2010 WEATHER REPORT

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

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. 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.

A biophenometer, to monitor degree days, and pyranometers, to monitor total solar and photosynthetically active radiation were added in 1985. 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, linked by satellite to the Northwest Cooperative Agricultural Weather Network (AgriMet) computer in Boise, Idaho, began transmitting data from Malheur Experiment Station. The automated Agrimet 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 a computer in Boise 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 www.usbr.gov/pn/agrimet and from links on the Malheur Experiment Station web page at www.cropinfo.net.

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 manually observed 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 class A pan (10 inches deep by 4-ft diameter) over 24 hours. Evapotranspiration (ET_c) for each crop is calculated by the AgriMet computer using data from the AgriMet weather station and the Kimberly-Penman equation (Wright 1982). Agrimet calculates reference evapotranspiration (ET₀) for a theoretical 12- to 20-inch-tall crop of alfalfa assuming full cover for the whole season. Evapotranspiration for all crops is calculated using ET₀ and crop coefficients for each crop. These crop coefficients vary throughout the growing season based on the plant growth stage (crop cover). The crop coefficients are tied to the plant growth stage by three dates: start, full cover, and termination dates. Start dates are the beginning of vegetative growth in the spring for perennial crops or the emergence date for row crops. Full cover dates are typically when plants reach full foliage. Termination dates are defined by harvest, frost, or dormancy. Alfalfa mean ET_c is calculated for an alfalfa crop using ET₀ and assuming a 15 percent reduction to account for cuttings.

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, except evapotranspiration, refer to the years preceding and up to, but not including, the current year.

The total precipitation for 2010 (15.8 inches) was higher than the 10-year (9.75 inches) and 67-year (10.05 inches) averages (Table 1). Precipitation for December (4.19 inches) was three times normal and was the highest recorded. Total snowfall for 2010 (28.0 inches) was higher than the 10-year average (13.9 inches) and the 66-year average (18.0 inches) (Table 2).

The highest air temperature for 2010 was 100°F on July 17 and July 26 (Table 3). The lowest temperature for the year was 7°F on November 25.

April, May, and June had fewer accumulated growing degree-days (50 to 86°F) than the 23-year average (Table 4, Fig. 1). The total accumulated growing degree-days for 2010 (2,780 degree-days) was the third lowest since 1986. In 1993 there were 2,539 degree-days and in 1995 there were 2,747 degree-days. The total number of degree-days in the above-optimal range (86to 104°F) in 2010 was below the average (Table 5).

Total wind runs for all months, except February and December, were higher than the 10-year and 62-year averages (Table 6). Total pan-evaporation for April through October was close to the 10-year and 62-year averages (Table 7). In 2010, total accumulated reference evapotranspiration and ET_c estimated values for all crops were close to the 18-year averages (Table 8).

The average monthly maximum and minimum 4-inch soil temperatures for all months were close to the 10-year average (Table 9).

The last spring frost (≤32°F) occurred on May 7, 9 days later than the 33-year-average date of April 28; the first fall frost occurred on October 12, 6 days later than the 33-year-average date of October 6 (Table 10).

December had the highest precipitation since observations were begun (Table 11).

Wright, J.L. 1982. New evapotranspiration crop coefficients. Journal of Irrigation and Drainage Division, American Society of Civil Engineers 108:57-74.

Table 1. Monthly precipitation at the Malheur Experiment Station, Oregon State University, Ontario, OR, 1991-2010.

Table 2. Annual snowfall totals at the Malheur Experiment Station, Oregon State University, Ontario, OR, 1993-2010.

1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007	2008	2009	2010	10-yr avg	66-yr avg
36.0	32.0	15.0	14.5	5.8	14.6	13.2	13.8	15.5	11.5	4.5	24.0	13.5	12.3	3.8	26.0	13.8	28.0	13.9	18.0

Table 3. Maximum and minimum air temperatures by month, Malheur Experiment Station, Oregon State University, Ontario, OR, 2010.

	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	52	35	53	39	69	48	79	48	85	59	97	61	100	67	99	62	89	53	86	55	65	43	42	34
Lowest	26	12	34	21	45	23	46	21	50	31	65	40	77	48	70	42	66	37	51	31	24	7	26	9
2010 avg	39	27	44	31	57	33	61	36	67	42	78	52	91	57	88	54	80	45	68	41	47	28	35	20
10-yr avg	36	24	45	27	56	33	64	38	73	47	82	54	94	61	91	57	80	47	65	39	48	29	40	26
67-yr avg	35	20	43	25	55	31	64	37	74	45	82	52	92	58	90	56	80	46	65	37	48	28	37	22

Figure 1. Cumulative growing degree-days (50-86°F) over time for years with lowest (1993) and highest (2003) totals since 1990, compared to 2010 and to the 20-year average (1990-2009), Malheur Experiment Station, Oregon State University, Ontario, OR.

Table 4. Monthly total growing degree- days (50-86°F), Malheur Experiment Station, Oregon State University, Ontario, OR, 1986-2010.

