Pond Evaporation Calculation													1/31/23
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	2022	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	or Avg.
Ovid	Avg. Temp ° F	25.22	25.51	36.55	47.06	57.95	72.71	77.72	76.53	66.9	49.23	31.34	22.28	49.08
Ref date as of 12/31/2022	Total Precip "	0.33	0.23	1.01	0.58	1.71	0.77	1.65	0.04	1.72	0.16	0.23	1	9.43
Site Type: Alfalfa	Total Alfalfa ETr "	1.98	2.76	4.4	7.74	8.15	11.11	10.41	9.76	7.44	5.13	2.63	1.15	72.66
Total Growing Degee Days from March 1		0	0	138	206	355	597	738	712	501	310	83	8	3648
Gross Pond Evap	Total "	1.66	2.32	3.7	6.5	6.85	9.33	8.74	8.2	6.25	4.31	2.21	0.97	61.04
Net Pond Evap	Total "	1.43	2.16	2.99	6.1	5.65	8.79	7.59	8.17	5.05	4.2	2.05	0.27	54.45
Crook	Avg. Temp ° F	24.59	25.21	37.09	46.88	56.98	71.66	76.79	75.07	65.68	48	31.11	22.55	48.47
Ref date as of 12/31/2022	Total Precip "	0.32	0.23	0.88	0.52	1.9	0.42	2.58	1.65	1.46	0.49	0.2	0.48	11.13
Site Type: Alfalfa	Total Alfalfa ETr "	1.76	2.52	4.39	7.67	7.58	10.32	9.33	8.38	6.52	4.68	2.5	1.18	66.83
Total Growing Degee Days from March 1		0	0	147	206	348	568	712	687	482	299	78	8	3535
Gross Pond Evap	Inch	1.48	2.12	3.69	6.44	6.37	8.67	7.84	7.04	5.48	3.93	2.1	0.99	56.15
Net Pond Evap	Inch	1.25	1.96	3.07	6.08	5.04	8.37	6.03	5.88	4.45	3.59	1.96	0.66	48.34
Sterling	Avg. Temp ° F	24.74	26.41	38.49	48.53	57.79	71.51	76.91	75.23	66.52	48.51	31.22	22.11	49
Ref date as of 12/31/2022	Total Precip "	0.36	0.31	1.05	0.23	2.37	0.73	0.99	1.56	1.22	0.46	0.24	0.71	10.23
Site Type: Alfalfa	Total Alfalfa ETr "	1.57	2.3	4.09	7.55	7.42	9.7	9.3	8.4	6.42	4.36	2.4	1.28	64.79
Total Growing Degee Days from March 1		0	0	155	214	350	571	733	700	500	283	71	18	3595
Gross Pond Evap	Inch	1.32	1.93	3.44	6.34	6.23	8.15	7.81	7.06	5.39	3.66	2.02	1.08	54.43
Net Pond Evap	Inch	1.07	1.72	2.7	6.18	4.57	7.64	7.12	5.96	4.54	3.34	1.85	0.58	47.27
Brush	Avg. Temp ° F	21.66	24.38	38.11	48.58	57.23	71.6	76.87	74.75	64.44	48.19	30.82	22.57	48.27
Ref date as of 12/31/2022	Total Precip "	0.62	0.42	1.2	0.12	1.88	0.94	4.11	0.3	0.75	0.34	0.29	1.01	11.98
Site Type: Alfalfa	Total Alfalfa ETr "	1.52	2.01	4.27	7.79	6.95	8.75	8.49	7.91	5.38	4.24	2.44	1.54	61.29
Total Growing Degee Days from March 1		0	0	181	249	374	567	723	682	477	307	82	35	3677
Gross Pond Evap	Inch	1.28	1.69	3.59	6.54	5.84	7.35	7.13	6.64	4.52	3.56	2.05	1.29	51.48
