Malheur Experiment Station

Information for Sustainable Agriculture

2003 WEATHER REPORT

Erik B. G. Feibert and Clinton C. Shock
Malheur Experiment Station
Oregon State University
Ontario, OR

Introduction

Air temperature and precipitation have been recorded daily at the Malheur Experiment Station since July 20, 1942. Installation of additional equipment in 1948 allowed for evaporation and wind measurements. A soil thermometer at 4-inch depth was added in 1967. A biophenometer, to monitor degree days, and pyranometers, to monitor total solar and photosynthetically active radiation, were added in 1985.

Since 1962, the Malheur Experiment Station has participated in the Cooperative Weather Station system of the National Weather Service. The daily readings from the station are reported to the National Weather Service forecast office in Boise, Idaho.

Starting in June 1997, the daily weather data and the monthly weather summaries have been posted on the Malheur Experiment Station web site on the internet at www.cropinfo.net. On June 1, 1992, in cooperation with the U.S. Department of the Interior, Bureau of Reclamation, a fully automated weather station, connected by satellite to the Northwest Cooperative Agricultural Weather Network (AgriMet) computer in Boise, Idaho, began transmitting data from Malheur Experiment Station. The automated station continually monitors air temperature, relative humidity, dew point temperature, precipitation, wind run, wind speed, wind direction, solar radiation, and soil temperature at 8-inch and 20-inch depths. Data are transmitted via satellite to the Boise computer every 4 hours and are used to calculate daily Malheur County crop water-use estimates. The AgriMet database can be accessed through the internet at http://www.usbr.gov/pn/agrimet/currentdata.html and is linked to the Malheur Experiment Station web page at www.cropinfo.net.

Methods

The ground under and around the weather stations was bare until October 17, 1997, when it was covered with turfgrass. The grass is irrigated with subsurface drip irrigation. The weather data are recorded each day at 8:00 a.m. Consequently, the data in the tables of daily observations refer to the previous 24 hours.

Evaporation is measured from April through October as inches of water evaporated from a standard 10-inch-deep by 4-ft-diameter pan over 24 hours. Evapotranspiration (Et) for each crop is calculated by the AgriMet computer using data from the AgriMet weather station and the Kimberly-Penman equation (Wright 1982). Reference Et is calculated for a theoretical 12- to 20-inch-tall crop of alfalfa assuming full cover for the whole season. Alfalfa mean Et is calculated for an alfalfa crop assuming a 15 percent reduction to account for cuttings. Evapotranspiration for all crops is calculated using the reference Et and factors for each crop that vary during the season depending on the degree of cover.

Wind run is measured as total wind movement in miles over 24 hours at 24 inches above the ground. Weather data averages in the tables refer to the years preceding and up to, but not including, the current year.

2003 Weather

The total precipitation for 2003 (8.78 inches) was lower than the 10-year and 59-year averages (Table 1).

The highest temperature for the year was 110° F on July 22, higher than the record of 108° F on August 4, 1961 (Table 2). The lowest temperature for the year was 15° F occurring on various dates in February, November, and December. Average monthly maximum and minimum air temperatures for all months except April, May, and November were higher than the 10-year and 60-year averages (Table 2). July had 13 days with maximum air temperatures equal to or above 100°F.

The months of June, July, August, and October had 17, 18, 11, and 69 percent more growing degree days (50° to 86°F), respectively, than the 17-year average (Table 3). The total number of growing degree days in 2003 (3,443) was the second highest since measurements started being taken in 1986 (3,446 in 1988). Compared to 1994 (the second highest for growing degree days in the last 13 years) the growing degree days in 2003 accumulated more rapidly in July and then again in October (Fig. 1). In 1994 the growing degree days accumulated more evenly during the season. July had the highest number of degree days in the above-optimal range (86° to 104°F) since 1991 (Table 4). The total number of degree days in the above-optimal range in 2003 (130) was second to 1994 with 147.

The months of January, and April through October had total wind runs lower than the 10-year and 55-year averages (Table 5). Total pan-evaporation for June and July were 20 and 11 percent higher than the 10-year and 54-year averages (Table 6). Total Et for all crops in 2003 was higher than the 10-year average (Table 7).

From March through November the average monthly maximum and minimum 4-inch soil temperatures were lower than the 10-year and 35-year averages (Table 8). In January, February, and December the average monthly maximum and minimum 4-inch soil temperatures were higher than the 10-year and 35-year averages. The difference in soil temperature between 2003 and the averages is probably influenced by the installation of turf around the weather station in October of 1997.

