2001 Duluth, Minnesota (DLH)

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2001 DULUTH, MINNESOTA (DLH)

Duluth, Minnesota is located at the western tip of Lake Superior. The city, about 20 miles long, lies at the base of a range of hills that rise abruptly to 600–800 feet above the level of Lake Superior. The range runs in a northeast and southwest direction. Two or 3 miles from the lake the land becomes a slightly rolling plateau.

Duluth in the summer is known as the Air Conditioned City. Being situated below high terrain and along the lake, any easterly component winds automatically cool the city. However, with westerly flow in the summer, the wind generally abates at night, thus, allowing cool lake air to move back into the city area near the lake.

An important influence on the climate is the passage of a succession of high and low pressure systems west and east. The proximity of Lake Superior, which is the largest and coldest of the Great Lakes, modifies the local weather. Summer temperatures are cooler and winter temperatures are warmer. The lake effect at Duluth is most prevalent when low pressure systems pass to the south creating easterly winds. In the summer, warm, moist air flowing over the cold lake surface has a stabilizing effect that results in cool, cloudy weather over Duluth. However, during the winter cold air flowing over the warm open lake surface absorbs moisture that is later precipitated over Duluth as snow. The lake effect is further reflected from the low frequency of severe storms such as wind, hail, tornadoes, freezing rain (glaze), and blizzards when compared to other areas that are a further distance from the lake.

Easterly component winds at Duluth occur 40 to 50 percent of the time from March through August and 20 to 25 percent of the time from November through February. During the winter 60 to 70 percent of the winds are from a westerly component.

The climate of Duluth is predominantly continental with significant local Lake Superior effects. Duluth averages 143 days between the last occurrence of 32 degrees in mid–May and the first in early October. At the Duluth Airport about six miles away from the lake, the average first and last occurrences of 32 degrees are late May and late September, giving a freeze–free period of 123 days.

Fall colors throughout this area are outstanding. Reds, yellows, browns, and combinations of these are an experience to see. Recreation is superb from December through March for cross–country and down–hill skiing and snowmobiling. The snow is dry.

Ice in the harbor forms about mid–November and generally is gone by mid–April. The shipping season can vary from year to year depending on temperatures and the winds that move the ice around. In most years there is little or no shipping during February and March on Lake Superior.

NORMALS, MEANS, AND EXTREMES

DULUTH, MN (DLH)

LATITUDE:    LONGITUDE:    ELEVATION (FT):    TIME ZONE:    WBAN: 14913

46 50′ 38″ N  92 11′ 39″ W  GRND: 1426  BARO: 1429  CENTRAL (UTC + 6)

ELEMENTPORJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECYEAR
TEMPERATURE FNORMAL DAILY MAXIMUM3016.221.732.948.261.971.077.173.963.852.335.220.747.9
MEAN DAILY MAXIMUM5416.822.532.647.961.870.676.174.064.152.635.021.748.0
HIGHEST DAILY MAXIMUM6052557888909497979586715597
YEAR OF OCCURRENCE194220001946195219861995198819471976195319991962JUL 1988
MEAN OF EXTREME MAXS.5436.241.251.370.781.885.988.687.581.473.454.839.566.0
NORMAL DAILY MINIMUM30-2.22.815.728.939.648.555.153.344.535.121.54.929.0
MEAN DAILY MINIMUM54-1.53.615.129.039.948.354.553.244.835.121.26.029.1
LOWEST DAILY MINIMUM60-39-39-29-517273532228-23-34-39
YEAR OF OCCURRENCE197219961989197519671972198819861942197619641983FEB 1996
MEAN OF EXTREME MINS.54-26.8-21.1-9.812.126.735.642.740.829.420.00.1-17.811.0
NORMAL DRY BULB307.012.324.438.650.859.866.163.754.243.728.412.838.5
MEAN DRY BULB547.713.123.838.550.759.665.363.754.443.928.114.038.6
MEAN WET BULB1610.114.423.634.245.854.659.659.150.838.824.513.235.7
MEAN DEW POINT165.48.617.126.138.549.955.855.646.833.320.29.130.5
NORMAL NO. DAYS WITH:
MAXIMUM 90300.00.00.00.00.10.21.10.80.20.00.00.02.4
MAXIMUM 323027.922.315.12.00.00.00.00.00.00.611.826.5106.2
MINIMUM 323031.027.828.920.25.60.40.0*2.612.425.630.8185.3
MINIMUM 03017.412.94.60.10.00.00.00.00.00.01.512.448.9
H/CNORMAL HEATING DEG. DAYS3017981476125979244517060113329660109816189818
NORMAL COOLING DEG. DAYS30000001494720000180
RHNORMAL (PERCENT)3072706964637071747671757671
HOUR 00 LST3074737470717982848477787877
HOUR 06 LST3076767876768184888782817980
HOUR 12 LST3069656356535959626462707463
HOUR 18 LST3069646254525859646866727464
SPERCENT POSSIBLE SUNSHINE4748535556575865615246353952
W/OMEAN NO. DAYS WITH:
HEAVY FOG(VISBY 1/4 MI)532.32.53.63.65.26.65.46.45.54.53.33.252.1
THUNDERSTORMS590.10.00.61.73.56.77.96.93.91.30.40.133.1
CLOUDINESSMEAN:
SUNRISE-SUNSET (OKTAS)485.45.25.45.45.35.34.74.75.25.36.05.65.3
MIDNIGHT-MIDNIGHT (OKTAS)325.05.05.25.04.84.84.34.34.75.05.75.44.9
MEAN NO. DAYS WITH:
CLEAR497.47.37.06.26.25.16.77.26.36.44.46.076.2
PARTLY CLOUDY497.06.26.97.99.611.012.711.98.47.65.55.8100.5
CLOUDY4916.714.717.015.915.213.910.911.314.616.419.518.6184.7
PRMEAN STATION PRESSURE(IN)2828.5028.5028.5028.4028.4028.4028.5028.5028.5028.5028.4128.5128.47
MEAN SEA-LEVEL PRES. (IN)1630.0630.0730.0629.9729.9630.0029.9630.0130.0130.0130.0230.0830.02
WINDSMEAN SPEED (MPH)4311.611.612.012.611.910.59.79.510.611.512.211.611.3
PREVAIL. DIR (TENS OF DEGS)2730310909091110113031303130
MAXIMUM 2-MINUTE:
SPEED (MPH)537374743393339463338444147
DIR. (TENS OF DEGS)33090820280928292635082808
YEAR OF OCCURRENCE200119991998199819982000199920011998199919982001MAR 1998
MAXIMUM 5-SECOND:
SPEED (MPH)544465757494647624049555662
DIR. (TENS OF DEGS)33070820302328292701093129
YEAR OF OCCURRENCE200119991998199820001999199920011998199919981999AUG 2001
PRECIPITATIONNORMAL (IN)301.220.801.912.253.033.823.613.993.842.491.801.2430.00
MAXIMUM MONTHLY (IN)604.702.725.128.187.678.048.7410.319.387.535.083.7010.31
YEAR OF OCCURRENCE196919981965200119621986199919721991194920001968AUG 1972
MINIMUM MONTHLY (IN)600.140.130.220.240.150.550.970.710.190.130.190.130.13
YEAR OF OCCURRENCE196119881959198719761995194719701952194419761997DEC 1997
MAXIMUM IN 24 HOURS (IN)521.741.382.382.603.254.053.685.793.772.902.642.125.79
YEAR OF OCCURRENCE197519651977200119791958198719781972197319681950AUG 1978
NORMAL NO. DAYS WITH:
PRECIPITATION 0.013012.19.410.910.411.812.311.211.812.19.810.511.7134.0
PRECIPITATION 1.00300.10.00.20.20.40.81.11.20.90.60.30.15.9
SNOWFALLNORMAL (IN)3017.210.314.16.30.60.00.00.00.*1.311.416.177.3
MAXIMUM MONTHLY (IN)5846.832.145.531.58.10.2TT2.49.750.144.350.1
YEAR OF OCCURRENCE196920011965195019541945199219951991199519911950NOV 1991
MAXIMUM IN 24 HOURS (IN)5816.317.019.411.64.30.2TT2.47.924.125.425.4
YEAR OF OCCURRENCE199419481965198319541945199219951991196619911950DEC 1950
MAXIMUM SNOW DEPTH (IN)5342384841900006303248
