Pond Evaporation Calculation													1/31/22
Weather Station Data provided by Northern Colorado Water Conservancy District
See Weather Station Location Map at:
http://www.northernwater.org/WaterConservation/WeatherandETData.aspx
Notes:
Current month reflects values through "Reference Date".
Pond Evap. calculated per recent Division 1 Water Court decree language:							Lower South Platte Home Page
Gross Pond = .84(Alfalfa ETr)							Pond Evaporation Reports Main Menu
Net Pond = .84(Alfalfa ETr) - .7(Total Precip)
Alfalfa reference ETr computed by Standard ASCE equation from daily weather data.
Winter pond evap. is a reference for unfrozen ponds.
For Growing Degree Days:
Tmax = 86° F, Tmin = 50° F and Tbase = 50° F
														Totals
Weather Station	2021	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	or Avg.
Ovid	Avg. Temp ° F	28.9	18.32	40.2	46.02	56.74	72.16	75.61	72.96	65.54	50.09	40.32	31.75	49.88
Ref date as of 12/31/2021	Total Precip "	0.17	0.41	2.88	1.46	3.68	1.3	0.28	3.83	2.13	0.66	0.34	0.22	17.36
Site Type: Alfalfa	Total Alfalfa ETr "	1.95	1.69	4.27	5.98	5.8	8.87	9.13	7.78	6.02	4.51	3.05	2.48	61.53
Total Growing Degee Days from March 1		0	0	129	209	305	604	705	664	505	290	165	84	3660
Gross Pond Evap	Total "	1.64	1.42	3.59	5.02	4.87	7.45	7.67	6.54	5.06	3.79	2.56	2.08	51.69
Net Pond Evap	Total "	1.52	1.13	1.57	4	2.3	6.54	7.47	3.85	3.57	3.33	2.32	1.93	39.53
Crook	Avg. Temp ° F	29.97	19.51	40.01	45.89	56.96	71.52	75.09	71.96	64.94	50.4	40.94	31.2	49.87
Ref date as of 12/31/2021	Total Precip "	0.1	0.42	2.64	1.91	5.13	2.5	1.97	3.92	0.38	0.99	0.17	0.09	20.22
Site Type: Alfalfa	Total Alfalfa ETr "	2.06	1.83	4.19	5.9	5.71	8.48	8.44	7.39	6.22	4.62	3.25	2.51	60.6
Total Growing Degee Days from March 1		0	0	128	212	310	585	694	640	498	301	179	86	3633
Gross Pond Evap	Inch	1.73	1.54	3.52	4.96	4.8	7.12	7.09	6.21	5.22	3.88	2.73	2.11	50.91
Net Pond Evap	Inch	1.66	1.24	1.67	3.62	1.21	5.37	5.71	3.46	4.96	3.19	2.61	2.05	36.75
Sterling	Avg. Temp ° F	29.56	20.74	38.85	45.11	56.36	71.34	75.65	73.66	65.74	50.77	41.78	31.86	50.12
Ref date as of 12/31/2021	Total Precip "	0.15	0.33	2.35	2.83	4.46	2.58	0.71	0.68	0.39	0.45	0.1	0.09	15.12
Site Type: Alfalfa	Total Alfalfa ETr "	1.87	1.94	3.96	5.46	5.5	8.75	8.17	8.15	6.32	4.44	2.98	2.26	59.8
Total Growing Degee Days from March 1		0	0	115	199	297	571	698	655	497	313	184	101	3630
Gross Pond Evap	Inch	1.57	1.63	3.33	4.59	4.62	7.35	6.86	6.85	5.31	3.73	2.5	1.9	50.24
Net Pond Evap	Inch	1.47	1.4	1.68	2.61	1.5	5.54	6.37	6.37	5.04	3.41	2.43	1.84	39.66
Brush	Avg. Temp ° F	29.16	22.58	38.11	44.87	56.31	69.76	73.85	71.39	63.31	49.05	39.7	29.63	48.98
Ref date as of 12/31/2021	Total Precip "	0.28	0.47	2.27	2.63	3.33	0.6	2.51	0.75	0.49	0.34	0.09	0.13	13.89
Site Type: Alfalfa	Total Alfalfa ETr "	1.83	1.92	3.96	5.53	5.65	8.09	8.28	7.25	5.89	4.56	2.75	2.31	58.02
