Teton Mountain Range

Technical Resources

Appendix 8b

Average monthly Class A pan and lake evaporation values for various stations in Wyoming

Reference: Martner, Brooks E. 1986, Wyoming Climate Atlas. University of Nebraska Press, Lincoln, NE 432pp., Table 12.1. Note: A factor of 0.70 was used to convert the pan evaporation data shown in this reference to lake evaporation amounts shown in the table below.

**Anchor Dam**
Month	Mean Monthly Class A Pan Evaporation (inches)	Mean Monthly Class A Lake Evaporation (inches)
Jan	-	-
Feb	-	-
Mar	-	-
Apr	-	-
May	7.10	4.97
Jun	8.53	5.97
Jul	9.67	6.77
Aug	8.46	5.92
Sept	6.07	4.25
Oct	-	-
Nov	-	-
Dec	-	-
Total	-	-

**Anchor Experiment Station**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	-	-
Feb	-	-
Mar	-	-
APR	-	-
May	3.40	2.38
Jun	7.52	5.26
Jul	8.66	6.06
Aug	8.31	5.82
Sept	6.20	4.34
Oct	-	-
Nov	-	-
Dec	-	-
Total	-	-

**Boysen Dam**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	-	-
Feb	-	-
Mar	-	-
APR	-	-
May	7.38	5.17
Jun	8.69	6.08
Jul	10.53	7.37
Aug	9.50	6.65
Sept	6.23	4.36
Oct	3.27	2.29
Nov	-	-
Dec	-	-
Total	-	-

**Farson**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	-	-
Feb	-	-
Mar	-	-
APR	-	-
May	7.91	5.54
Jun	9.75	6.83
Jul	11.00	7.70
Aug	9.12	6.38
Sept	6.76	4.73
Oct	-	-
Nov	-	-
Dec	-	-
Total	-	-

**Gillette**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	-	-
Feb	-	-
Mar	-	-
APR	4.61	3.23
May	6.78	4.75
Jun	7.72	5.40
Jul	9.75	6.83
Aug	9.69	6.76
Sept	6.35	4.45
Oct	2.16	1.51
Nov	-	-
Dec	-	-
Total	-	-

**Green River**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	-	-
Feb	-	-
Mar	-	-
APR	-	-
May	9.14	6.40
Jun	10.22	7.15
Jul	12.22	8.55
Aug	20.53	14.37
Sept	7.36	5.15
Oct	-	-
Nov	-	-
Dec	-	-
Total	-	-

**Heart Mountain**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	-	-
Feb	-	-
Mar	-	-
APR	-	-
May	6.55	4.59
Jun	7.18	5.03
Jul	8.43	5.90
Aug	7.45	5.22
Sept	5.10	3.57
Oct	3.79	2.65
Nov	-	-
Dec	-	-
Total	-	-

**Laramie 2NW**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	-	-
Feb	-	-
Mar	-	-
APR	-	-
May	8.96	6.27
Jun	10.23	7.16
Jul	11.02	7.71
Aug	9.73	6.81
Sept	7.65	5.36
Oct	-	-
Nov	-	-
Dec	-	-
Total	-	-

**Morton 1NW**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	-	-
Feb	-	-
Mar	-	-
APR	-	-
May	6.10	4.27
Jun	7.07	4.95
Jul	9.88	6.92
Aug	7.57	5.30
Sept	5.17	3.62
Oct	-	-
Nov	-	-
Dec	-	-
Total	-	-

**Pathfinder Dam**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	-	-
Feb	-	-
Mar	-	-
APR	5.45	3.82
May	6.94	4.86
Jun	8.62	6.03
Jul	10.54	7.38
Aug	9.69	6.78
Sept	7.33	5.13
Oct	5.44	3.81
Nov	-	-
Dec	-	-
Total	-	-

**Sheridan Field Station**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	-	-
Feb	-	-
Mar	-	-
APR	-	-
May	6.21	4.35
Jun	7.67	5.37
Jul	9.82	6.87
Aug	9.44	6.61
Sept	6.29	4.40
Oct	-	-
Nov	-	-
Dec	-	-
Total	-	-

**Whalen Dam**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	-	-
Feb	-	-
Mar	-	-
APR	5.99	4.19
May	7.85	5.50
Jun	9.06	6.34
Jul	10.63	7.44
Aug	9.53	6.67
Sept	6.61	4.63
Oct	4.81	3.37
Nov	-	-
Dec	-	-
Total	-	-

**Casper WSO**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	1.85	1.30
Feb	1.92	1.34
Mar	3.03	2.12
APR	4.73	3.31
May	6.92	4.84
Jun	8.76	6.13
Jul	10.64	7.45
Aug	9.85	6.90
Sept	6.65	4.66
Oct	5.18	3.63
Nov	2.38	1.67
Dec	1.82	1.27
Total	63.73	44.61

**Cheyenne WSO**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	2.42	1.69
Feb	2.41	1.69
Mar	3.32	2.32
APR	5.26	3.68
May	7.01	4.91
Jun	8.16	5.71
Jul	9.23	6.46
Aug	8.61	6.03
Sept	6.18	4.33
Oct	4.77	3.34
Nov	2.95	2.07
Dec	2.51	1.76
Total	62.83	43.98

**Lander WSO**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	1.09	0.76
Feb	1.51	1.06
Mar	2.84	1.99
APR	4.25	2.98
May	6.42	4.49
Jun	7.98	5.59
Jul	9.87	6.91
Aug	9.05	6.34
Sept	5.63	3.94
Oct	3.55	2.49
Nov	1.53	1.07
Dec	1.11	0.78
Total	54.83	38.38

**Sheridan WSO**
Month	Mean Monthly Class A Pan Evap. (Inches)	Mean Monthly Class A Lake Evap. (Inches)
Jan	0.96	0.67
Feb	1.11	0.78
Mar	2.33	1.63
APR	3.96	2.77
May	5.56	3.89
Jun	6.56	4.59
Jul	8.64	6.05
Aug	7.86	5.50
Sept	4.59	3.21
Oct	3.27	2.29
Nov	1.52	1.06
Dec	1.16	0.81
Total	47.52	33.26

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