YEAR OF OCCURRENCE19691969196519651950196619911983MAR 1965
NORMAL NO. DAYS WITH:
SNOWFALL 1.0304.23.34.01.80.20.00.00.00.00.42.94.521.3
PRECIPITATION (inches) 2001 DULUTH, MN (DLH)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
19722.281.471.452.172.003.706.7110.315.300.831.372.0239.61
19730.670.291.541.353.812.432.368.464.284.561.610.6932.05
19740.970.820.782.073.094.074.853.790.981.571.361.1525.50
19753.690.762.592.211.445.592.262.522.321.204.190.6429.41
19761.571.053.670.730.156.162.601.841.840.480.190.3920.67
19770.360.474.431.273.503.973.913.265.973.202.371.3134.02
19780.520.350.471.963.492.967.677.491.520.771.271.1929.66
19790.761.893.581.156.014.335.452.102.013.010.470.1630.92
19801.550.561.020.410.822.353.945.346.611.640.700.6325.57
19810.321.501.054.481.155.833.262.842.423.590.960.9728.37
19822.020.482.062.064.301.976.211.604.195.073.081.1934.23
19831.340.492.052.282.122.003.513.375.572.325.011.9732.03
19840.780.610.542.341.835.701.331.963.825.190.821.9126.83
19850.390.661.852.354.443.184.163.916.021.762.330.7831.83
19860.660.740.884.112.598.044.585.296.260.662.010.4536.27
19870.690.310.600.244.020.835.461.872.930.961.260.6719.84
19880.780.132.550.443.964.561.146.826.181.053.441.1232.17
19891.870.341.492.113.503.811.095.024.401.021.010.6326.29
19900.510.513.353.761.484.832.425.396.493.510.650.4933.39
19910.520.551.173.906.115.645.332.499.382.854.890.6143.44
19920.600.580.842.872.875.043.644.133.901.131.841.2328.67
19931.790.380.442.424.746.955.753.631.810.562.601.2832.35
19941.850.621.114.111.914.542.203.455.612.272.530.3330.53
19951.381.041.972.194.130.555.736.673.024.241.841.5434.30
19961.351.100.501.471.615.108.372.925.343.083.950.8635.65
19970.940.231.481.071.905.174.331.261.752.290.430.1320.98
19980.362.721.841.422.216.131.722.593.334.213.421.5731.52
19990.870.640.762.962.934.728.747.415.802.350.700.2338.11
20000.771.082.641.383.074.183.504.422.022.275.080.9331.34
20011.251.760.698.183.493.061.893.311.412.422.210.5530.22
POR=98 YRS1.120.931.642.273.104.053.783.513.392.251.771.0928.90
AVERAGE TEMPERATURE (F) 2001 DULUTH, MN (DLH)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
19720.26.417.933.353.558.461.261.950.038.925.97.234.6
197311.613.731.838.347.859.164.865.553.648.227.911.739.5
19745.611.020.637.946.658.667.160.147.942.829.219.537.2
19759.612.018.231.053.357.968.762.050.946.731.311.837.8
19764.720.722.042.650.663.266.164.955.337.122.14.537.8
1977-.217.231.444.457.460.065.958.653.244.328.011.339.3
19785.110.525.638.354.860.264.763.657.344.926.210.138.4
19790.65.023.034.547.259.866.162.056.943.029.422.237.5
19808.710.719.741.454.959.567.663.652.938.930.111.638.3
198111.916.328.339.250.258.765.564.352.940.534.714.839.8
1982-3.210.620.835.752.854.864.560.854.345.124.419.636.7
198313.221.125.635.146.759.969.669.756.644.931.61.839.7
19847.123.018.742.450.561.466.667.751.945.728.413.239.7
19856.511.630.342.154.956.564.659.752.142.719.93.037.0
198611.711.528.542.151.858.964.760.852.743.424.018.839.1
198715.323.731.646.153.163.167.663.557.239.432.220.442.8
19884.86.224.440.156.062.870.064.555.438.628.913.538.8
198914.33.418.936.851.758.468.664.855.944.423.24.137.0
199018.714.927.140.248.361.564.664.156.242.131.412.640.1
19915.919.426.142.754.761.763.866.353.040.422.015.939.3
199216.721.225.936.253.856.359.460.553.841.727.315.939.1
199311.914.527.137.250.357.163.665.049.540.024.417.038.1
1994-2.16.528.639.653.862.564.562.558.547.233.621.339.7
199513.711.728.234.752.465.166.867.455.143.720.612.139.3
19962.211.919.433.748.260.462.165.456.243.621.611.236.3
19977.014.523.535.745.862.263.861.057.543.924.922.738.5
199816.429.025.444.155.958.865.767.159.345.932.118.743.2
19999.321.327.841.453.660.667.663.554.542.336.219.741.5
200010.321.433.438.152.956.064.664.753.946.928.64.439.6
200117.47.824.539.852.860.965.767.055.443.439.522.241.4
POR=98 YRS8.612.924.338.449.658.765.263.755.144.128.614.738.7