Total Growing Degee Days from March 1		0	0	112	212	317	555	677	622	484	309	183	116	3587
Gross Pond Evap	Inch	1.54	1.61	3.33	4.65	4.75	6.8	6.96	6.09	4.95	3.83	2.31	1.94	48.76
Net Pond Evap	Inch	1.34	1.28	1.74	2.8	2.42	6.38	5.2	5.57	4.6	3.59	2.25	1.85	39.02
Fort Morgan	Avg. Temp ° F	29.27	22.24	38.57	45.49	56.91	71.42	74.93	72.62	64.99	50.3	40.75	30.91	49.87
Ref date as of 12/31/2021	Total Precip "	0.17	0.35	1.86	2.25	3.33	1.29	3.81	0.65	0.32	0.38	0.08	0.03	14.52
Site Type: Turf	Total Alfalfa ETr "	1.75	1.84	3.72	5.32	5.66	8.3	8.54	7.77	6.15	4.3	2.59	2.07	58.01
Total Growing Degee Days from March 1		0	0	112	205	320	572	698	637	498	309	171	83	3605
Gross Pond Evap	Inch	1.47	1.55	3.12	4.47	4.75	6.97	7.17	6.53	5.17	3.61	2.18	1.74	48.73
Net Pond Evap	Inch	1.35	1.3	1.82	2.89	2.42	6.07	4.51	6.07	4.94	3.35	2.12	1.72	38.56
Wiggins	Avg. Temp ° F	28.85	22.05	37.68	44.73	55.72	71.31	73.75	71.15	63.81	49.04	39.28	29.57	48.91
Ref date as of 12/31/2021	Total Precip "	0.15	0.34	1.39	1.48	2.52	0.85	2.12	1.37	0.24	0.18	0.04	0.05	10.73
Site Type: Alfalfa	Total Alfalfa ETr "	1.82	1.96	3.9	5.54	5.9	9.66	8.73	7.59	6.31	4.63	2.66	2.23	60.93
Total Growing Degee Days from March 1		0	0	108	197	299	568	678	608	488	317	167	83	3513
Gross Pond Evap	Inch	1.53	1.65	3.28	4.65	4.96	8.11	7.33	6.38	5.3	3.89	2.23	1.87	51.18
Net Pond Evap	Inch	1.42	1.41	2.3	3.62	3.19	7.52	5.85	5.42	5.13	3.76	2.21	1.84	43.67
Fort Collins East	Avg. Temp ° F	29.21	23.2	37.05	44.62	54.78	70.12	72.07	69.18	62.59	49.94	42.27	33.34	49.03
Ref date as of 12/31/2021	Total Precip "	0.28	0.54	16.81	1.25	3.48	0.35	0.84	0.55	0.27	0.16	0.38	0.34	25.25
Site Type: Alfalfa	Total Alfalfa ETr "	1.86	2.13	3.47	5.27	5.37	8.22	7.73	7.71	6.46	4.63	3.15	2.69	58.69
Total Growing Degee Days from March 1		0	0	80	191	286	539	631	566	470	274	158	75	3270
Gross Pond Evap	Inch	1.56	1.79	2.91	4.43	4.51	6.9	6.49	6.48	5.43	3.89	2.65	2.26	49.3
Net Pond Evap	Inch	1.37	1.41	0	3.55	2.07	6.66	5.91	6.09	5.24	3.78	2.38	2.02	40.48
Eaton	Avg. Temp ° F	29.22	22.31	36.69	44.64	54.81	70.24	71.94	69.32	62.8	49.34	41.68	32.57	48.8
Ref date as of 12/31/2021	Total Precip "	0.21	0.41	1.35	1.83	2.37	1.54	0.6	0.36	0.36	0.25	0.38	0.42	10.08
Site Type: Alfalfa	Total Alfalfa ETr "	1.86	2.04	3.55	5.44	5.74	8.73	7.39	7.06	6.28	4.43	2.83	2.55	57.9
Total Growing Degee Days from March 1		0	0	85	193	295	534	638	585	473	282	154	71	3310
Gross Pond Evap	Inch	1.56	1.71	2.98	4.57	4.82	7.33	6.21	5.93	5.28	3.72	2.38	2.14	48.63
Net Pond Evap	Inch	1.42	1.43	2.04	3.29	3.16	6.26	5.79	5.68	5.02	3.55	2.11	1.85	41.6
Johnsons Corner	Avg. Temp ° F	30.98	24.12	38.46	46.08	54.6	70.51	74.42	72.66	66.66	51.99	44.82	36.95	51.02
Ref date as of 12/31/2021	Total Precip "	0.48	0.62	1.41	1.38	4.32	0.57	0.6	0.54	0.48	0.2	0.15	0.58	11.33
Site Type: Alfalfa	Total Alfalfa ETr "	1.86	2.07	3.53	5.25	4.86	8.11	8.45	8.21	6.77	4.45	3.04	2.84	59.44
