Western and Central Wyoming

Weather Forecast Office

Riverton 2021 Annual Climate Summary

...Highlights of 2021...

Annual: Average temperature 3.6 degrees above normal in 2021. Precipitation was 1.02 inches below normal, or 89% of normal. Below average snowfall of 92%, and just 3.5 inches below normal.
- Average annual temperature 47.1 degrees which was the 2nd warmest year on 103 years of record (1918-2021).
- 2021 precipitation total was 8.48 inches which was the 51st driest or 53 wettest year on 103 years of record (1918-2021).
- 2021 snowfall total was 40.8 inches which was the 33rd snowiest year on 103 years of record. .
Seasonal: The 2020-2021 Seasonal Snow total was 48.2 inches, the 20th snowiest season on record.
Monthly Temperatures: 2nd warmest June, 6th warmest July, 10th warmest September, 3rd warmest November, and 2nd warmest December.
Monthly Precipitation: 5th wettest March, 7th wettest August, and tied for 3rd driest November
Monthly Snowfall: 8th snowiest March and 10th snowiest April on record.

Temperature

Precipitation

Snow

Temperature Banner

Element	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Average High	33.7	35.2	50.2	54.4	65.1	79.2	91.1	87.1	79.7	61.7	39.8	22.7	58.3
Mean High (1991-2020 Normals)	28.7	35.5	49.2	58	67.4	78.9	87.9	85.7	74.4	59.2	42.7	29.6	58.1
Average Low	8.6	9.1	20.6	27.1	39.9	47.8	56.5	54.8	46.5	31.6	15	-1.7	29.7
Mean Low (1991-2020 Normals)	4.2	9.6	22.2	30.5	40.3	48.5	54.8	52.2	42.5	30.4	17.1	5.7	29.8
Average Temperature	21.3	22.1	35.4	40.8	52.5	63.5	73.8	70.9	62.9	46.7	27.4	10.5	44.0
Mean Average Temperature (1991-2020 Normals)	16.4	22.5	35.7	44.2	53.8	63.7	71.3	69	58.4	44.8	29.9	17.6	43.9
Departure from Normal	4.9	-0.4	-0.3	-3.4	-1.3	-0.2	2.5	1.9	4.5	1.9	-2.5	-4.1	0.1
Rank: Coldest to Warmest 103 years of record (P.O.R 12/1918-2022)	81	44	63	16	34	58	92	94	100	72	38	15	61
Highest Daily Maximum	54	58	72	75	85	94	100	98	98	76	64	45	100
Date of Occurrence	13	10	27,28	22	27	18	18	11	5	21	2	2,12	7/18
Lowest Daily Minimum	-5	-14	-13	9	27	37	49	47	36	17	-11	-39	-39
Date of Occurrence	6	23	10	13	22	1,21	2	29	11	28	30	22	12/22
Number of Days with:
Maximum >= 90°	0	0	0	0	0	7	21	8	9	0	0	0	45
Maximum <= 32°	11	10	7	0	0	0	0	0	0	0	7	25	60
Minimum <= 32°	31	28	28	23	3	0	0	0	0	17	29	31	190
Minimum <= 0°	4	10	4	0	0	0	0	0	0	0	1	16	35
Record Highs Set or Tied	0	0	2	0	0	0	1	0	2	0	0	0	5
Record Lows Set or Tied	0	0	2	0	1	0	0	0	0	0	0	0	3
* Multiple day occurrence

Temperature Ranks and Records:

Daily Records:

Max:

  March: 67 on the 2nd and 75 on the 28th

July: 100 on the 18th

September: 95 on the 2nd and 98 on the 5th

Min:

  March: -20 on the 10th and -14 on the 11th

  May: 27 on the 22nd

Top Ten Warmest July's on Record
Rank	Year	Average Temperature °F
1	2006	76.2
2	2012, 2007	76.1
3	2003	75.3
4	2002	74.9
5	2021, 2001	74.8
6	2013	74.4
7	1954	74.2
8	2005	74.1
9	2022	73.8
10	2011	73.5

Top Ten Warmest August's on Record
Rank	Year	Average Temperature °F
1	2003	73.8
2	2013/2000	73.0
3	2001	72.9
4	2012	71.9
5	2020/2011	71.8
6	2007	71.6
7	1922	71.3
8	1999	71.0
9	2022/1983	70.9
10	1929	70.7

Top Ten Warmest September's on Record
Rank	Year	Average Temperature °F
1	2015	63.6
2	1998	63.5
3	1990	63.4
4	2022	62.9
5	2009, 2001	62.3
6	1938	62.2
7	1948	62.1
8	1940	62.0
9	1963	61.8
10	2021	61.6

Warmest Years on Record (100 Years)
Rank	Year	Average Temperature °F
1	2012	48.5
2	2021	47.1
3	2006, 1999	47.0
5	1934	46.9
6	2007	46.5
7	2005, 1981	46.3
9	1954	46.2
10	2015	45.9
40	2022	40.4

Top Ten Coldest Years on Record
Rank	Year	Average Temperature °F
1	1993	38.8
2	1924	39.5
3	1984, 1944	39.7
5	1978	40.1
6	1985	40.3
7	1968, 1929	40.5
9	1975	40.8
10	1986, 1932	41.0
61	2022	44.0


Average Annual Temperature for Period of Record - Click on Graph to Enlarge

Learn more about the National Weather Service's efforts to build a Weather-Ready Nation!