Net Pond Evap	Inch	0.84	1.39	2.75	6.46	4.52	6.69	4.25	6.43	3.99	3.32	1.85	0.59	43.08
Fort Morgan	Avg. Temp ° F	22.78	24.93	38.07	48.37	57.2	70.47	75.81	74.46	65.55	48.94	31.34	23.34	48.44
Ref date as of 12/31/2022	Total Precip "	0.43	0.4	1.37	0.13	2.27	1.7	4.02	0.35	1.16	0.02	0.15	0.5	12.5
Site Type: Turf	Total Alfalfa ETr "	1.43	2	3.96	7.24	7.44	8.58	8.75	8.12	5.64	3.87	2.22	1.49	60.74
Total Growing Degee Days from March 1		0	0	156	221	354	556	720	693	487	284	70	23	3564
Gross Pond Evap	Inch	1.2	1.68	3.33	6.08	6.25	7.21	7.35	6.82	4.74	3.25	1.86	1.25	51.02
Net Pond Evap	Inch	0.9	1.4	2.37	5.99	4.66	6.02	4.54	6.58	3.93	3.24	1.76	0.9	42.29
Wiggins	Avg. Temp ° F	20.66	23.66	36.74	47.1	56.08	69.84	74.85	73.22	64.58	47.5	29.84	21.7	47.15
Ref date as of 12/31/2022	Total Precip "	0.29	0.08	1	0.22	1.44	0.84	1.93	0.17	1.59	0.47	0.11	0.3	8.44
Site Type: Alfalfa	Total Alfalfa ETr "	1.27	1.95	4.13	7.91	7.62	9.64	9.26	8.49	6.05	4.07	2.23	1.47	64.09
Total Growing Degee Days from March 1		0	0	155	216	345	538	678	654	471	275	65	24	3421
Gross Pond Evap	Inch	1.07	1.64	3.47	6.64	6.4	8.1	7.78	7.13	5.08	3.42	1.87	1.23	53.83
Net Pond Evap	Inch	0.86	1.58	2.77	6.49	5.39	7.51	6.43	7.01	3.97	3.09	1.8	1.02	47.92
Fort Collins East	Avg. Temp ° F	24.32	25.19	38.19	47.53	55.97	68.4	73.24	71.16	62.93	49.37	30.62	26.47	47.78
Ref date as of 12/31/2022	Total Precip "	0.64	0.59	0.71	0.13	1.85	0.42	3.43	0.31	0.95	0.13	0.57	0.33	10.06
Site Type: Alfalfa	Total Alfalfa ETr "	1.53	2.14	4.41	7.74	7.54	9.3	8.39	7.57	5.52	4.59	2.31	1.94	62.98
Total Growing Degee Days from March 1		0	0	141	219	337	519	651	624	450	284	55	15	3295
Gross Pond Evap	Inch	1.29	1.8	3.7	6.5	6.33	7.81	7.05	6.36	4.64	3.86	1.94	1.63	52.91
Net Pond Evap	Inch	0.84	1.38	3.21	6.41	5.04	7.52	4.65	6.14	3.97	3.76	1.54	1.4	45.86
Eaton	Avg. Temp ° F	23.68	24.84	38.05	47.57	56.1	68.53	73.31	70.52	62.42	47.97	29.43	24.42	47.24
Ref date as of 12/31/2022	Total Precip "	0.67	0.58	0.8	0.07	1.99	0.26	1.76	0.85	0.99	0.17	0.67	0.44	9.25
Site Type: Alfalfa	Total Alfalfa ETr "	1.32	1.89	4.29	8.13	7.61	9.05	8.19	7.32	5.31	4.21	2.14	1.65	61.11
Total Growing Degee Days from March 1		0	0	138	221	340	525	665	620	443	267	50	4	3273
Gross Pond Evap	Inch	1.11	1.59	3.6	6.83	6.39	7.6	6.88	6.15	4.46	3.54	1.8	1.39	51.34