Total Growing Degee Days from March 1		0	0	77	178	262	563	702	651	500	263	161	81	3438
Gross Pond Evap	Inch	1.56	1.74	2.97	4.41	4.08	6.81	7.1	6.9	5.69	3.74	2.55	2.39	49.94
Net Pond Evap	Inch	1.23	1.3	1.98	3.44	1.06	6.41	6.68	6.52	5.35	3.6	2.45	1.98	42
Gilcrest	Avg. Temp ° F	27.39	22.9	36.66	44.91	54.7	70.57	73.38	70.68	62.96	49.12	40.59	32.75	48.88
Ref date as of 12/31/2021	Total Precip "	0.34	0.4	1.51	1.02	3.29	0.94	1.38	0.68	1.42	0.67	0.13	0.33	12.11
Site Type: Alfalfa	Total Alfalfa ETr "	1.62	1.92	3.52	5.28	5.26	8.96	8.52	7.86	5.94	4.36	2.68	2.6	58.52
Total Growing Degee Days from March 1		0	0	84	198	281	554	666	599	469	273	162	83	3369
Gross Pond Evap	Inch	1.36	1.61	2.96	4.44	4.42	7.53	7.16	6.6	4.99	3.66	2.25	2.18	49.16
Net Pond Evap	Inch	1.12	1.33	1.9	3.72	2.12	6.87	6.19	6.13	4	3.19	2.16	1.95	40.68
Longmont South	Avg. Temp ° F	30.59	24.39	38.1	45.07	53.82	69.26	73.45	71.85	64.8	50.67	45.53	37.47	50.42
Ref date as of 12/31/2021	Total Precip "	0.44	0.66	1.63	1.95	4.51	0.71	0.94	1.05	0.31	0.16	0.2	0.45	13.01
Site Type: Alfalfa	Total Alfalfa ETr "	2.04	2.29	3.48	5.03	4.98	8.22	8.16	6.72	6.03	4.16	3.38	3.02	57.51
Total Growing Degee Days from March 1		0	0	80	179	253	520	658	616	478	268	184	102	3338
Gross Pond Evap	Inch	1.71	1.92	2.92	4.23	4.18	6.9	6.85	5.64	5.07	3.49	2.84	2.54	48.29
Net Pond Evap	Inch	1.41	1.46	1.78	2.86	1.03	6.41	6.2	4.91	4.85	3.38	2.7	2.22	39.21
Fort Collins NW	Avg. Temp ° F	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Ref date as of 12/31/2010	Total Precip "	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Site Type: Turf	Total Alfalfa ETr "	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Total Growing Degee Days from March 1		0	0	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Gross Pond Evap	Inch	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Net Pond Evap	Inch	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Fort Collins Central	Avg. Temp ° F	29.74	24.12	37.71	45.2	54.79	69.93	73.22	70.19	63.2	48.76	42.25	33.71	49.4
Ref date as of 12/31/2021	Total Precip "	0.27	0.5	1.39	1.85	4.91	0.44	0.68	0.66	0.61	0.24	0.14	0.06	11.75
Site Type: Turf	Total Alfalfa ETr "	1.81	2.07	3.37	4.88	5.15	7.47	7.21	6.83	5.65	3.58	2.57	2.2	52.79
Total Growing Degee Days from March 1		0	0	85	179	282	528	644	576	471	254	153	68	3240
Gross Pond Evap	Inch	1.52	1.74	2.83	4.1	4.33	6.27	6.06	5.74	4.75	3.01	2.16	1.85	44.36
Net Pond Evap	Inch	1.33	1.39	1.86	2.8	0.89	5.97	5.58	5.28	4.32	2.84	2.06	1.81	36.13
Windsor	Avg. Temp ° F	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Ref date as of 7/1/2012	Total Precip "	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Site Type: Dryland Pasture	Total Alfalfa ETr "	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Total Growing Degee Days from March 1		0	0	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Gross Pond Evap	Inch	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Net Pond Evap	Inch	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Greeley West	Avg. Temp ° F	30.78	24.87	39.41	46.83	56.82	72.84	75.98	73.27	65.78	51.15	42.76	34.23	51.23