Precipitation Banner

Element	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Total (inches)	0.24	0.37	0.89	1.44	3.55	0.4	0.1	0.7	1.45	0.54	0.88	0.86	11.42
Mean Precipitation (1991-2020 Normals)	0.35	0.43	0.71	1.31	1.98	1.09	0.70	0.45	0.80	0.93	0.44	0.31	9.5
Departure from Normal	-0.11	-0.06	0.18	0.13	1.57	-.69	-0.6	0.25	0.65	-0.39	0.44	0.55	1.92
Percent of Normal	69	86	125	110	179	37	14	156	181	58	200	277	120
Rank - Driest to Wettest 104 years (P.O.R. 1918-2022)	63	74	87	72	89	24	15	79	91	43	90	99	90

Greatest 24-HR Total	0.18	0.22	0.21	0.54	1.19	0.31	0.05	0.25	0.54	0.25	0.26	0.50	1.19
Dates of Occurrence	6	15-16	8	23	31	1	28	25	16	24	29	13	5/31
Number of Days with:
Precipitation >= 0.01	3	5	8	8	8	5	4	9	7	9	7	4	72
Precipitation >= 0.10	1	2	5	4	7	1	0	3	4	2	4	2	35
Precipitation >= 1.00	0	0	0	0	2	0	0	0	0	0	0	0	2
Daily Precipitation Records Set or Tied	0	0	1	0	2	0	0	0	1	0	0	0	4

Precipitation Ranks and Records:

One Day Precipitation Records:

March: 0.31" on the 9th.

May: 1.16" on the 4th and 1.19" on the 31st.

September: 0.54" on the 16th.

Top Ten Wettest Months of December on Record
Rank	Year	Precipitation (inches)
1	1955	0.96
2	2016	0.93
3	1997	0.86
4	2022	0.86
5	1968	0.85
6	1982	0.79
7	1924	0.75
8	1972	0.72
9	1979	0.70
10	1985	0.68

Top Ten Driest Months of July on Record
Rank	Year	Precipitation (inches)
1	1921/1953/1957	0
2	2006	0.03
3	1943/1999	0.04
4	1945	0.05
5	1920/1932	0.07
6	1924/2011	0.08
7	1949/1996/2005/2022	0.10
8	1972	0.12
9	1929/2016	0.13
10	1964	0.14

Top Ten Driest Years on Record
Rank	Year	Precipitation (inches)
1	1988	3.75
2	2012	3.98
3	1974	4.12
4	1954	4.85
5	2001, 2006	5.07
7	2020	5.62
8	1966	5.66
9	1990	5.71
10	1922	5.91
90	2022	11.42

Top Ten Wettest Years on Record
Rank	Year	Precipitation (inches)
1	1923	18.43
2	2017	15.86
3	2016	15.24
4	1941	14.74
5	1912	14.73
6	1993	13.49
7	1998, 1995	13.41
9	1971	13.11
10	1947	12.45
15	2022	11.42


Annual Precipitation for Period of Record - Click on Graph to Enlarge

Click on Graph to Enlarge

Learn more about the National Weather Service's efforts to build a Weather-Ready Nation!

Snow Banner

Element	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Total (inches)	3.9	4.9	17.8	4.5	T	0	0	0	0	1.2	11.5	17.9	61.7
Mean Snowfall (1991-2020 Normals)	5.5	7.4	6.5	7.2	2.1	0.0	0.0	0.0	0.6	4.4	5.3	5.3	44.3
Departure from Normal	-1.6	-2.5	11.3	-2.7	-2.1	0.0	0.0	0.0	-0.6	-3.2	6.2	12.6	17.4
Percent of Normal	71	66	274	63	0	0	0	0	0	27	217	338	139
Rank - Least to Most 104 years (P.O.R 1918-2022)	58	64	96	61	72	NA	NA	NA	NA	56	91	94	102

Greatest 24-HR Total	2.7	2.1	2.7	2.3	T	0	0	0	0	1.2	3.4	9.6	9.6
Dates of Occurrence	6	16	8,16	12	13,21	0	0	0	0	24	29	22	12/22
Number of Days with:
Snowfall >= 1.0 inch	1	2	5	1	0	0	0	0	0	1	4	3	17
Daily Snowfall Records Set or Tied	0	0	1	0	0	0	0	0	0	0	0	0	1
* 69 months of May on record a trace or 0.0" of snowfall. * 83 months of September on record with no snowfall.

Snowfall Ranks and Records:

One Day Snowfall Records (inches):

March: 9.3" on the 9th.

Top Ten Snowiest March's on Record
Rank	Year	Snowfall (inches)
1	2015	22.1
2	1997	21.7
3	1967	19.5
4	1923	18.5
5	2022	17.8
6	2008	15.2
7	1972	15.0
8	1940	14.0
9	2021	11.4
10	2019, 2002, 1937	11.0

Top Ten Snowiest November's on Record
Rank	Year	Snowfall (inches)
1	1983	22.0
2	2015/1942	19.0
3	1920	17.0
4	1985	15.2
5	1978	14.8
6	1938/1919	14.0
7	1967	13.5
8	1928	13.0
9	2019	12.5
10	2022	11.5

Top Ten Snowiest December's on Record
Rank	Year	Snowfall (inches)
1	1985/1972	19.0
2	2022	17.9
3	1978	16.5
4	1979/1967	15.0
5	1968	14.5
6	2016	12.9
7	2007/1955	12.5
8	1987	12.0
9	1982	11.9
10	1924	11.7

Top Ten Snowiest Years on Record
Rank	Year	Snowfall (inches)
1	1920	77.0
2	2017	71.1
3	2013	70.6
4	2009	62.5
5	2022	61.7
5	2020	61.7
5	2016	61.7
7	2010	60.1
8	1919	58.0
9	1923	56.2
10	1944	55.4



Annual and Seasonal Snowfall for Period of Record - Click on Graph to Enlarge

Learn more about the National Weather Service's efforts to build a Weather-Ready Nation!