Malheur Experiment Station Information for Sustainable Agriculture

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-in depth was added in 1967. A biophenometer to monitor degree-days, and pyranometers to monitor 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.

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-in and 20-in depths. Data is transmitted via satellite to the Boise computer every 4 hours and is used to calculate daily Malheur County crop water-use estimates. The Agrimet database can be accessed via computer modem or through the Internet at: www.pn.usbr.gov/agrimet and is linked to the Malheur Experiment Station web page at www.cropinfo.net.

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.

The ground under and around the weather stations was bare, but it was covered with turf grass on October 17, 1997. The grass is irrigated with subsurface drip irrigation. The weather data is recorded each day at 8:00 a.m. All data pertains to the preceding 24-hour period except the 8:00 a.m. air temperature.

Evaporation is measured from April through October as inches of water evaporated from a standard 10-in deep by 4-ft diameter pan over 24 hours. Wind run is measured as total wind movement in miles over a 24 hour period measured at 24 inches above ground level. Weather data averages in the tables refer to the years preceding and up to, but not including, the current year.

The spring was drier, cooler, and windier than normal. The months of March through May had total precipitation lower than the 10 year and 55 year averages (Table 1). The month of April was substantially cooler, with 52 percent fewer growing degree-days (50 to 86°F) than the 10-year average (Table 2 and Figure 1). The months of February through May had total wind runs higher than the 8-year average (Table 3). April had a 41 percent higher wind run than the 8-year average. Pan evaporation for April was 15 percent higher than the 10-year average (Table 4).

The summer was drier than normal. Only 0.09 inches of precipitation was recorded from July through September (Table 1). Although the spring was cooler than normal, the months of June through August had a total number of growing degree-days close to the normal. 1999 was similar to 1996 in the pattern of growing degree-day accumulation (Figure 1). Compared to 1996 and 1999, 1997 accumulated more growing degree-days in the spring and summer, and 1998 accumulated more growing degree-days in August and September. There were 55 percent fewer degree-days in the above optimal range (86 to 104°F) compared to the previous 9-year mean (Table 5).

Mean monthly maximum air temperatures were close to the 10-year and 53-year means (Table 6).

From March through October, the mean monthly maximum and minimum 4-in soil temperatures were lower than the 10-year and 31-year means (Table 7). The difference in soil temperature between 1999 and the mean probably is influenced by the installation of turf around the weather station in October of 1997. The soil remained warmer in winter and cooler in spring and summer. The last spring frost ([32°F) occurred on May 11, 14 days later than the 22-year mean date of April 27; the first fall frost occurred on September 28, 7 days earlier than normal (Table 8).

The weather in 1999 did not exceed any record weather events recorded over the 54-year history for the Malheur Experiment Station (Table 9). The highest temperature for the year was 104°F on July 29 (Table 5). The lowest temperature for the year was 14°F on February 5 and 11. Total precipitation was 7.97 inches for the year, 27 percent lower than the 10-year station average and 23 percent lower than the 55-year station average (Table 1). Total pan-evaporation for April through October was 59.6 inches, close to the 10-year mean and higher than the 50-year mean (Table 4). Total snowfall for 1999 was 13.2 in, lower than the 10-year and 55-year means, respectively (Table 10).

Table 1. Monthly precipitation at the Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1989-1999.

Year	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Total
	----------------------------------------------------- inches -----------------------------------------------------
1989	0.88	1.27	2.17	0.50	0.60	0.77	0.08	0.94	0.83	0.86	0.24	0.01	9.15
1990	0.44	0.35	0.72	1.52	1.70	0.36	0.04	0.61	0.00	0.49	0.69	0.29	7.21
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
10-yr avg	1.41	0.78	1.03	1.16	1.57	0.82	0.47	0.28	0.35	0.74	1.13	1.17	10.91
55-yr avg	1.35	0.93	0.96	0.82	1.10	0.79	0.27	0.41	0.51	0.70	1.20	1.35	10.39

Table 2. Cumulative monthly growing degree-days (50 to 86°F), Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1989-1999.

Year	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
1989	0	0	13	197	469	1,018	1,751	2,332	2,721	2,838	2,852	2,852
1990	2	9	88	327	588	1,085	1,819	2,454	3,039	3,077	3,077	3,077
1991	0	13	29	153	365	754	1,530	2,248	2,684	2,878	2,879	2,879
1992	0	13	119	321	803	1,377	2,016	2,720	3,105	3,279	3,283	3,283
1993	0	0	23	104	527	885	1,349	1,873	2,281	2,533	2,539	2,539
1994	0	2	94	283	652	1,175	1,969	2,743	3,252	3,396	3,398	3,398
1995	0	29	61	167	460	893	1,573	2,161	2,633	2,734	2,737	2,747
1996	0	5	58	193	436	929	1,687	2,345	2,709	2,903	2,921	2,923
1997	4	4	85	202	621	1,130	1,791	2,497	2,977	3,134	3,154	3,154
1998	0	2	54	166	400	805	1,607	2,356	2,871	3,022	3,038	3,042
1999	0	2	45	117	446	905	1,588	2,291	2,707	2,891	2,921	2,921
10-yr avg	1	8	62	211	516	1,000	1,709	2,373	2,827	2,979	2,988	2,989

Figure 1. Cumulative degree-days (50 to 86°F) over time for years 1996 to 1999, Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1999.

