2001 Richmond, Virginia (RIC)

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2001 RICHMOND, VIRGINIA (RIC)

Richmond is located in east–central Virginia at the head of navigation on the James River and along a line separating the Coastal Plains (Tidewater Virginia) from the Piedmont. The Blue Ridge Mountains lie about 90 miles to the west and the Chesapeake Bay 60 miles to the east. Elevations range from a few feet above sea level along the river to a little over 300 feet in parts of the western section of the city.

The climate might be classified as modified continental. Summers are warm and humid and winters generally mild. The mountains to the west act as a partial barrier to outbreaks of cold, continental air in winter. The cold winter air is delayed long enough to be modified, then further warmed as it subsides in its approach to Richmond. The open waters of the Chesapeake Bay and Atlantic Ocean contribute to the humid summers and mild winters. The coldest weather normally occurs in late December and January, when low temperatures usually average in the upper 20s, and the high temperatures in the upper 40s. Temperatures seldom lower to zero, but there have been several occurrences of below zero temperatures. Summertime high temperatures above 100 degrees are not uncommon, but do not occur every year.

Precipitation is rather uniformly distributed throughout the year. However, dry periods lasting several weeks do occur, especially in autumn when long periods of pleasant, mild weather are most common. There is considerable variability in total monthly amounts from year to year. Snow usually remains on the ground only one or two days at a time. Ice storms (freezing rain or glaze) are not uncommon, but they are seldom severe enough to do any considerable damage. A notable exception was the spectacular glaze storm of January 27–28, 1943, when nearly 1 inch of ice accumulation caused heavy damage to trees and overhead transmission lines.

The James River reaches tidewater at Richmond where flooding may occur in every month of the year, most frequently in March and least in July. Hurricanes and tropical storms have been responsible for most of the flooding during the summer and early fall months. Hurricanes passing near Richmond have produced record rainfalls. In 1955, three hurricanes brought record rainfall to Richmond within a six–week period. The most noteworthy of these were Hurricanes Connie and Diane that brought heavy rains five days apart.

Damaging storms occur mainly from snow and freezing rain in winter and from hurricanes, tornadoes, and severe thunderstorms in other seasons. Damage may be from wind, flooding, or rain, or from any combination of these. Tornadoes are infrequent but some notable occurrences have been observed within the Richmond area.

Based on the 1951–1980 period, the average first occurrence of 32 degrees Fahrenheit in the fall is October 26 and the average last occurrence in the spring is April 10.

NORMALS, MEANS, AND EXTREMES

RICHMOND, VA (RIC)

LATITUDE:    LONGITUDE:    ELEVATION (FT):    TIME ZONE:    WBAN: 13740

37 30′ 40″ N  77 19′ 24″ W  GRND: 164  BARO: 167  EASTERN (UTC + 5)

ELEMENTPORJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECYEAR
TEMPERATURE FNORMAL DAILY MAXIMUM3045.749.259.570.077.885.188.487.180.970.761.350.268.8
MEAN DAILY MAXIMUM8147.450.358.969.377.685.188.386.580.870.660.450.068.8
HIGHEST DAILY MAXIMUM7280839396100104105102103998681105
YEAR OF OCCURRENCE195019321938199019411952197719831954194119931998JUL 1977
MEAN OF EXTREME MAXS.8169.471.280.287.891.196.097.595.993.185.577.870.184.6
NORMAL DAILY MINIMUM3025.728.136.344.654.262.767.566.459.046.537.929.946.6
MEAN DAILY MINIMUM8128.430.036.645.454.763.568.066.660.147.838.430.947.5
LOWEST DAILY MINIMUM72-12-10112331405146352110-1-12
YEAR OF OCCURRENCE194019361960198519561967196519341974196219331942JAN 1940
MEAN OF EXTREME MINS.8110.214.221.630.941.051.157.855.645.432.422.714.633.1
NORMAL DRY BULB3035.738.748.057.366.073.978.076.870.058.649.640.157.7
MEAN DRY BULB8138.040.147.857.466.274.378.276.670.559.249.540.458.2
MEAN WET BULB1734.036.741.950.559.467.371.566.063.653.744.936.852.2
MEAN DEW POINT1727.029.133.943.054.363.268.163.159.948.738.630.046.6
NORMAL NO. DAYS WITH:
MAXIMUM 90300.00.00.10.82.38.713.811.04.10.30.00.041.1
MAXIMUM 32304.31.70.10.00.00.00.00.00.00.00.01.57.6
MINIMUM 323023.019.510.82.30.10.00.00.00.02.19.419.286.4
MINIMUM 0300.30.10.00.00.00.00.00.00.00.00.00.00.4
H/CNORMAL HEATING DEG. DAYS3090873652724161000232334627723963
NORMAL COOLING DEG. DAYS30000109227040336617334001348
RHNORMAL (PERCENT)3068666361707275777774696970
HOUR 01 LST3075737273838688909086797681
HOUR 07 LST3079787876818386909089848083
HOUR 13 LST3056534945525457585752515553
HOUR 19 LST3065625753636669747775686866
SPERCENT POSSIBLE SUNSHINE4654586266656968666563595462
W/OMEAN NO. DAYS WITH:
HEAVY FOG(VISBY 1/4 MI)732.72.11.71.61.81.52.02.42.93.32.32.827.1
THUNDERSTORMS650.20.41.62.45.36.68.26.22.91.00.60.235.6
CLOUDINESSMEAN:
SUNRISE-SUNSET (OKTAS)15.65.63.2
MIDNIGHT-MIDNIGHT (OKTAS)15.6
MEAN NO. DAYS WITH:
CLEAR12.01.09.09.010.0
PARTLY CLOUDY11.05.04.08.0
CLOUDY17.04.010.08.01.0
PRMEAN STATION PRESSURE(IN)2829.9129.8929.8529.8129.8129.8129.8329.8629.8929.9229.9229.9329.87
MEAN SEA-LEVEL PRES. (IN)1730.1230.1130.0529.9930.0029.9930.0130.0430.0830.1230.1430.1430.07
WINDSMEAN SPEED (MPH)438.38.79.39.27.97.57.16.67.07.27.77.97.9
PREVAIL. DIR (TENS OF DEGS)2601013619192019193636193619
MAXIMUM 2-MINUTE:
SPEED (MPH)638393746414533444037364046
DIR. (TENS OF DEGS)31232233302629360110161533
YEAR OF OCCURRENCE200019971996199919972000199919961999199619991996 APR1999
MAXIMUM 5-SECOND:
SPEED (MPH)648494956605544595346464860
DIR. (TENS OF DEGS)31262225282729320810161628
YEAR OF OCCURRENCE200019971996199819962000199920001996199619991996MAY 1996
PRECIPITATIONNORMAL (IN)303.243.163.612.963.843.625.034.403.343.533.173.2643.16
MAXIMUM MONTHLY (IN)647.975.978.657.318.879.2418.8714.1016.609.397.647.0718.87
YEAR OF OCCURRENCE197819791984198719721938194519551999197119591973 JUL1945
MINIMUM MONTHLY (IN)640.640.480.940.640.870.380.510.520.260.010.170.400.01
YEAR OF OCCURRENCE198119781966196319651980198319431978200020011980OCT 2000
MAXIMUM IN 24 HOURS (IN)643.312.673.432.973.084.615.738.796.526.504.073.168.79
YEAR OF OCCURRENCE196219791992198719811963196919551999196119561958AUG 1955
NORMAL NO. DAYS WITH:
PRECIPITATION 0.013010.49.410.29.010.79.610.49.57.67.08.09.1110.9
PRECIPITATION 1.00300.80.70.80.61.00.91.41.31.01.20.80.711.2
SNOWFALLNORMAL (IN)305.85.52.40.10.00.00.00.00.0T0.32.216.3
MAXIMUM MONTHLY (IN)6228.521.419.72.0T0.00.00.00.0T7.312.528.5
YEAR OF OCCURRENCE19401983196019401994197919531958JAN 1940