The last spring frost ([32°F) occurred on May 19, 21 days later than the 27-year average date of April 28; the first fall frost occurred on October 11, 7 days later than the 27-year average date of October 4 (Table 9).

The maximum air temperature in 2003 was 110° F on July 22, surpassing the previous record of 108° F on August 4, 1961 (Table 10).

Total snowfall for 2003 (4.5 inches) was the lowest in the last 10 years and the lowest since 1943 (Table 11).

References

Wright, J.L. 1982. New evapotranspiration crop coefficients. J. Irrig. Drain. Div., ASCE 108:57-74.

Table 1. Monthly precipitation at the Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2003.

Year	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Total
	----------------------------------------------------- inches -----------------------------------------------------
1991	0.59	0.44	0.88	0.81	1.89	1.09	0.01	0.04	0.35	1.01	1.71	0.43	9.25
1992	0.58	1.36	0.25	0.74	0.21	1.43	0.36	0.01	0.09	0.95	1.15	1.51	8.64
1993	2.35	1.02	2.41	2.55	0.70	1.55	0.18	0.50	0.00	0.80	0.64	0.60	13.30
1994	1.20	0.57	0.05	1.02	1.62	0.07	0.19	0.00	0.15	1.23	2.46	1.49	10.05
1995	2.67	0.28	1.58	1.16	1.41	1.60	1.10	0.13	0.07	0.57	0.88	2.56	14.01
1996	0.97	0.86	1.03	1.19	2.39	0.12	0.32	0.31	0.59	0.97	1.18	2.76	12.69
1997	2.13	0.17	0.25	0.66	0.67	0.86	1.40	0.28	0.40	0.43	1.02	0.94	9.21
1998	2.26	1.45	0.95	1.43	4.55	0.36	1.06	0.00	1.00	0.04	1.07	1.11	15.28
1999	1.64	2.50	0.59	0.23	0.28	1.02	0.00	0.09	0.00	0.40	0.49	0.73	7.97
2000	2.01	2.14	0.97	0.72	0.28	0.26	0.03	0.06	0.39	1.74	0.38	0.66	9.64
2001	1.15	0.41	1.11	0.70	0.37	0.64	0.32	0.00	0.10	0.68	1.33	1.00	7.78
2002	0.77	0.27	0.49	0.77	0.09	0.60	0.14	0.10	0.36	0.29	0.44	1.86	6.18
2003	1.46	0.48	0.99	1.12	1.52	0.24	0.36	0.11	0.15	0.02	0.86	1.47	8.78
10-yr avg	1.72	0.97	0.94	1.04	1.24	0.71	0.47	0.15	0.31	0.71	1.01	1.37	10.64
60-yr avg	1.35	0.96	0.95	0.80	1.03	0.78	0.26	0.38	0.49	0.70	1.16	1.32	10.19

Table 2. Monthly air temperature, Malheur Experiment Station, Oregon State University, Ontario, OR, 2003.

	Jan		Feb		Mar		Apr		May		Jun		Jul		Aug		Sep		Oct		Nov		Dec
	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min
	--------------------------------------------------------------------- ^oF ----------------------------------------------------------------
Highest	49	40	58	40	74	50	75	50	98	64	98	64	110	73	101	74	94	59	87	65	73	45	57	40
Lowest	28	21	39	15	44	20	47	28	59	32	69	45	86	55	84	51	58	35	47	23	37	15	27	15
2003 avg	41	31	48	28	58	35	62	39	73	46	85	55	97	62	92	59	82	48	72	42	47	27	43	30
10-yr avg	37	24	44	26	55	31	64	37	73	46	80	51	91	58	90	54	81	47	66	36	48	28	38	24
59-yr avg	35	20	43	25	55	31	64	37	74	45	82	52	91	58	90	55	80	46	65	36	48	28	37	22

Figure 1. Cumulative growing degree days (50-86°F) over time for selected years compared to 13-year average, Malheur Experiment Station, Oregon State University, Ontario, OR.

Table 3. Monthly total growing degree days (50-86°F), Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2003.

