2001 Boise, Idaho (BOI)

views updated

2001 BOISE, IDAHO (BOI)

Boise is situated in the Boise River Valley about 8 miles below the mouth of a mountain canyon where the valley proper begins. Sheltered by large shade trees and averaging 2,710 feet in elevation, the denser part of the city covers a gentle alluvial slope about 2 miles wide, stretching southwest from the foothills of the Boise Mountains to the river. The Boise Mountains immediately north of the city rise 5,000 to 6,000 feet above sea level in about 8 miles, the slopes partly mantled with sagebrush and then chaparral giving way near the summit to ridges of fir, spruce, and pine. Across the river, the land rises in two irregular steps, or benches, for several miles, finally reaching the low divide between the Boise and Snake Rivers. Downstream the valley widens, merging with the valley of the Snake about 40 miles to the northwest. Once semi–arid, the entire area is now irrigated from the upstream reservoirs.

Although air masses from the Pacific are considerably modified by the time they reach Boise, their influence, particularly in winter, alternates with that of atmospheric developments from other directions. The result is almost a typical upland continental type of climate in summer, while winters are usually tempered by periods of cloudy or stormy and mild weather. Autumns have prolonged periods of near ideal weather, while springtime is noted by changeable weather and varied temperatures. The Boise climate in general may be described as dry and temperate, with sufficient variation to be stimulating.

Summer hot periods rarely last longer than a few days. Temperatures of 100 degrees or higher occur nearly every year.

Winter cold spells with temperatures of 10 degrees or lower generally last longer than the summer hot spells. During cold weather, however, there is ordinarily little wind to add to the discomfort.

The normal precipitation pattern in the Boise area shows a winter high and a very pronounced summer low. Total amounts and intensity are generally greatest near the foothills, dwindling to westward and southward.

Tornadoes are very rare as are destructive force winds. Northwesterly winds, drying and rather raw in character, although of moderate velocity, are common from March through May. Diurnal southeasterly winds, descending from nearby foothills at night, frequently have a moderating effect on winter temperatures. There is an occasional, but moderate, duststorm during the warmer months, usually occurring at times of cold frontal passage.

Relative humidity is low but widespread irrigation maintains humidity several percent above the general dryness of western arid conditions in summer. Thunderstorms occur primarily during spring and summer, with less frequency during fall and occasionally during winter. December and January are the months of heavy fog or low stratus cloud conditions. Only a moderate amount of sunshine is received in the average winter, but protracted periods of clear, sunny weather are the rule in summer. Ice storms are practically unknown.

Based on the 1951–1980 period, the average first occurrence of 32 degrees Fahrenheit in the fall is October 9 and the average last occurrence in the spring is May 8.

NORMALS, MEANS, AND EXTREMES

BOISE, ID (BOI)

LATITUDE:    LONGITUDE:    ELEVATION (FT):    TIME ZONE:    WBAN: 24131

43 33′ 54″ N  116 13′ 12″ W  GRND:  2858  BARO:  2861  MOUNTAIN  (UTC + 7)

ELEMENTPORJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECYEAR
TEMPERATURE FNORMAL DAILY MAXIMUM3036.444.252.961.471.080.990.288.177.064.648.737.762.8
MEAN DAILY MAXIMUM5437.044.452.761.771.180.290.188.377.964.848.738.362.9
HIGHEST DAILY MAXIMUM626371819298109111110102947865111
YEAR OF OCCURRENCE195319921978198719861940196019611945199719991964JUL 1960
MEAN OF EXTREME MAXS.5451.358.568.478.889.497.5102.4100.793.882.465.153.278.5
NORMAL DAILY MINIMUM3021.627.531.936.743.952.157.756.848.239.031.122.539.1
MEAN DAILY MINIMUM5422.127.331.837.044.351.758.057.348.939.030.523.339.3
LOWEST DAILY MINIMUM62-17-15619223135342311-3-25-25
YEAR OF OCCURRENCE195019891971196819821995198619921970197119851990DEC 1990
MEAN OF EXTREME MINS.543.311.519.624.430.338.845.944.934.724.716.56.825.1
NORMAL DRY BULB3029.035.942.449.157.566.574.072.562.651.839.930.150.9
MEAN DRY BULB5429.635.842.249.357.866.074.172.863.451.839.630.751.1
MEAN WET BULB1827.231.737.642.748.453.657.556.450.742.534.726.442.5
MEAN DEW POINT1823.426.329.532.937.941.743.842.338.131.828.922.333.2
NORMAL NO. DAYS WITH:
MAXIMUM 90300.00.00.00.11.36.418.716.03.20.10.00.045.8
MAXIMUM 323010.23.10.20.00.00.00.00.00.00.01.08.022.5
MINIMUM 323025.719.517.08.92.1 *0.00.00.65.816.525.3121.4
MINIMUM 0301.70.50.00.00.00.00.00.00.00.00.11.84.1
H/CNORMAL HEATING DEG. DAYS3011168157014772427562016041475310825861
NORMAL COOLING DEG. DAYS300000912028525288000754
RHNORMAL (PERCENT)3075706052494536374554687556
HOUR 05 LST3079787268676554536066767968
HOUR 11 LST3073665446433932333947647251
HOUR 17 LST3068574335312821232937576841
HOUR 23 LST3078756659565040415060747861
SPERCENT POSSIBLE SUNSHINE5940506268727687858269433864
W/OMEAN NO. DAYS WITH:
HEAVY FOG (VISBY 1/4 MI)635.83.10.80.30.20.10.00.00.10.52.95.519.3
THUNDERSTORMS630.00.30.60.92.82.82.62.41.60.60.30.115.0
CLOUDINESSMEAN:
SUNRISE-SUNSET (OKTAS)
MIDNIGHT-MIDNIGHT (OKTAS)
MEAN NO. DAYS WITH:
CLEAR
PARTLY CLOUDY
CLOUDY
PRMEAN STATION PRESSURE (IN)2927.1927.0927.0027.0027.0027.0027.0027.0027.0027.1027.1027.1927.06
MEAN SEA-LEVEL PRES. (IN)1830.2230.1230.0229.9729.9129.9929.9029.9129.9730.0730.1430.2430.04
WINDSMEAN SPEED (MPH)477.78.79.89.79.28.98.38.07.98.08.17.88.5
PREVAIL. DIR (TENS OF DEGS)3113131331313131131313131313
MAXIMUM 2-MINUTE:
SPEED (MPH)633363246324036393335394546
DIR. (TENS OF DEGS)31303231273134301928113131
YEAR OF OCCURRENCE199619992000199819971997199719991997200120012000APR 1998
MAXIMUM 5-SECOND:
SPEED (MPH)638434052415147484144456363
DIR. (TENS OF DEGS)31263232273017141828113030
YEAR OF OCCURRENCE199620001997199819971997199820001997200120012000DEC 2000
PRECIPITATIONNORMAL (IN)301.451.071.291.241.080.810.350.430.800.751.481.3612.11
MAXIMUM MONTHLY (IN)623.873.703.463.044.403.411.622.372.932.593.364.234.40
YEAR OF OCCURRENCE197019861989195519981941198219681986200019881983MAY 1998
MINIMUM MONTHLY (IN)620.120.180.170.09T0.010.000.000.000.000.140.090.00
YEAR OF OCCURRENCE194919971994194919921966194719981987198819761976AUG 1998
MAXIMUM IN 24 HOURS (IN)621.481.001.651.272.052.240.941.611.741.060.881.162.24
YEAR OF OCCURRENCE195319511981196919901958196019791976200019711955JUN 1958
NORMAL NO. DAYS WITH:
PRECIPITATION 0.013011.89.79.78.27.25.62.83.34.25.610.411.489.9
PRECIPITATION 1.00300.00.0*0.10.10.10.0**0.00.00.00.3
SNOWFALLNORMAL (IN)306.32.71.41.00.20.00.00.00.00.12.76.921.3
MAXIMUM MONTHLY (IN)6221.425.211.98.04.0TTTT2.718.626.226.2
YEAR OF OCCURRENCE196419491951196719641995199519891998197119851983DEC 1983
MAXIMUM IN 24 HOURS (IN)628.513.06.47.24.0TTTT1.76.59.813.0
YEAR OF OCCURRENCE195019491952196919641995199519891998197119641996FEB 1949
MAXIMUM SNOW DEPTH (IN)5312961000000111313
YEAR OF OCCURRENCE198219491952197519851985DEC 1985
NORMAL NO. DAYS WITH:
SNOWFALL 1.0302.10.90.40.30.*0.00.00.00.00.11.02.77.5