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 ALBUQUERQUE, NM (ABQ)
YEARJULAUGSEPOCTNOVDECJANFEBMARAPRMAYJUNTOTAL
1972-730314244740925102081160744011334920
1973-7400432576069559637543732552944239
1974-7502682125931020105174861444914364906
1975-7600472566649059796226343049914511
1976-77003536772698510846756692506104852
1977-7800119255175787071345421517523930
1978-790020167521945988665509241100124168
1979-80002314871584076359557737913924181
1980-810063356407528276115751976224007
1981-820032805347548957095382689404075
1982-83002331465894192270355643912704683
1983-8400111985928759487145593622234284
1984-8500514116319039607445362207474537
1985-8600612285818427276104312498083817
1986-87005131368088210047176533008124683
1987-8800213358991493760555129010324126
1988-8905391185799599096403731333103786
1989-90001026055191893473550123310304245
1990-910014202595101390356358126360124206
1991-9200211886458519946514931705354071
1992-930081287529917786244962386934087
1993-9400152846428538276764532185204020
1994-950012516107417934354333206703651
1995-9600371654197417875405582391203498
1996-97006629757580997367640336648124225
1997-980092786359948347275583765144466
1998-990002255498167445844353329853788
1999-0000232034479027405715281843203630
2000-0100163027608589616195092183534281
2001-001134508881
COOLING DEGREE DAYS (base 65 F) 2001 DULUTH, MN (DLH)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
1972000082224590000113
1973000001728418000175
19740000019115150000149
19750000218168410000229
197600000537511726000271
1977000012248060000122
197800001734706439000224
19790000425953015000169
198000002546126403000240
198100002297486000155
1982000000583618000112
1983000004217916542000428
19840000413961334000250
1985000094542015000102
19860000131874260000131
198700001362121607000263
198800002783183894000386
19890000017147807000251
19900007032707316000198
199100002035691178000249
199200001318937330083
199300000836760000120
19940000113652438000150
1995000071071059914400336
19960000044255821000148
1997000002767378000139
19980000812819332000226
1999000012331273520000227
2000000021069519000141
200100000499611717000279
SNOWFALL (inches) 2001 DULUTH, MN (DLH)
YEARJULAUGSEPOCTNOVDECJANFEBMARAPRMAYJUNTOTAL
1972-730.00.0T0.56.720.09.23.02.12.81.50.045.8
1973-740.00.00.0T7.615.713.415.315.15.21.00.073.3
1974-750.00.00.30.84.519.132.712.330.30.4T0.0100.4
1975-760.00.00.00.125.77.820.68.826.40.0T0.089.4
1976-770.00.00.00.82.77.88.85.115.30.10.00.040.6
1977-780.00.00.01.716.012.013.511.48.36.80.00.069.7
1978-790.00.00.0T10.120.811.923.317.04.21.40.088.7
1979-800.00.00.00.86.02.021.910.312.61.5T0.055.1
1980-810.00.00.01.31.67.14.713.34.24.3T0.036.5
1981-820.00.0T1.412.515.534.28.017.86.30.00.095.7
1982-830.00.00.00.816.021.415.79.09.923.7T0.096.5
1983-840.00.0TT37.732.120.04.09.93.30.30.0107.3
1984-850.00.0T3.52.48.215.312.026.70.10.00.068.2
1985-860.00.00.72.334.118.811.510.311.40.2T0.089.3
1986-870.00.00.01.88.27.311.25.16.70.3T0.040.6
1987-880.00.00.03.95.811.316.72.313.70.10.00.053.8
1988-890.00.00.00.324.320.731.25.317.619.00.70.0119.1
1989-900.0T0.00.68.414.25.515.011.62.40.6T58.3
1990-910.00.00.03.25.113.511.49.79.58.52.90.063.8
1991-920.00.02.44.350.112.99.310.60.79.70.00.0100.0
1992-93T0.0T5.129.415.524.910.05.83.5T0.094.2
1993-940.00.0T0.628.515.135.37.913.010.00.0T110.4
1994-950.00.00.00.215.56.212.817.620.916.2T0.089.4
1995-960.0T0.19.720.425.934.021.311.412.6T
1996-9715.941.735.58.923.61.70.10.0
1997-980.00.00.01.216.96.029.99.614.22.30.0T80.1
1998-990.0T0.0T15.712.818.913.517.811.50.00.090.2
1999-000.00.00.00.06.24.416.513.39.55.6T0.055.5
2000-010.00.00.0T17.519.214.932.17.97.70.00.099.3
2001-0.00.00.02.011.47.3
POR=57 YRSTT0.11.512.915.017.611.713.36.61.0T79.7

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2001 Duluth, Minnesota (DLH)