Ref date as of 12/31/2021	Total Precip "	0.53	0.51	1.38	1.56	3.64	0.81	1.98	0.41	8.21	0.21	0.12	0.43	19.79
Site Type: Turf	Total Alfalfa ETr "	1.76	1.87	3.45	5.13	5.43	8.09	7.76	7.06	5.71	3.79	2.42	2.06	54.53
Total Growing Degee Days from March 1		0	0	102	203	316	593	721	659	501	270	155	71	3591
Gross Pond Evap	Inch	1.48	1.57	2.9	4.31	4.56	6.8	6.52	5.93	4.8	3.18	2.03	1.73	45.81
Net Pond Evap	Inch	1.11	1.21	1.93	3.22	2.01	6.23	5.13	5.64	0	3.04	1.95	1.43	32.9
Loveland	Avg. Temp ° F	29.89	24.18	38.39	45.73	55.5	70.65	74.49	72.09	65.63	51.19	44.4	36.23	50.7
Ref date as of 12/31/2021	Total Precip "	0.34	0.87	1.95	1.94	4.29	1.07	0.74	0.66	0.42	0.15	0.13	0.66	13.22
Site Type: Turf	Total Alfalfa ETr "	1.69	1.86	3.3	4.79	5.03	7.26	7.19	6.61	5.36	3.71	2.89	2.42	52.11
Total Growing Degee Days from March 1		0	0	104	207	313	575	698	640	516	307	197	93	3650
Gross Pond Evap	Inch	1.42	1.56	2.77	4.02	4.23	6.1	6.04	5.55	4.5	3.12	2.43	2.03	43.77
Net Pond Evap	Inch	1.18	0.95	1.41	2.67	1.22	5.35	5.52	5.09	4.21	3.01	2.34	1.57	34.52
Berthoud	Avg. Temp ° F	30.78	24.09	38.25	45.82	54.84	71	74.71	72.78	66.53	51.71	44.63	37.46	51.05
Ref date as of 12/31/2021	Total Precip "	0.39	0.51	1.82	1.59	4.07	0.53	1	0.58	0.15	0.06	0.05	0.45	11.2
Site Type: Turf	Total Alfalfa ETr "	1.86	2.08	3.43	5.03	5.06	8.1	8.13	7.76	6.17	3.95	2.7	2.52	56.79
Total Growing Degee Days from March 1		0	0	80	185	277	579	712	664	505	268	159	95	3524
Gross Pond Evap	Inch	1.56	1.75	2.88	4.23	4.25	6.8	6.83	6.52	5.18	3.32	2.27	2.12	47.71
Net Pond Evap	Inch	1.29	1.39	1.61	3.11	1.4	6.43	6.13	6.11	5.08	3.28	2.23	1.8	39.86
Longmont West	Avg. Temp ° F	30.83	24.56	38.39	45.56	54.95	70.77	74.37	72.14	65.19	50.85	45.6	37.63	50.9
Ref date as of 12/31/2021	Total Precip "	0.26	0.4	1.3	0.1	1.42	0.98	2.86	1.67	0.63	0.48	0.15	0	10.25
Site Type: Turf	Total Alfalfa ETr "	1.82	1.95	3.29	4.62	4.87	7.62	7.31	6.89	5.25	3.66	2.77	2.47	52.52
Total Growing Degee Days from March 1		0	0	0	0	239	555	693	631	484	287	184	96	3169
Gross Pond Evap	Inch	1.53	1.64	2.76	3.88	4.09	6.4	6.14	5.79	4.41	3.07	2.33	2.07	44.11
Net Pond Evap	Inch	1.35	1.36	1.85	3.81	3.1	5.71	4.14	4.62	3.97	2.74	2.22	2.07	36.94
Fort Lupton	Avg. Temp ° F	30.76	24.61	38.59	46.03	56.14	71.71	75.7	73.95	66.88	52.36	45.58	37.1	51.62
Ref date as of 12/31/2021	Total Precip "	0.33	0.67	1.49	1.48	3.21	0.43	0.37	1.26	0.32	0.32	0.19	0.37	10.44
Site Type: Turf	Total Alfalfa ETr "	1.99	2.23	3.77	5.32	5.03	9.03	9.2	8.53	7.06	4.88	3.45	2.9	63.39
Total Growing Degee Days from March 1		0	0	83	186	259	582	717	678	516	288	184	99	3592
Gross Pond Evap	Inch	1.67	1.87	3.17	4.47	4.23	7.59	7.73	7.17	5.93	4.1	2.9	2.44	53.27