PRECIPITATION (inches) 2001 BOISE, ID (BOI)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
19722.150.911.500.620.320.900.210.051.110.641.111.7911.31
19731.140.420.651.490.740.190.070.030.821.152.442.2311.37
19741.350.661.500.670.100.600.530.22T1.450.671.719.46
19750.592.621.921.530.880.780.820.480.011.990.781.2913.69
19761.491.310.721.600.461.661.150.952.110.520.140.0912.20
19770.650.570.860.191.801.260.410.731.200.211.862.4612.20
19782.371.501.432.340.360.560.480.240.89T1.060.6011.83
19791.931.200.481.601.280.180.011.810.041.501.300.7412.07
19801.561.292.141.203.770.580.03T1.590.301.261.4915.21
19811.201.022.761.930.950.770.230.130.360.972.242.7215.28
19821.421.541.390.790.390.351.620.191.381.741.101.9213.83
19831.671.262.702.291.930.171.160.280.650.561.874.2318.77
19840.800.861.431.621.061.470.231.240.690.852.360.6313.24
19850.200.550.970.901.520.370.850.041.810.841.851.2411.14
19860.983.702.011.551.100.350.170.072.930.331.000.1214.31
19870.731.242.010.380.690.580.700.110.00T1.001.058.49
19881.300.431.451.801.330.470.020.090.240.003.360.8111.30
19891.141.153.460.460.210.080.030.781.201.240.590.1010.44
19900.840.790.772.144.070.110.420.390.500.450.610.9812.07
19910.960.460.551.651.570.640.370.040.210.911.760.359.47
19920.360.920.170.66T2.070.03T0.300.901.370.897.67
19931.650.962.452.090.922.100.520.24T0.470.380.9812.76
19941.280.900.171.251.010.240.10T0.100.781.781.799.40
19952.100.511.511.032.360.880.590.060.220.422.202.1414.02
19961.331.071.971.471.670.210.12T0.460.681.713.4314.12
19972.740.180.521.891.141.350.450.270.670.550.680.6511.09
19982.731.390.990.814.401.210.490.001.960.110.971.6516.71
19991.401.960.750.611.100.47T0.290.000.111.000.908.59
20001.512.061.691.010.830.140.030.100.602.590.680.8012.04
20011.070.491.071.200.270.320.15T0.440.861.521.158.54
POR=102 YRS1.471.251.301.211.250.870.200.200.500.901.291.3011.74
AVERAGE TEMPERATURE (F) 2001 BOISE, ID (BOI)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
197230.936.545.546.760.667.673.574.558.851.740.523.850.9
197330.739.443.049.160.567.675.673.063.152.441.738.452.9
197429.438.742.649.755.471.773.871.765.352.241.733.252.1
197528.236.941.544.556.264.478.370.065.552.339.531.450.7
197632.234.237.147.359.362.673.167.764.150.840.929.349.9
197719.033.839.854.153.770.272.773.662.053.239.637.350.8
197837.038.248.748.554.364.572.869.961.452.836.727.051.0
197916.234.343.248.757.866.774.171.267.354.434.735.850.4
198030.339.841.152.657.262.672.967.262.651.639.833.150.9
198133.936.844.550.354.763.271.074.263.748.744.035.351.7
198224.830.041.345.254.965.870.172.760.450.936.031.548.6
198335.941.544.647.156.563.869.474.960.853.842.023.251.1
198421.230.241.945.954.861.774.275.560.146.939.122.947.9
198519.125.836.051.658.567.277.769.256.248.427.712.645.8
198629.441.048.048.359.172.069.675.957.452.640.428.051.8
198727.837.644.256.062.270.271.270.065.654.940.732.952.8
198826.137.842.652.757.970.774.671.661.759.940.727.051.9
198924.723.243.753.156.368.577.070.063.351.239.430.450.1
199034.234.144.354.755.766.976.274.069.951.041.218.151.7
199124.441.643.048.354.962.675.776.665.851.837.431.751.2
199233.142.148.954.964.369.871.473.963.454.434.528.553.3
199324.828.941.748.163.161.965.068.663.053.232.833.348.7
199432.734.746.152.661.067.977.076.166.850.332.630.452.4
199536.241.543.648.256.963.973.471.265.749.244.433.152.3
199632.535.144.250.055.466.776.774.861.852.441.336.352.3
199732.136.845.448.962.966.072.875.667.752.043.031.252.9
199838.940.244.349.956.363.479.276.769.851.743.730.753.7
199935.337.043.847.555.866.373.775.164.054.346.931.952.6
200034.241.743.454.359.768.676.175.963.052.332.731.152.8
200127.233.945.948.161.467.374.378.768.453.544.030.752.8
POR=102 YRS29.735.642.449.857.865.574.372.463.052.340.131.551.2