Year	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Total
1991	0	13	16	124	212	389	776	718	436	194	1	0	2,879
1992	0	13	106	202	482	574	639	704	385	174	4	0	3,283
1993	0	0	23	81	423	358	464	524	408	252	6	0	2,539
1994	0	2	92	189	369	523	794	774	509	144	2	0	3,398
1995	0	29	32	106	293	433	680	588	472	101	3	10	2,747
1996	0	5	53	135	243	446	805	658	364	194	18	2	2,923
1997	4	0	81	117	419	509	661	706	481	157	20	0	3,154
1998	0	2	52	112	68	571	802	749	515	151	16	4	3,042
1999	0	2	43	72	329	459	683	703	416	184	30	0	2,921
2000	0	4	36	194	342	536	751	743	368	133	2	0	3,109
2001	0	0	63	126	401	488	715	761	472	155	27	0	3,208
2002	0	2	32	137	319	562	805	621	437	142	14	2	3,073
2003	0	4	72	112	319	594	846	754	448	281	11	2	3,443
17-year avg	0	6	53	152	324	510	720	682	435	166	13	1	3,064

Table 4. Monthly total degree days in the above ideal 86 -104°F range, Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2003.

Year	Apr	May	Jun	Jul	Aug	Sep	Oct	Total
1991	0	0	2	41	36	4	0	83
1992	0	5	20	23	54	2	0	104
1993	0	4	4	2	11	5	0	26
1994	0	2	16	68	54	7	0	147
1995	0	0	4	23	22	7	0	56
1996	0	0	5	54	32	4	0	95
1997	0	4	0	27	31	5	0	67
1998	0	0	0	63	45	14	0	122
1999	0	1	2	21	16	1	0	41
2000	0	0	7	41	43	4	0	95
2001	0	5	7	25	45	4	0	86
2002	0	0	14	54	11	5	0	85
2003	0	5	9	74	36	5	0	130
13-yr avg	0	2	7	38	34	6	0	87

Table 5. Wind-run daily totals and monthly totals, Malheur Experiment Station, Oregon State University, Ontario, OR, 2003.

Daily	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
	------------------------------------------- miles -----------------------------------------------
Mean	33	71	87	69	56	49	44	35	30	36	60	79
Max.	106	196	250	131	126	100	110	82	135	133	158	204
Min.	5	17	20	29	21	13	10	10	6	6	18	23
Annual total	-------------------------------------------- miles ------------------------------------------------
2003	1,029	1,995	2,684	2,066	1,730	1,457	1,365	1,078	886	1,108	1,794	2,450
10-yr average	1,634	1,897	2,393	2,500	2,326	1,987	1,800	1,737	1,616	1,815	1,596	1,842
55-yr average				2,151	1,941	1,574	1,479	1,336	1,259	1,293

Table 6. Pan-evaporation totals, Malheur Experiment Station, Oregon State University, Ontario, OR, 2003.

Totals	April	May	Jun	Jul	Aug	Sep	Oct	Total
Daily	-------------------------------------- inches ---------------------------------------
Mean	0.18	0.27	0.38	0.40	0.33	0.24	0.17
Max.	0.33	0.47	0.48	0.64	0.49	0.41	0.31
Min.	0.08	0.09	0.26	0.08	0.14	0.03	0.03
Annual	---------------------------------------- inches ------------------------------------
2003	5.51	8.22	11.30	12.48	10.09	7.21	5.30	60.11
10-yr avg	6.03	8.82	9.42	11.29	10.72	7.38	4.32	57.98
55-yr avg	5.61	7.71	8.90	11.13	9.64	6.30	3.24	52.53

Table 7. Total Et (acre-inches/acre), Malheur Experiment Station, Oregon State University, Ontario, OR, 1992-2003.

Year	Reference Et	Alfalfa (mean)	Winter grain	Spring grain	Sugar beet	Onion	Potato	Dry bean	Field corn	1st year poplar	2nd year poplar	3rd year + poplar
1992	53.7	44.4	26.9	27.9	36.1	30.3	28.8	21.3	29.8	--	--	--
1993	51.9	36.4	21.3	22.7	29.3	24.1	22.8	17.9	23.7	--	--	--
1994	57.6	40.6	21.3	22.6	34.5	29.5	28.2	21.1	27.7	--	--	--
1995	49.6	37.1	18.9	22.2	29.0	26.7	23.6	16.7	23.7	--	--	--
1996	52.8	39.8	22.3	24.1	32.9	27.2	26.3	19.5	25.7	--	--	--
1997	55.2	41.5	23.8	25.3	33.4	28.0	26.6	19.7	25.1	--	--	--
1998	55.0	40.7	21.3	23.9	32.4	28.2	26.2	21.0	27.9	23.9	37.1	44.0
1999	58.6	43.9	25.0	26.4	33.7	28.9	26.5	21.7	28.5	24.3	37.8	45.5
2000	58.7	45.5	26.0	25.7	38.3	32.0	29.5	24.1	30.6	24.9	38.9	47.1
2001	57.9	43.8	25.5	27.2	34.8	30.3	27.4	21.4	29.1	23.7	37.0	44.7
2002	58.8	41.7	25.9	28.7	35.2	30.4	27.7	21.9	27.8	23.6	36.7	44.4
2003	54.2	44.1	27.5	31.7	39.1	32.0	32.4	22.5	29.6	24.3	37.9	45.9
10-year average	55.1	41.4	23.2	24.8	33.4	28.5	26.6	20.4	27.2	24.2	37.7	45.3