Table 3. Daily wind-run totals and monthly totals, Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1999.

Daily	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
	-------------------------------------------- miles ------------------------------------------------
Max.	183	200	260	246	159	141	104	133	158	173	117	156
Min.	27	21	29	41	36	28	23	27	22	20	20	13
Average	64	90	84	111	96	65	61	64	62	57	47	57
Annual total	-------------------------------------------- miles ------------------------------------------------
1998	1,916	2,426	2,602	3,343	2,976	1,951	1,889	1,927	1,874	1,771	1,410	1,754
8-yr average	1,564	1,668	2,356	2,380	2,232	1,960	1,760	1,632	1,568	1,838	1,673	1,738
50-yr average				2,113	1,891	1,539	1,452	1,299	1,230	1,269

Table 4. Pan-evaporation totals. Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1999.

Totals	April	May	Jun	Jul	Aug	Sep	Oct	Total
Daily	-------------------------------------- inches ---------------------------------------
Mean	0.23	0.3	0.29	0.39	0.31	0.28	0.15
Max.	0.45	0.57	0.46	0.61	0.54	0.43	0.35
Min.	0.05	0.16	0.07	0.27	0.15	0.16	0.06
Annual	---------------------------------------- inches ------------------------------------
1999	6.87	9.34	8.73	12.08	9.56	8.31	4.73	59.62
10-yr avg	6.00	8.72	9.52	11.48	10.41	7.54	4.33	59.12
50-yr avg	5.54	7.59	8.82	11.07	9.56	6.22	3.16	51.32

Table 5. Monthly degree-days (86 to 104°F), Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1990-1999.

Year	Apr	May	Jun	Jul	Aug	Sep	Oct	Total
1990	0	0	13	56	41	14	0	124
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
9-yr avg	0	2	7	40	36	7	0	92

Table 6. Monthly air temperature, Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1999.

	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
	---------------------------------------------------------------------- ° F ----------------------------------------------------------------
Max.	50	35	61	41	70	40	80	44	92	57	97	63	104	68	97	67	90	61	81	54	68	42	56	35
Min.	31	17	32	14	44	24	41	19	54	29	58	39	73	42	74	40	63	31	50	25	41	20	22	15
1999 avg	41	28	42	28	56	32	62	35	71	43	80	51	90	55	91	56	80	45	69	37	55	33	37	25
10-yr avg	36	21	43	23	56	32	65	38	74	46	81	52	90	57	90	54	82	47	66	35	48	27	38	20
53-yr avg	35	20	43	25	55	31	64	37	74	45	82	52	91	57	90	55	80	46	65	36	48	28	37	22

Table 7. Monthly 4 inches soil temperature, Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1999.

	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
	----------------------------------------------------------------- °F ------------------------------------------------------------
Max.	37	37	42	38	48	43	55	51	66	61	74	66	76	70	78	69	68	63	58	55	49	47	44	42
Min.	29	29	32	30	37	35	41	37	49	47	56	55	67	62	67	59	57	52	48	45	39	38	31	26
1999 mean	33	33	35	33	42	39	49	44	56	52	67	62	72	66	72	66	65	60	54	50	45	43	36	34
10-yr mean	34	33	39	35	50	42	61	49	72	58	79	66	87	73	85	73	77	66	61	52	45	40	35	33
31-yr mean	33	32	38	34	50	41	62	48	74	58	82	67	90	74	88	74	77	64	61	51	44	39	34	33

Table 8. Last and first frost ([32°F) dates and number of frost-free days, Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1990-1999.

Table 9. Record weather events through 1999 at the Malheur Experiment Station, Oregon State University, Ontario, Oregon.

Record event	Measurement	Date
Greatest annual precipitation	16.87 in	1983
Greatest monthly precipitation	4.55 in	May 1998
Greatest 24-hour precipitation	1.52 in	Sep 14, 1959
Greatest annual snowfall	40 in	1955
Greatest 24-hour snowfall	10 in	Nov 30, 1975
Earliest snowfall	1 in	Oct 25, 1970
Highest air temperature	108°F	Aug 4, 1961
Total days with max. air temp. m 100°F	17 days	1971
Lowest air temperature	-26°F	Jan 21 and 22, 1962
Total days with min. air temp. [ 0°F	35 days	1985
Lowest 4-in soil temperature	12°F	Dec 24, 25, and 26, 1990

Table 10. Annual snowfall totals at the Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1988-1999.

1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	10-yr avg	55-yr avg
inches
34.8	25.1	5.7	7.5	15.5	36.0	32.0	15.0	14.5	5.8	14.6	13.2	17.2	18.8

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Malheur Agricultural Experiment Station

Last updated  Tuesday July 30, 2002 .