Pond Evaporation Calculation													1/31/24
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	2023	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	or Avg.
Ovid	Avg. Temp ° F	21.35	23.01	32.33	47.37	60.85	67.86	73.73	72.83	65.29	47.86	38.23	32.11	48.57
Ref date as of 12/31/2023	Total Precip "	1.46	0.04	0.96	0.45	3.8	1.97	1.48	2.94	1.68	0.79	0.32	0.37	16.26
Site Type: Fully irrigated	Total Alfalfa ETr "	0.81	1.48	3.22	7.5	7.1	7.74	9.16	9.23	7	4.96	4.01	2.78	64.99
Total Growing Degee Days from March 1		0	0	44	229	397	551	655	658	497	276	172	65	3544
Gross Pond Evap	Total "	0.68	1.24	2.7	6.3	5.96	6.5	7.69	7.75	5.88	4.17	3.37	2.34	54.58
Net Pond Evap	Total "	0	1.22	2.03	5.99	3.3	5.12	6.66	5.7	4.7	3.61	3.14	2.08	43.55
Crook	Avg. Temp ° F	21.14	23.57	32.41	46.85	60.13	66.77	72.51	71.38	64.28	47.52	37.53	32.11	48.02
Ref date as of 12/31/2023	Total Precip "	0.97	0.1	0.48	0.46	5.53	5.96	3.67	1.6	0.82	0.49	0.24	0.23	20.55
Site Type: Fully irrigated	Total Alfalfa ETr "	0.9	1.75	3.45	7.27	6.45	6.88	7.81	7.84	6.64	4.88	4.12	3.18	61.17
Total Growing Degee Days from March 1		0	0	43	222	384	519	638	620	485	279	171	61	3422
Gross Pond Evap	Inch	0.76	1.47	2.9	6.11	5.42	5.78	6.56	6.59	5.58	4.1	3.46	2.67	51.4
Net Pond Evap	Inch	0.08	1.4	2.56	5.78	1.55	1.61	3.99	5.47	5	3.76	3.29	2.51	37
Sterling	Avg. Temp ° F	20.95	22.63	33.06	46.83	59.87	66.12	72.56	71.79	64.93	48.29	37.49	32.6	48.09
Ref date as of 12/31/2023	Total Precip "	1.28	0.12	0.67	0.71	5.11	6	2.46	1.89	0.24	0.27	0.21	0.11	19.07
Site Type: Fully irrigated	Total Alfalfa ETr "	0.97	1.68	3.46	6.6	6.67	6.89	8.05	8.01	6.52	4.57	3.43	2.7	59.55
Total Growing Degee Days from March 1		0	0	45	220	371	493	642	629	494	281	172	69	3416
Gross Pond Evap	Inch	0.81	1.41	2.91	5.54	5.6	5.79	6.76	6.73	5.48	3.84	2.88	2.27	50.02
Net Pond Evap	Inch	0	1.33	2.44	5.05	2.03	1.59	5.04	5.41	5.31	3.65	2.73	2.19	36.77
Brush	Avg. Temp ° F	18.73	21.3	33.97	46.43	59.15	65.3	71.84	71.39	63.38	48.28	35.98	31.66	47.28
Ref date as of 12/31/2023	Total Precip "	1.4	0.18	0.82	0.41	7.36	6.83	2.59	1.11	0.39	0.48	0.28	0.26	22.11
Site Type: Fully irrigated	Total Alfalfa ETr "	0.98	1.76	3.93	6.8	6.72	6.72	7.41	8.22	5.67	4.85	3.06	2.75	58.87
Total Growing Degee Days from March 1		0	0	59	237	384	486	647	635	488	309	172	76	3493
Gross Pond Evap	Inch	0.82	1.48	3.3	5.71	5.64	5.64	6.22	6.9	4.76	4.07	2.57	2.31	49.42