Net Pond Evap	Inch	1.44	1.4	2.12	3.43	1.98	7.28	7.47	6.28	5.71	3.88	2.77	2.18	45.94
Boulder NW	Avg. Temp ° F	32.92	26.06	39.23	45.76	54.83	70.36	73.91	72.23	66.46	51.53	46.59	39.19	51.59
Ref date as of 12/31/2021	Total Precip "	0.28	0.69	1.83	2.77	4.93	2.59	1.78	1.77	0.34	0.32	0.18	0.15	17.63
Site Type: Turf	Total Alfalfa ETr "	1.61	1.86	1.56	2.51	4.51	7.2	6.94	7.02	5.75	3.83	3.34	2.92	49.05
Total Growing Degee Days from March 1		0	0	93	180	273	542	670	637	500	245	165	93	3398
Gross Pond Evap	Inch	1.35	1.56	1.31	2.11	3.79	6.05	5.83	5.9	4.83	3.22	2.81	2.45	41.21
Net Pond Evap	Inch	1.16	1.08	0.03	0.17	0.34	4.24	4.58	4.66	4.59	2.99	2.68	2.35	28.87
Boulder East	Avg. Temp ° F	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Ref date as of 5/2/2010	Total Precip "	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Site Type: Turf	Total Alfalfa ETr "	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Total Growing Degee Days from March 1		0	0	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Gross Pond Evap	Inch	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Net Pond Evap	Inch	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Boulder Flatiron	Avg. Temp ° F	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Ref date as of 5/2/2010	Total Precip "	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Site Type: Turf	Total Alfalfa ETr "	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Total Growing Degee Days from March 1		0	0	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Gross Pond Evap	Inch	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Net Pond Evap	Inch	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	0
Boulder SW	Avg. Temp ° F	34.28	26.65	39.75	45.94	54.66	70.05	73.31	72.4	66.63	53.29	49.04	41.75	52.31
Ref date as of 12/31/2021	Total Precip "	0.27	0.63	1.62	2.72	6.54	2.35	2.62	1.11	0.67	0.19	0.05	0.16	18.93
Site Type: Turf	Total Alfalfa ETr "	2.29	2.44	3.47	4.84	5.07	7.71	7.58	7.48	5.96	4.28	3.95	3.51	58.58
Total Growing Degee Days from March 1		0	0	74	163	247	523	653	621	469	252	175	96	3273
Gross Pond Evap	Inch	1.92	2.05	2.91	4.07	4.26	6.48	6.37	6.28	5.01	3.6	3.32	2.95	49.22
Net Pond Evap	Inch	1.73	1.61	1.78	2.16	0	4.83	4.53	5.51	4.54	3.46	3.28	2.84	36.27
Greeley04	Avg. Temp ° F	29.29	22.65	37.76	52.8	60.1	71.67	74.04	70.42	63.98	50.24	41.02	31.87	50.49
Ref date as of 12/31/2021	Total Precip "	0.09	0.12	0.68	0.96	2.34	0.23	3.15	0.31	0.54	0.15	0.12	0.02	8.71
Site Type: Fully irrigated	Total Alfalfa ETr "	2.27	2.48	3.9	1.31	2.33	10.64	8.58	7.9	6.74	5.28	3.28	3.28	57.99
Total Growing Degee Days from March 1		0	0	94	72	89	575	689	596	482	287	164	80	3128
Gross Pond Evap	Inch	1.91	2.08	3.28	1.1	1.96	8.94	7.21	6.64	5.66	4.44	2.76	2.76	48.74
Net Pond Evap	Inch	1.84	2	2.8	0.43	0.32	8.78	5	6.42	5.28	4.33	2.67	2.74	42.61