Net Pond Evap	Inch	0.64	1.18	3.04	6.78	5	7.42	5.65	5.55	3.77	3.42	1.33	1.08	44.86
Johnsons Corner	Avg. Temp ° F	26.45	25.88	39.39	48.85	56.38	69.31	75.01	73.39	66.13	52.37	33.15	27.5	49.48
Ref date as of 12/31/2022	Total Precip "	0.83	1.01	0.92	0.14	2.97	0.3	1.57	0.97	1.07	0.19	0.76	0.83	11.56
Site Type: Alfalfa	Total Alfalfa ETr "	1.35	1.86	3.91	7.21	6.83	8.57	8.48	7.87	5.81	4.37	2.18	1.71	60.15
Total Growing Degee Days from March 1		0	0	129	210	322	544	710	698	478	276	51	18	3436
Gross Pond Evap	Inch	1.13	1.56	3.28	6.06	5.74	7.2	7.12	6.61	4.88	3.67	1.83	1.44	50.52
Net Pond Evap	Inch	0.55	0.86	2.64	5.96	3.66	6.99	6.02	5.93	4.13	3.54	1.3	0.86	42.44
Gilcrest	Avg. Temp ° F	20.42	22.31	38.23	48.84	56.36	69.24	74.43	72.89	64.62	49.91	31.05	23.91	47.68
Ref date as of 12/31/2022	Total Precip "	0.79	0.67	1.06	0.24	3.2	1.07	2.02	0.84	0.95	0.52	0.49	0.54	12.39
Site Type: Alfalfa	Total Alfalfa ETr "	1.18	1.69	3.93	7.78	7.43	8.79	8.73	8.15	5.6	4.1	2.12	1.6	61.1
Total Growing Degee Days from March 1		0	0	141	230	344	538	690	668	469	286	57	12	3435
Gross Pond Evap	Inch	0.99	1.42	3.3	6.54	6.24	7.38	7.33	6.85	4.7	3.44	1.78	1.34	51.31
Net Pond Evap	Inch	0.44	0.95	2.56	6.37	4	6.63	5.92	6.26	4.04	3.08	1.44	0.97	42.66
Longmont South	Avg. Temp ° F	27.32	27.36	39.78	49.16	56.74	68.95	74.56	71.77	64.33	51	32	28.14	49.26
Ref date as of 12/31/2022	Total Precip "	0.59	0.85	0.76	0.16	2.79	0.39	1.42	1.48	0.89	0.54	0.77	1.2	11.84
Site Type: Alfalfa	Total Alfalfa ETr "	1.54	2.14	4.05	7.36	7.13	8.1	8.29	7.23	5.34	4.09	2.01	1.95	59.23
Total Growing Degee Days from March 1		0	0	148	222	326	525	682	648	449	263	50	29	3342
Gross Pond Evap	Inch	1.29	1.8	3.4	6.18	5.99	6.8	6.96	6.07	4.49	3.44	1.69	1.64	49.75
Net Pond Evap	Inch	0.88	1.2	2.87	6.07	4.04	6.53	5.97	5.04	3.86	3.06	1.15	0.8	41.47
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	26.07	25.89	38.4	47.57	55.44	67.51	72.98	71.29	62.75	48.52	31.4	27.41	47.94
Ref date as of 12/31/2022	Total Precip "	0.65	0.57	0.67	0.16	2.67	0.8	3.33	0.45	1.33	0.08	0	0	10.71
Site Type: Turf	Total Alfalfa ETr "	1.51	2.05	3.76	6.36	6.11	7.63	6.81	6.48	4.62	3.56	2	1.69	52.58
Total Growing Degee Days from March 1		0	0	130	200	319	496	641	621	437	267	58	20	3189
Gross Pond Evap	Inch	1.27	1.72	3.16	5.34	5.13	6.41	5.72	5.44	3.88	2.99	1.68	1.42	44.16