Year	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	total
1986	0	16	85	119	338	639	650	796	296	158	14	0	3111
1987	0	0	43	275	423	547	641	649	486	223	29	2	3318
1988	0	5	51	180	318	585	911	691	376	309	20	0	3446
1989	0	0	13	184	272	549	733	581	389	117	14	0	2852
1990	2	7	79	239	261	497	734	635	585	38	0	0	3077
1991	0	13	16	124	212	389	776	718	436	194	1	0	2879
1992	0	13	106	202	482	574	639	704	385	174	4	0	3283
1993	0	0	23	81	423	358	464	524	408	252	6	0	2539
1994	0	2	92	189	369	523	794	774	509	144	2	0	3398
1995	0	29	32	106	293	433	680	588	472	101	3	10	2747
1996	0	5	53	135	243	446	805	658	364	194	18	2	2923
1997	4	0	81	117	419	509	661	706	481	157	20	0	3154
1998	0	2	52	112	68	571	802	749	515	151	16	4	3042
1999	0	2	43	72	329	459	683	703	416	184	30	0	2921
2000	0	4	36	194	342	536	751	743	368	133	2	0	3109
2001	0	0	63	126	401	488	715	761	472	155	27	0	3208
2002	0	2	32	137	319	562	805	621	437	142	14	2	3073
2003	0	4	72	112	319	594	846	754	448	281	11	2	3443
2004	0	0	115	187	311	607	776	680	365	180	4	0	3225
2005	0	7	59	126	286	419	749	733	383	133	4	0	2899
2006	0	4	22	131	364	599	866	668	394	151	31	0	3230
2007	0	7	99	146	405	551	871	682	398	115	20	0	3294
2008	0	0	13	86	333	504	774	700	387	144	16	2	2959
2009	0	2	27	144	369	486	758	670	535	72	13	0	3074
2010	0	0	45	104	191	439	716	632	423	205	25	0	2780
avg 1986 to 2009	0	5	54	147	327	519	745	688	425	167	13	1	3093

Table 5. Monthly total degree days in the above-ideal (86-104°F) range, Malheur Experiment Station, Oregon State University, Ontario, OR, 1990-2010.

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
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
2004	0	0	18	43	31	2	0	94
2005	0	0	4	43	36	4	0	86
2006	0	5	13	81	23	5	0	128
2007	0	0	14	79	29	5	0	128
2008	0	4	9	41	31	0	0	85
2009	0	4	5	41	32	11	0	94
2010	0	0	2	32	25	0	0	59
mean (1990-2009)	0	2	8	45	33	5	0	94

Table 6. Daily wind-run and monthly totals, Malheur Experiment Station, Oregon State University, Ontario, OR, 2010.

Daily	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
	--------------------------------------------- miles/day ------------------------------------------------
Mean	49	48	95	87	95	88	73	58	48	61	58	41
Max.	197	212	269	248	252	211	137	170	131	199	170	220
Min.	8	18	24	33	31	32	31	16	17	15	8	2
Monthly total	-------------------------------------------- miles/month ------------------------------------------------
2010	1534	1335	2951	2602	2954	2643	2263	1791	1439	1879	1753	1270
10-yr average	1325	1542	2239	2335	1996	1734	1539	1445	1325	1415	1298	1500
62-yr average				2171	1925	1577	1473	1333	1256	1301

Table 7. Daily pan-evaporation and monthly totals, Malheur Experiment Station, Oregon State University, Ontario, OR, 2010.

Totals	Apr	May	Jun	Jul	Aug	Sep	Oct	Total
Daily	-------------------------------------- inches/day ---------------------------------------
Mean	0.19	0.24	0.30	0.40	0.31	0.22	0.15
Max.	0.35	0.39	0.53	0.57	0.55	0.39	0.25
Min.	0.00	0.08	0.02	0.25	0.10	0.11	0.00
Monthly	---------------------------------------- inches/month ------------------------------------
2010	5.78	7.59	9.03	12.52	9.74	6.46	4.54	55.66
10-yr avg	6.33	8.79	10.30	12.36	10.45	7.06	4.13	59.41
62-yr avg	5.70	7.82	9.06	11.30	9.70	6.39	3.34	53.31

Table 8. Total accumulated reference evapotranspiration (ET₀) and estimated crop evapotranspiration (ET_c) (acre-inches/acre), Malheur Experiment Station, Oregon State University, Ontario, OR, 1992-2010.

