was 1.10 inches on the 5th.  

     The highest wind gust was 66 mph out of the northwest which occurred on the 21st.

 
 
AUGUST 2009 – Cooler and Slightly Wetter than Normal
 
August 16th-17th: Where Did Summer Go?
    
     Riverton’s average temperature for the month was 67.0 degrees which was 1.5 degrees below normal.
The highest temperature for the month and year was 97 degrees on the 23rd.  The lowest temperature was
39 on the 17th  
 
     Total precipitation for the month was 0.75 inches which was 0.26 inches above normal.
The day with the greatest rainfall was 0.47 inches on the 16th.
 
     The peak wind gust was 56 mph out of the north on the 3rd.
 
 
SEPTEMBER 2009 – Much Warmer and Drier than Normal
 

     The average temperature for Riverton was 62.3 degrees which was 4.9 degrees above normal. The highest reading was 89 degrees which occurred on the 5th.  The lowest reading was 30 which occurred on the 28th.

     Total precipitation for the month was a 0.30 inches which was 0.58 inches below normal.  

     The peak wind gust was 59 mph out of the north on the 20th.
 
 
OCTOBER 2009 – 3rd Coldest and 4th Snowiest on Record

    Coldest First 17 Days in Riverton Weather History

 

     The average temperature for Riverton was 38.2 degrees which was 6.7 degrees below normal which ties it with 1969 for the 3rd coldest October on record. The highest reading was 70 degrees which occurred on the 20th.  The lowest reading was 6 degrees on the 10th  which shattered the old record by seven degrees. The record low of 6 degrees was also the coldest temperature  ever recorded so early in the season and only the second single digit low temperature ever recorded before October 20th

         Total precipitation for the month was a 2.30 of an inch which was 1.49 inches above normal making it the 7th
wettest October on record. The greatest daily precipitation was 1.32 inches on the 5th. There was 19.7 inches of snowfall during the month with 10 inches of snow falling during the early season storm on the 5th and 6th.  The 19.7 inches of snow in October made it the 4th snowiest October on record dating back to 1907.

     The peak wind gust was 55 mph out of the northwest on the 24th.

 
 
 
NOVEMBER 2009 – Much Warmer than Normal with only 0.01 inches of Precipitation
 
    The average temperature for Riverton was 34.4 degrees which was 6.3 degrees above normal.  
The highest reading was 67 degrees which occurred on the 7th. The lowest reading was 10 which occurred on the 15th.   
 

     Total precipitation for the month was a 0.01 inches which was 0.46 inches below normal.  There was only 0.2 inches of snowfall during the entire month.

 

     The peak wind gust was 56 mph out of the southwest northwest on the 11th.
 
 
DECEMBER 2009 – Much Colder with Near Normal Precipitation

 

     The average temperature for Riverton was 10.1 degrees which was 5.8 degrees below normal. The highest reading was 50 degrees which occurred on the 22nd. The lowest reading was 28 below zero which occurred on the 9th.

 

     Total precipitation for the month was a 0.30 inches which was 0.06 inches below normal.  The greatest daily precipitation was 0.07 of an inch that fell on the 24th. There were 7.5 inches of snowfall

during the month which was 2.2 inches above normal.

 

     The highest wind gust of the month was 61 mph out of the northwest which occurred on the 9th.
 
 

 


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