Net Pond Evap	Inch	0.81	1.32	2.69	5.23	3.26	5.85	3.39	5.13	2.95	2.93	1.68	1.42	36.66
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	24.39	25.32	38.95	49.01	56.95	69.97	75.81	74.01	65.86	50.83	31.97	25.55	49.05
Ref date as of 12/31/2022	Total Precip "	0.8	0.91	1.08	0.12	2.42	0.23	2.24	0.39	0.95	0.28	0.61	0.53	10.56
Site Type: Turf	Total Alfalfa ETr "	1.18	1.73	3.75	7.04	6.58	7.84	7.73	7.08	4.97	3.59	1.95	1.45	54.89
Total Growing Degee Days from March 1		0	0	135	221	342	556	718	696	480	272	50	15	3485
Gross Pond Evap	Inch	0.99	1.45	3.15	5.91	5.53	6.59	6.49	5.95	4.17	3.02	1.64	1.22	46.11
Net Pond Evap	Inch	0.43	0.82	2.39	5.83	3.83	6.42	4.93	5.67	3.51	2.82	1.21	0.85	38.71
Loveland	Avg. Temp ° F	26.37	25.56	39.26	48.98	56.75	69.23	75.17	72.49	64.44	50.39	31.66	27.13	48.95
Ref date as of 12/31/2022	Total Precip "	1	1.22	0.82	0.18	3.17	0.58	1.85	1.34	1.23	0.34	0.78	0.97	13.48
Site Type: Turf	Total Alfalfa ETr "	1.51	1.99	3.95	6.78	6.57	7.89	7.79	7.13	4.97	3.77	1.87	1.6	55.82
Total Growing Degee Days from March 1		0	0	154	228	352	556	713	682	487	309	67	21	3569
Gross Pond Evap	Inch	1.27	1.67	3.32	5.7	5.52	6.63	6.54	5.99	4.17	3.17	1.57	1.34	46.89
Net Pond Evap	Inch	0.57	0.82	2.74	5.57	3.3	6.22	5.25	5.05	3.31	2.93	1.02	0.67	37.45
Berthoud	Avg. Temp ° F	27.21	26.51	39.99	49.46	57.25	70.23	75.82	74.19	66.99	52.88	33.81	28.3	50.22
Ref date as of 12/31/2022	Total Precip "	0.7	0.83	0.91	0.08	2.78	0.24	2.24	1.52	0.87	0.31	0.65	1.05	12.18
Site Type: Turf	Total Alfalfa ETr "	1.28	1.85	3.89	6.91	6.87	8.23	8.2	7.4	5.33	3.91	2.03	1.64	57.54
Total Growing Degee Days from March 1		0	0	129	206	333	573	736	722	502	267	49	16	3533
Gross Pond Evap	Inch	1.08	1.55	3.27	5.8	5.77	6.91	6.89	6.22	4.48	3.28	1.71	1.38	48.34
Net Pond Evap	Inch	0.59	0.97	2.63	5.75	3.82	6.75	5.32	5.15	3.87	3.07	1.25	0.64	39.81
Longmont West	Avg. Temp ° F	27.58	27.11	40.01	49.84	57.23	69.88	75.76	73.87	66.07	51.29	33.11	29.22	50.08
Ref date as of 12/31/2022	Total Precip "	0.04	0.01	0.03	0.1	3.39	0.19	0.06	2.01	1.19	0.41	0	0	7.43
Site Type: Turf	Total Alfalfa ETr "	1.55	1.99	3.81	6.52	6.39	7.39	7.34	6.68	4.78	3.4	1.81	1.67	53.33
Total Growing Degee Days from March 1		0	0	133	215	331	564	722	697	478	259	57	39	3495
Gross Pond Evap	Inch	1.3	1.67	3.2	5.48	5.37	6.21	6.17	5.61	4.02	2.86	1.52	1.4	44.81
Net Pond Evap	Inch	1.27	1.66	3.18	5.41	2.99	6.07	6.12	4.2	3.18	2.57	1.52	1.4	39.57