	ET_o	Alfalfa (mean)	Winter grain	Spring grain	Sugar beet	Onion	Potato	Dry bean	Field corn	Poplar
Year	ET_o	Alfalfa (mean)	Winter grain	Spring grain	Sugar beet	Onion	Potato	Dry bean	Field corn	Yr. 1	Yr. 2	Yr. 3 +
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	31.6	31.9	22.4	29.3	24.3	37.9	45.9
2004	52.8	43.5	27.8	30.6	34.3	30.2	27.9	22.1	28.4	23.3	36.3	44.1
2005	53.8	44.5	26.5	27.0	36.0	32.8	30.2	20.0	29.2	24.3	37.8	45.3
2006	57.7	47.9	24.4	31.4	38.5	33.8	29.4	23.9	30.3	26.3	41.0	49.3
2007	59.0	47.2	27.6	26.7	38.9	33.7	29.7	24.5	30.5	25.7	40.1	48.6
2008	58.0	46.4	28.1	30.4	36.4	32.7	30.0	24.0	30.4	23.3	36.5	44.5
2009	58.1	42.5	26.3	28.4	34.7	28.4	27.6	20.3	26.7	22.6	35.2	42.7
2010	51.5	41.9	21.0	26.8	33.4	28.9	27.7	21.1	26.7	22.2	34.5	41.4
Avg
inches	55.7	42.9	24.8	26.8	34.9	29.9	27.8	21.3	28.0	24.2	37.7	45.5
mm	1416	1089	630	681	886	760	706	541	712	614	957	1156

Table 9. Monthly soil temperature at 4-inch depth, Malheur Experiment Station, Oregon State University, Ontario, OR, 2010.

	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 ----------------------------------------------------------------
2010 avg	33	32		39	38		43	40		47	44		53	50		64	60		72	66		70	65		63	60		57	54		45	43		35	34
Highest	37	36		47	47		46	42		54	52		59	57		72	66		75	71		74	70		67	64		64	61		53	51		37	36
Lowest	31	31		35	34		39	36		41	37		47	44		57	56		66	62		63	58		61	58		50	48		34	34		33	31
10-yr avg	33	32		35	33		43	40		51	46		61	56		69	63		75	69		73	67		66	61		54	51		42	40		35	33
43-yr avg	33	32		37	34		49	40		60	47		72	58		80	66		88	74		86	73		75	63		60	51		44	39		34	33

Table 10. Last and first frost (32°F) dates and number of frost-free days, Malheur Experiment Station, Oregon State University, Ontario, OR, 1990-2010.

Year	Date of last frost	Date of first frost	Total frost-free days
	Spring	Fall
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
2004	April 16	Oct 24	191
2005	April 15	Oct 6	174
2006	April 19	Oct 22	186
2007	May 4	Oct 11	160
2008	May 2	Oct 13	164
2009	May 13	Oct 1	141
2010	May 7	Oct 12	158
1976-2009 Avg	April 28	Oct 6	161

Table 11. Record weather events at the Malheur Experiment Station, Oregon State University, Ontario, OR.

Record event	Measurement	Date
------------------------------------------ Since 1943 ------------------------------------------------
Highest annual precipitation	16.87 inches	1983
Lowest annual precipitation	5.16 inches	1949
Highest monthly precipitation	4.55 inches	May 1998
Highest June precipitation	2.27 inches	June 2009
Highest December precipitation	4.19 inches	Dec 2010
Highest 24-hour precipitation	1.52 inches	Sep 14, 1959
Highest annual snowfall	40 inches	1955
Highest 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. ≥100°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
------------------------------------------ Since 1967 ------------------------------------------------
Lowest soil temperature at 4-inch depth	12°F	Dec 24, 25, and 26, 1990
------------------------------------------ Since 1986 -----------------------------------------------
Most yearly growing degree-days	3,446 degree-days	1988
Fewest yearly growing degree-days	2,539 degree-days	1993
------------------------------------------ Since 1991/1992 ------------------------------------------------
Fewest growing degree-days in March	13	2008
Highest reference evapotranspiration	59.0 inches	2007

Cite as:

Feibert, E.B.G. and C.C. Shock. 2011. 2010 Weather Report. p 1-9. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2010, Department of Crop and Soil Science Ext/CrS 132.

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
2004	1.82	1.54	0.25	0.98	1.70	0.43	0.13	0.64	0.56	2.03	0.93	0.97	11.98
2005	0.41	0.12	1.66	0.80	2.94	1.02	0.22	0.06	0.14	1.38	1.58	3.92	14.25
2006	1.91	0.67	3.33	2.00	0.62	0.45	0.00	0.08	0.55	0.28	1.14	1.76	12.79
2007	0.07	0.95	0.12	0.82	0.47	0.63	0.03	0.15	0.92	0.68	1.07	1.56	7.47
2008	0.50	0.43	0.79	0.14	0.74	0.27	0.43	0.03	1.26	0.44	1.12	1.47	7.62
2009	0.65	0.43	0.86	0.13	1.47	2.27	0.09	1.39	0.02	1.24	0.63	1.82	11.00
2010	2.13	1.19	0.59	1.21	1.18	1.95	0.02	0.86	0.19	1.16	1.09	4.19	15.76
10-yr avg	1.08	0.74	1.06	0.82	1.02	0.68	0.18	0.26	0.45	0.88	0.95	1.65	9.75
67-yr avg	1.26	0.94	0.95	0.78	1.07	0.81	0.22	0.34	0.45	0.74	1.15	1.34	10.05