Net Pond Evap	Inch	0	1.35	2.73	5.43	0.49	0.86	4.41	6.13	4.49	3.74	2.37	2.13	34.13
Fort Morgan	Avg. Temp ° F	20.83	23.53	34.55	47.2	59.96	65.78	72.28	71.62	64.91	49.31	37.45	32.78	48.35
Ref date as of 12/31/2023	Total Precip "	0.85	0.09	0.73	0.64	7.36	6.22	3.62	1.74	0.42	0.82	0.24	0.2	22.93
Site Type: Fully irrigated	Total Alfalfa ETr "	1	1.88	3.82	6.17	6.62	6.51	7.77	7.62	6.19	4.36	2.79	2.53	57.26
Total Growing Degee Days from March 1		0	0	59	224	383	492	649	637	490	299	165	69	3467
Gross Pond Evap	Inch	0.84	1.58	3.21	5.18	5.56	5.47	6.53	6.4	5.2	3.66	2.34	2.13	48.1
Net Pond Evap	Inch	0.25	1.52	2.7	4.73	0.41	1.11	3.99	5.18	4.91	3.09	2.18	1.99	32.06
Wiggins	Avg. Temp ° F	19.05	21.29	33.49	45.77	58.43	64.7	70.9	69.82	63.29	47.88	36.69	33	47.03
Ref date as of 12/31/2023	Total Precip "	0.58	0.14	0.5	0.81	5.69	6.18	3.05	3.08	0.13	0.28	0.11	0.22	20.77
Site Type: Fully irrigated	Total Alfalfa ETr "	0.99	1.78	4.12	6.6	6.83	7.17	8.29	7.88	6.57	4.98	3.2	2.91	61.32
Total Growing Degee Days from March 1		0	0	54	211	354	464	615	601	479	292	165	72	3307
Gross Pond Evap	Inch	0.83	1.5	3.46	5.54	5.74	6.02	6.96	6.62	5.52	4.18	2.69	2.44	51.5
Net Pond Evap	Inch	0.43	1.4	3.11	4.98	1.75	1.7	4.83	4.46	5.43	3.99	2.61	2.29	36.98
Fort Collins East	Avg. Temp ° F	24.12	28.37	33.59	45.8	58.58	63.88	69.28	67.55	61.97	46.52	37.06	33.62	47.53
Ref date as of 12/31/2023	Total Precip "	0.62	0.2	0.54	0.65	3.52	5.9	2.69	2.86	0.71	0.54	0.33	4.91	23.47
Site Type: Fully irrigated	Total Alfalfa ETr "	1.16	2.92	4.11	6.47	6.75	6.62	6.87	6.28	5.95	3.82	2.85	2.58	56.38
Total Growing Degee Days from March 1		0	0	44	203	357	437	564	560	461	259	140	62	3087
Gross Pond Evap	Inch	0.97	2.45	3.45	5.43	5.67	5.56	5.77	5.28	5	3.21	2.39	2.17	47.35
Net Pond Evap	Inch	0.54	2.31	3.07	4.98	3.21	1.43	3.89	3.27	4.5	2.83	2.16	0	32.19
Eaton	Avg. Temp ° F	22.86	26.01	32.79	44.87	57.68	63.54	69.61	68.27	62.53	48.99	36.78	33.42	47.28
Ref date as of 12/31/2023	Total Precip "	0.89	0.32	2.37	0.91	4.45	2.67	2.36	0	0	0	0.54	0.15	14.66
Site Type: Fully irrigated	Total Alfalfa ETr "	1.17	2.35	4.09	6.58	7.08	6.99	7.69	6.93	6.05	5.22	3.35	2.86	60.36
Total Growing Degee Days from March 1		0	0	39	192	343	441	583	568	475	288	145	57	3131
Gross Pond Evap	Inch	0.98	1.97	3.44	5.53	5.95	5.87	6.46	5.82	5.08	4.38	2.81	2.4	50.69
Net Pond Evap	Inch	0.36	1.75	1.78	4.89	2.83	4	4.81	5.82	5.08	4.38	2.44	2.3	40.44