REFERENCE NOTES:

PAGE 1:

THE TEMPERATURE GRAPH SHOWS NORMAL MAXIMUM AND NORMAL MINIMUM DAILY TEMPERATURES (SOLID CURVES) AND THE ACTUAL DAILY HIGH AND LOW TEMPERATURES (VERTICAL BARS).

PAGE 2 AND 3:

H/C INDICATES HEATING AND COOLING DEGREE DAYS.

RH INDICATES RELATIVE HUMIDITY

W/O INDICATES WEATHER AND OBSTRUCTIONS

S INDICATES SUNSHINE.

PR INDICATES PRESSURE.

CLOUDINESS ON PAGE 3 IS THE SUM OF THE CEILOMETER AND SATELLITE DATA NOT TO EXCEED EIGHT EIGHTHS (OKTAS).

GENERAL:

T INDICATES TRACE PRECIPITATION, AN AMOUNT GREATER THAN ZERO BUT LESS THAN THE LOWEST REPORTABLE VALUE.

+ INDICATES THE VALUE ALSO OCCURS ON EARLIER DATES.

BLANK ENTRIES DENOTE MISSING OR UNREPORTED DATA.

NORMALS ARE 30–YEAR AVERAGES (1961–1990).

ASOS INDICATES AUTOMATED SURFACE OBSERVING SYSTEM.

PM INDICATES THE LAST DAY OF THE PREVIOUS MONTH.

POR (PERIOD OF RECORD) BEGINS WITH THE JANUARY DATA MONTH AND IS THE NUMBER OF YEARS USED TO COMPUTE THE MEAN. INDIVIDUAL MONTHS WITHIN THE POR MAY BE MISSING.

WHEN THE POR FOR A NORMAL IS LESS THAN 30 YEARS, THE NORMAL IS PROVISIONAL AND IS BASED ON THE NUMBER OF YEARS INDICATED.

0.* OR * INDICATES THE VALUE OR MEAN–DAYS–WITH IS BETWEEN 0.00 AND 0.05.