Fort Lupton	Avg. Temp ° F	27.61	27.56	39.94	49.36	57.44	69.99	76.03	74.36	66.57	51.74	32.9	27.78	50.11
Ref date as of 12/31/2022	Total Precip "	1.03	1	1.09	0.17	2.69	2.55	0.71	0.92	0.9	0.61	0.47	0.91	13.05
Site Type: Turf	Total Alfalfa ETr "	1.61	2.15	4.34	7.41	8.01	9.01	9.25	8.35	6.38	4.38	2.23	2.02	65.14
Total Growing Degee Days from March 1		0	0	147	215	338	566	728	712	494	266	53	24	3543
Gross Pond Evap	Inch	1.35	1.81	3.65	6.22	6.73	7.57	7.77	7.01	5.36	3.68	1.87	1.7	54.72
Net Pond Evap	Inch	0.63	1.11	2.88	6.11	4.85	5.78	7.27	6.37	4.73	3.25	1.54	1.06	45.58
Boulder NW	Avg. Temp ° F	31.28	28.48	39.71	48.51	55.95	68.86	74.87	72.56	65.31	51.3	33.32	31.88	50.17
Ref date as of 12/31/2022	Total Precip "	1.04	1.17	1.01	0.14	3.97	0.15	1.29	2.19	1.49	0.27	0	0	12.72
Site Type: Turf	Total Alfalfa ETr "	2.12	3.14	5.13	8.55	7.11	6.98	7.28	7.01	4.89	3.82	1.97	2.16	60.16
Total Growing Degee Days from March 1		0	0	135	202	309	530	687	655	467	244	44	33	3306
Gross Pond Evap	Inch	1.78	2.64	4.31	7.18	5.97	5.86	6.12	5.89	4.11	3.21	1.65	1.81	50.53
Net Pond Evap	Inch	1.05	1.82	3.6	7.08	3.19	5.76	5.21	4.36	3.06	3.02	1.65	1.81	41.61
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	34.54	30.7	41.24	49.38	56.56	69.42	74.98	73.19	67.02	53.35	35.31	34.11	51.65
Ref date as of 12/31/2022	Total Precip "	0.01	0.01	0.04	0.12	3.3	0.27	2.82	2.87	1.23	0.22	0	0	10.89
Site Type: Turf	Total Alfalfa ETr "	2.4	2.66	4.16	6.62	6.65	7.8	7.9	7.04	5.3	4.28	2.21	2.7	59.72
Total Growing Degee Days from March 1		0	0	128	192	305	513	671	679	473	244	42	40	3287
Gross Pond Evap	Inch	2.02	2.23	3.49	5.56	5.59	6.55	6.64	5.91	4.45	3.6	1.86	2.27	50.17
Net Pond Evap	Inch	2.01	2.23	3.47	5.48	3.28	6.36	4.66	3.9	3.59	3.44	1.86	2.27	42.55
Greeley04	Avg. Temp ° F	20.74	23.7	38.1	48.17	56.46	68.9	73.83	71.64	63.93	49.23	30.86	23.6	47.43
Ref date as of 12/31/2022	Total Precip "	0.33	0.19	0.61	0.2	2.02	0.42	1.18	0.63	1.1	0.27	0.14	0.12	7.21
Site Type: Fully irrigated	Total Alfalfa ETr "	1.31	1.89	4.84	9.03	8.27	9.96	9.47	8.24	6.34	4.54	2.69	2.17	68.75
Total Growing Degee Days from March 1		0	0	142	228	346	541	680	654	465	286	56	15	3413
Gross Pond Evap	Inch	1.1	1.59	4.07	7.59	6.95	8.37	7.95	6.92	5.33	3.81	2.26	1.82	57.76
Net Pond Evap	Inch	0.87	1.45	3.64	7.45	5.53	8.07	7.13	6.48	4.56	3.62	2.16	1.74	52.7