Johnsons Corner	Avg. Temp ° F	24.67	28.96	34.92	47.25	58.36	63.95	72.27	71.09	65.31	51.05	41.1	36.48	49.62
Ref date as of 12/31/2023	Total Precip "	0.97	0.35	0.67	0.82	4.29	4.16	1.64	2.49	1.29	0.61	0.63	0.11	18.03
Site Type: Fully irrigated	Total Alfalfa ETr "	1.2	2.51	3.63	5.96	5.94	6.06	7.98	7.34	6.29	4.4	3.13	2.47	56.91
Total Growing Degee Days from March 1		0	0	43	195	329	437	638	624	485	277	146	61	3235
Gross Pond Evap	Inch	1.01	2.11	3.05	5.01	4.99	5.09	6.7	6.17	5.28	3.7	2.63	2.07	47.81
Net Pond Evap	Inch	0.33	1.86	2.58	4.43	1.99	2.18	5.56	4.42	4.38	3.27	2.19	2	35.19
Gilcrest	Avg. Temp ° F	20.4	24.61	34.83	47.06	58.95	64.69	71.95	70.19	63.66	49.38	37.73	34.16	48.13
Ref date as of 12/31/2023	Total Precip "	0.68	0.28	0.7	1.06	5.97	5.27	2.07	2.54	0.61	0.45	0.31	0.08	20.02
Site Type: Fully irrigated	Total Alfalfa ETr "	0.96	2.01	3.88	6.16	6.41	6.45	8.09	7.07	5.88	4.17	2.92	2.54	56.54
Total Growing Degee Days from March 1		0	0	53	215	359	454	630	602	484	284	156	70	3307
Gross Pond Evap	Inch	0.81	1.69	3.26	5.17	5.38	5.42	6.8	5.94	4.94	3.5	2.45	2.13	47.49
Net Pond Evap	Inch	0.33	1.49	2.77	4.43	1.21	1.73	5.35	4.16	4.51	3.19	2.24	2.08	33.49
Longmont South	Avg. Temp ° F	24.25	29.73	34.96	47.1	57.4	62.92	71.15	70.17	63.32	49.5	39.67	35.64	48.82
Ref date as of 12/31/2023	Total Precip "	0.68	0.48	0.49	1.19	5.09	4.58	2.55	0.92	1.3	0.47	0.42	0.29	18.46
Site Type: Fully irrigated	Total Alfalfa ETr "	1.29	2.72	4	6.07	5.69	5.83	7.83	6.89	5.67	4.22	2.94	2.25	55.4
Total Growing Degee Days from March 1		0	0	54	200	315	407	595	586	460	270	144	65	3096
Gross Pond Evap	Inch	1.08	2.28	3.36	5.1	4.78	4.9	6.58	5.79	4.76	3.54	2.47	1.89	46.53
Net Pond Evap	Inch	0.61	1.95	3.02	4.27	1.22	1.69	4.79	5.14	3.85	3.22	2.18	1.69	33.63
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 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
Fort Collins Central	Avg. Temp ° F	26.27	29.37	34.56	46.13	58.61	63.67	70.58	69.56	63.11	48.75	38.65	35.39	48.72
Ref date as of 122823/0/2023	Total Precip "	0	0	0.37	0.83	3.52	4.48	4.58	3.1	0.6	0.07	0	0	17.55
Site Type: Fully irrigated	Total Alfalfa ETr "	1.18	2.41	3.44	5.31	5.7	5.32	6.33	5.92	5.07	3.35	2.25	1.62	47.9
Total Growing Degee Days from March 1		0	0	40	188	345	381	584	582	467	282	149	64	3082
Gross Pond Evap	Inch	0.99	2.02	2.89	4.46	4.79	4.47	5.32	4.97	4.26	2.81	1.89	1.36	40.23