CLOUDINESS FOR ASOS STATIONS DIFFERS FROM THE NON–ASOS OBSERVATION TAKEN BY A HUMAN OBSERVER. ASOS STATION CLOUDINESS IS BASED ON TIME–AVERAGED CEILOMETER DATA FOR CLOUDS AT OR BELOW 12,000 FEET AND ON SATELLITE DATA FOR CLOUDS ABOVE 12,000 FEET.

THE NUMBER OF DAYS WITH CLEAR, PARTLY CLOUDY, AND CLOUDY CONDITIONS FOR ASOS STATIONS IS THE SUM OF THE CEILOMETER AND SATELLITE DATA FOR THE SUNRISE TO SUNSET PERIOD.

GENERAL CONTINUED:

CLEAR INDICATES 0–2 OKTAS, PARTLY CLOUDY INDICATES 3–6 OKTAS, AND CLOUDY INDICATES 7 OR 8 OKTAS. WHEN AT LEAST ONE OF THE ELEMENTS (CEILOMETER OR SATELLITE) IS MISSING, THE DAILY CLOUDINESS IS NOT COMPUTED.

WIND DIRECTION IS RECORDED IN TENS OF DEGREES (2 DIGITS) CLOCKWISE FROM TRUE NORTH. "00" INDICATES CALM. "36" INDICATES TRUE NORTH.

RESULTANT WIND IS THE VECTOR AVERAGE OF THE SPEED AND DIRECTION.

AVERAGE TEMPERATURE IS THE SUM OF THE MEAN DAILY MAXIMUM AND MINIMUM TEMPERATURE DIVIDED BY 2.

SNOWFALL DATA COMPRISE ALL FORMS OF FROZEN PRECIPITATION, INCLUDING HAIL.

A HEATING (COOLING) DEGREE DAY IS THE DIFFERENCE BETWEEN THE AVERAGE DAILY TEMPERATURE AND 65 F.

DRY BULB IS THE TEMPERATURE OF THE AMBIENT AIR.

DEW POINT IS THE TEMPERATURE TO WHICH THE AIR MUST BE COOLED TO ACHIEVE 100 PERCENT RELATIVE HUMIDITY.

WET BULB IS THE TEMPERATURE THE AIR WOULD HAVE IF THE MOISTURE CONTENT WAS INCREASED TO 100 PERCENT RELATIVE HUMIDITY.

ON JULY 1, 1996, THE NATIONAL WEATHER SERVICE BEGAN USING THE "METAR" OBSERVATION CODE THAT WAS ALREADY EMPLOYED BY MOST OTHER NATIONS OF THE WORLD. THE MOST NOTICEABLE DIFFERENCE IN THIS ANNUAL PUBLICATION WILL BE THE CHANGE IN UNITS FROM TENTHS TO EIGHTS (OKTAS) FOR REPORTING THE AMOUNT OF SKY COVER.