Table 8. Monthly soil temperature at 4-inch depth, Malheur Experiment Station, Oregon State University, Ontario, OR, 2003.

	Jan		Feb		Mar		Apr		May		Jun		Jul		Aug		Sep		Oct		Nov		Dec
	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min
	----------------------------------------------------------------- ^oF ------------------------------------------------------------
Highest	40	39	43	42	49	46	57	51	85	65	75	67	79	73	76	71	72	68	65	62	46	43	44	43
Lowest	34	32	35	33	37	34	45	37	53	49	67	61	70	62	70	64	60	56	48	44	36	34	34	33
2002 avg	37	36	39	37	44	41	51	46	61	55	71	64	74	68	73	68	65	61	57	53	42	38	39	37
10-yr avg	33	32	38	35	49	41	59	49	69	58	77	65	84	72	82	72	74	65	60	52	44	41	35	34
35-yr avg	33	32	38	34	50	41	61	48	72	58	81	66	89	74	87	73	76	63	60	51	44	39	34	33

Table 9. Last and first frost ([32°F) dates and number of frost-free days, Malheur Experiment Station, Oregon State University, Ontario, OR, 1990-2003.

Year	Date of last frost	Date of first frost	Total frost-free days
Year	Spring	Fall	Total frost-free days
1990	May 8	Oct 7	152
1991	Apr 30	Oct 4	157
1992	Apr 24	Sep 14	143
1993	Apr 20	Oct 11	174
1994	Apr 15	Oct 6	174
1995	Apr 16	Sep 22	159
1996	May 6	Sep 23	140
1997	May 3	Oct 8	158
1998	Apr 18	Oct 17	182
1999	May 11	Sep 28	140
2000	May 12	Sep 24	135
2001	Apr 29	Oct 10	164
2002	May 8	Oct 12	157
2003	May 19	Oct 11	145
1976-2002 Avg	April 28	October 4	159

Table 10. Record weather events at the Malheur Experiment Station, Oregon State University, Ontario, OR, 1943-2003.

Record event	Measurement	Date
Greatest annual precipitation	16.87 inches	1983
Greatest monthly precipitation	4.55 inches	May 1998
Greatest 24-hour precipitation	1.52 inches	Sep 14, 1959
Greatest annual snowfall	40 inches	1955
Greatest 24-hour snowfall	10 inches	Nov 30, 1975
Earliest snowfall	1 inch	Oct 25, 1970
Highest air temperature	110°F	July 22, 2003
Total days with maximum air temp. m100°F	17 days	1971
Lowest air temperature	-26°F	Jan 21 and 22, 1962
Total days with minimum air temp. [0°F	35 days	1985
Lowest soil temperature at 4-inch depth	12°F	Dec 24, 25, and 26, 1990

Table 11. Annual snowfall totals at the Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2003.

1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	10-yr avg	60-yr avg
-------------------------------------------------------- inches --------------------------------------------------------
7.5	15.5	36.0	32.0	15.0	14.5	5.8	14.6	13.2	13.8	15.5	11.5	4.5	17.2	18.5

MES Publications, MES Notice of events, Vegetation,Malheur County, Leslie Gulch,Succor Creek,Owyhee River,Local wildlife,Strawberry Mountain, Eagle Caps

For additional information about the Malheur Agricultural Experiment Station, please send an e-mail request to:

Dr. Clinton C. Shock

Clinton.Shock@oregonstate.edu

Malheur Agricultural Experiment Station

595 Onion Avenue

Ontario, OR 97914

(541) 889-2174

FAX (541) 889-7831

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Last updated Friday July 30, 2004 .