Net Pond Evap	Inch	0.99	2.02	2.63	3.88	2.32	1.33	2.11	2.8	3.84	2.77	1.89	1.36	27.94
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 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
Greeley West	Avg. Temp ° F	24.03	27.01	34.77	47.34	59.24	65.14	72.95	71.79	65.68	50.58	39.04	33.83	49.28
Ref date as of 12/31/2023	Total Precip "	1.05	0.47	0.76	1.11	5.54	3.12	3.31	1.03	0.29	0.47	0.47	0.16	17.78
Site Type: Fully irrigated	Total Alfalfa ETr "	0.83	1.78	3.49	5.29	5.73	5.4	6.42	6.31	4.76	3.6	1.84	1.88	47.33
Total Growing Degee Days from March 1		0	0	48	201	350	464	650	637	502	296	149	52	3349
Gross Pond Evap	Inch	0.7	1.5	2.93	4.44	4.81	4.54	5.39	5.3	4	3.02	1.55	1.58	39.76
Net Pond Evap	Inch	0	1.17	2.4	3.67	0.94	2.35	3.08	4.58	3.8	2.7	1.22	1.47	27.38
Loveland	Avg. Temp ° F	24.82	29.1	94.88	46.88	58.51	64.74	71.98	70.57	64.1	49.12	38.76	34.87	54.03
Ref date as of 122823/0/2023	Total Precip "	1.1	0.66	0.84	1.14	3.34	4.68	2.19	3.23	1.32	0.74	0.58	0.19	20.01
Site Type: Fully irrigated	Total Alfalfa ETr "	1.09	2.29	5.75	5.23	5.38	4.54	6.52	5.94	5.02	3.28	2.15	1.54	48.73
Total Growing Degee Days from March 1		0	0	880	237	360	356	635	622	496	299	162	63	4110
Gross Pond Evap	Inch	0.92	1.92	4.83	4.39	4.52	3.81	5.48	4.99	4.22	2.76	1.81	1.29	40.94
Net Pond Evap	Inch	0.15	1.46	4.24	3.6	2.18	0.54	3.94	2.73	3.29	2.24	1.4	1.16	26.93
Berthoud	Avg. Temp ° F	25.17	29.53	35.42	47.87	59.46	64.96	73.39	71.98	66.2	51.5	41.41	36.28	50.26
Ref date as of 12/31/2023	Total Precip "	0.9	0.42	0.48	3.09	3.81	4.23	4.56	0	0	0	0.57	0.17	18.23
Site Type: Fully irrigated	Total Alfalfa ETr "	0.97	2.13	4.41	5.42	5.91	6.3	7.67	6.72	5.42	3.39	2.14	1.89	52.37
Total Growing Degee Days from March 1		0	0	40	194	338	465	674	652	496	270	139	52	3320
Gross Pond Evap	Inch	0.81	1.79	3.7	4.55	4.96	5.29	6.44	5.64	4.55	2.85	1.8	1.59	43.97
Net Pond Evap	Inch	0.18	1.5	3.37	2.39	2.3	2.33	3.25	5.64	4.55	2.85	1.4	1.47	31.23
Longmont West	Avg. Temp ° F	25.6	31.18	35.83	48.1	59.45	64.91	73.31	71.61	65.18	50.19	40.14	35.52	50.09
Ref date as of 12/31/2023	Total Precip "	0	0	0	0	0	0	0	0	0	0	0	0	0
Site Type: Fully irrigated	Total Alfalfa ETr "	1.03	2.35	3.22	4.9	5.14	5.27	6.59	5.55	4.52	2.92	2.03	1.52	45.04
Total Growing Degee Days from March 1		0	0	51	199	334	450	650	626	489	282	149	67	3297
Gross Pond Evap	Inch	0.87	1.97	2.7	4.12	4.32	4.43	5.54	4.66	3.8	2.45	1.71	1.28	37.85