HEATING DEGREE DAYS (base 65 F) 2001 BOISE, ID (BOI)
YEARJULAUGSEPOCTNOVDECJANFEBMARAPRMAYJUNTOTAL
1972-7311022240672712701056708673470182915816
1973-744131033826928171099728687452304425323
1974-751011533916899831132782721607275765730
1975-7662174399759103510138868585241891325896
1976-77336764347201097141886877234235876131
1977-78832145362758853859744500488329745152
1978-7953817337084111711503855668481241726418
1979-80522632690389910707257363672571335449
1980-81041104409750983957783631432315975502
1981-821551374976249151240974729586312866120
1982-832721824328631030897653622530309825629
1983-843801453386821290135310047105663281626616
1984-8508204557771129914121093895398226536916
1985-86026259509111316191097668522499280156607
1986-8735225937673311411149761639287140415563
1987-882318863067229901198780686359261595488
1988-8945157178724116912421166656356276305963
1989-90029974217591064951858633303286825483
1990-9161026430710144912526516764933061006109
1991-920055409822102698265749230892544897
1992-936401183409071124123910047155011401556289
1993-945345124367960975993839579378148645525
1994-95913444996710668876526574992551115587
1995-96523864856109841000859636447292555482
1996-97161624057038831013783601473128415199
1997-98180614106511040803684635452270855109
1998-9900514086351058914778652520311955422
1999-008131013245351017949673663315179414818
2000-014012838996010441165867585504191695906
2001-60233556261056
COOLING DEGREE DAYS (base 65 F) 2001 BOISE, ID (BOI)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
197200006212928330340000817
197300005117734126951100890
197400001325228922671000851
197500001064426182961100789
19760000196626313055200535
1977000201017025530661000822
1978001066425420072000597
1979000027129293199101300752
19800003256825111738200504
19810001352205296101000658
19820000211719424850000611
19830000555018031326000624
19840000197029134064200786
19850002281254021654000726
1986000110323518434837000908
19870002361202223180111000800
1988000046237308215662400896
198900061414037619156000783
199000035145357293180600989
1991000003633736885600832
19920001176202208321772000915
1993000086686116271800456
19940001530156386354960001037
199500001283272225114000706
199600004111372314732200896
1997000071802663371511300918
199800049424493712013001079
199900003214228233480100871
200000032215535434774200957
20010004851463034331317001109
SNOWFALL (inches) 2001 BOISE, ID (BOI)
YEARJULAUGSEPOCTNOVDECJANFEBMARAPRMAYJUNTOTAL
1972-730.00.00.0TT12.67.30.30.6T0.00.020.8
1973-740.00.00.00.08.84.56.02.45.7T0.00.027.4
1974-750.00.00.00.00.94.65.46.32.22.60.90.022.9
1975-760.00.00.0T3.94.26.36.73.90.20.00.025.2
1976-770.00.00.00.0T1.17.23.52.9TT0.014.7
1977-780.00.00.0T4.74.41.67.3TTT0.018.0
1978-790.00.00.00.00.23.111.94.30.80.2T0.020.5
1979-800.00.00.00.06.61.43.80.82.7T0.00.015.3
1980-810.00.00.00.03.21.73.60.7T0.50.00.09.7
1981-820.00.00.00.02.811.112.21.43.61.40.00.032.5
1982-830.00.00.00.02.16.41.60.9TT0.80.011.8
1983-840.00.00.00.02.226.24.34.4T0.3T0.037.4
1984-850.00.00.0T0.27.72.65.31.51.00.00.018.3
1985-860.00.00.0T18.612.63.94.40.0T0.00.039.5
1986-870.00.00.00.05.90.90.50.6T0.00.00.07.9
1987-880.00.00.00.00.53.03.90.32.91.20.00.011.8
1988-890.00.00.00.02.510.88.00.7TT0.00.022.0
1989-900.0T0.0T0.4T5.26.50.4TT0.012.5
1990-910.00.00.00.00.115.71.5T1.2T0.00.018.5
1991-920.00.00.01.12.8T0.3T0.0T0.00.04.2
1992-930.00.00.0T3.65.714.610.40.2TT0.034.5
1993-940.00.00.00.01.90.22.83.8TT0.00.08.7
1994-950.00.00.00.08.88.51.55.71.2TTT25.7
1995-96T0.00.00.00.25.96.76.91.8TT0.021.5
1996-970.00.00.0TT13.03.4T0.3T0.00.016.7
1997-980.00.00.00.00.00.64.21.41.1T0.00.07.3
1998-99T0.0T0.0T8.81.75.76.70.40.00.023.3
1999-000.00.00.00.00.92.76.22.12.30.0T0.014.2
2000-010.00.00.00.04.01.68.93.11.3T0.00.018.9
2001-0.00.00.00.03.59.9
POR=61 YRSTT0.00.12.35.76.33.51.80.60.1T20.4

More From encyclopedia.com

About this article

2001 Boise, Idaho (BOI)

Updated About encyclopedia.com content Print Article

You Might Also Like

    NEARBY TERMS

    2001 Boise, Idaho (BOI)