Net Pond Evap	Inch	0.87	1.97	2.7	4.12	4.32	4.43	5.54	4.66	3.8	2.45	1.71	1.28	37.85
Fort Lupton	Avg. Temp ° F	23.59	28.96	35.03	47.51	58.14	64.07	72.65	71.67	65.39	50.62	41.13	36.43	49.6
Ref date as of 12/31/2023	Total Precip "	0.89	0.33	0.61	1.44	8.6	3.77	1.43	1.82	0.94	0.51	0.33	0.18	20.85
Site Type: Fully irrigated	Total Alfalfa ETr "	1.28	2.74	4.09	6.54	6.45	6.88	8.89	8.32	6.87	4.77	3.55	2.88	63.26
Total Growing Degee Days from March 1		0	0	49	203	329	437	655	640	495	282	160	74	3324
Gross Pond Evap	Inch	1.08	2.3	3.44	5.49	5.42	5.78	7.47	6.99	5.77	4.01	2.98	2.42	53.15
Net Pond Evap	Inch	0.45	2.07	3.01	4.49	0	3.14	6.47	5.71	5.11	3.65	2.75	2.29	39.14
Boulder NW	Avg. Temp ° F	27.75	32.61	35.02	47.12	57.72	63.15	72.32	71.03	64.83	49.94	42.42	36.9	50.07
Ref date as of 12/31/2023	Total Precip "	0	0	0	0	0	0	0	0	0	0	0	0	0
Site Type: Fully irrigated	Total Alfalfa ETr "	1.47	2.84	3.47	5.52	5.64	5.68	7.42	6.47	5.43	3.31	2.82	1.81	51.88
Total Growing Degee Days from March 1		0	0	46	191	315	399	628	613	472	262	140	50	3116
Gross Pond Evap	Inch	1.23	2.39	2.91	4.64	4.74	4.77	6.23	5.43	4.56	2.78	2.37	1.52	43.57
Net Pond Evap	Inch	1.23	2.39	2.91	4.64	4.74	4.77	6.23	5.43	4.56	2.78	2.37	1.52	43.57
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	29.56	34.76	36.11	47.88	58.32	63.7	72.87	71.72	65.91	51.73	44.69	39.64	51.41
Ref date as of 12/31/2023	Total Precip "	0	0	0	0	0	0	0	0	0	0	0	0	0
Site Type: Fully irrigated	Total Alfalfa ETr "	1.92	3.5	3.88	5.63	5.38	5.78	7.58	6.63	5.64	3.58	3.1	2.62	55.24
Total Growing Degee Days from March 1		0	0	39	176	297	413	620	624	469	252	131	64	3085
Gross Pond Evap	Inch	1.61	2.94	3.26	4.73	4.52	4.86	6.37	5.57	4.74	3.01	2.6	2.2	46.41
Net Pond Evap	Inch	1.61	2.94	3.26	4.73	4.52	4.86	6.37	5.57	4.74	3.01	2.6	2.2	46.41
Greeley04	Avg. Temp ° F	20.98	24	34.41	46.73	58.68	64.51	71.01	69.85	63.76	49.31	36.46	32.67	47.7
Ref date as of 12/31/2023	Total Precip "	0.29	0.06	0.18	1.03	4.65	2.68	3.04	1.09	0.16	0.37	0.19	0.09	13.83
Site Type: Fully irrigated	Total Alfalfa ETr "	0.95	1.86	4.34	6.54	7.26	7.34	8.14	7.95	6.82	4.86	2.85	2.63	61.54
Total Growing Degee Days from March 1		0	0	56	215	353	461	611	603	490	291	155	62	3297
Gross Pond Evap	Inch	0.8	1.56	3.65	5.49	6.1	6.17	6.84	6.68	5.73	4.08	2.39	2.21	51.7
Net Pond Evap	Inch	0.6	1.52	3.52	4.77	2.84	4.29	4.71	5.92	5.62	3.82	2.26	2.15	42.02