MAXIMUM IN 24 HOURS (IN)6221.616.812.12.0T0.00.00.00.0T7.37.521.6
YEAR OF OCCURRENCE19401983196219401994197919531966JAN 1940
MAXIMUM SNOW DEPTH (IN)7718201310000006920
YEAR OF OCCURRENCE192219221980196419381958FEB 1922
NORMAL NO. DAYS WITH:
SNOWFALL 1.0301.51.40.60.*0.00.00.00.00.00.00.10.74.3
PRECIPITATION (inches) 2001 RICHMOND, VA (RIC)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
19721.435.152.113.358.878.825.803.843.357.895.822.9159.34
19732.663.113.444.583.562.453.644.341.822.561.277.0740.50
19743.212.543.791.583.021.802.256.844.830.391.234.2235.70
19755.712.968.042.782.594.0012.292.3110.983.102.044.5161.31
19763.391.352.141.083.762.852.631.354.786.991.882.5634.76
19772.221.342.672.333.991.254.206.152.167.884.325.5744.08
19787.970.485.674.313.925.264.245.930.261.214.573.8047.62
19796.165.972.593.973.802.424.367.089.763.875.501.6457.12
19806.051.015.494.284.680.385.182.152.376.962.180.4041.13
19810.642.761.522.966.623.694.012.892.702.360.685.0435.87
19822.764.443.742.973.483.979.214.392.552.902.703.3746.48
19831.593.956.045.212.505.460.510.973.054.025.634.5043.43
19843.983.978.655.924.522.013.554.581.862.143.341.5246.04
19853.543.201.800.652.364.015.3110.584.975.096.990.5849.08
19862.692.671.161.163.151.307.016.750.632.432.465.1536.56
19875.532.571.657.312.946.291.201.114.431.253.132.8640.27
19882.533.081.982.554.812.257.502.951.742.744.340.7937.26
19891.884.345.004.275.025.854.004.895.333.543.002.6249.74
19902.842.382.542.816.850.976.745.761.923.901.703.5241.93
19913.621.095.870.870.916.243.473.322.692.500.674.5335.78
19921.572.895.872.214.952.285.686.402.351.942.622.7941.55
19934.482.887.243.234.661.751.913.892.972.233.243.7742.25
19943.104.387.922.702.491.737.462.543.992.563.990.9543.81
19953.151.143.001.984.331.852.892.593.825.112.871.7134.44
19964.652.972.712.883.184.356.514.406.877.183.524.9154.13
19971.933.712.963.941.362.214.851.410.823.255.332.3634.13
19986.855.766.724.323.724.412.371.893.940.471.305.0046.75
19994.701.474.042.602.756.292.772.0016.602.251.011.7248.20
20003.961.603.674.783.036.074.058.283.600.011.722.3843.15
20012.062.553.772.142.036.532.735.082.140.650.171.6731.52
POR=64 YRS3.222.993.752.993.663.715.184.623.713.213.033.1043.17
AVERAGE TEMPERATURE (F) 2001 RICHMOND, VA (RIC)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
197240.737.647.256.264.670.177.175.270.155.847.945.957.4
197337.638.552.657.965.176.077.477.572.360.651.340.859.0
197445.840.150.459.965.870.676.975.767.455.448.541.758.2
197540.741.445.352.967.773.676.078.869.362.553.640.058.5
197635.148.552.660.565.274.677.375.768.754.442.736.757.7
197725.340.553.761.168.273.081.479.874.257.352.339.558.9
197833.430.344.557.365.574.777.580.172.958.352.542.557.5
197936.428.651.158.467.170.876.977.871.058.353.342.357.7
198038.836.047.461.168.372.880.080.774.756.946.238.658.5
198131.242.244.660.664.177.979.675.169.456.449.138.057.4
198231.641.749.155.970.473.478.675.069.859.251.946.158.6
198337.839.150.456.166.175.679.477.768.858.149.036.257.9
198432.644.543.655.865.477.776.077.067.566.146.647.758.4
198532.640.249.762.068.074.379.077.570.862.656.637.859.3
198636.239.350.059.266.976.180.974.270.861.849.140.958.8
198734.737.047.154.367.375.881.378.572.352.951.343.058.0
198832.339.147.956.065.872.879.979.868.453.650.639.257.1
198942.339.647.955.864.176.177.775.370.860.249.331.357.5
199046.348.052.157.965.875.079.976.369.563.152.646.361.1
199140.244.050.860.272.175.380.778.671.659.949.644.360.6
199240.742.747.257.861.770.879.573.770.356.350.640.957.7
199341.437.845.955.967.775.082.578.572.558.650.939.058.8
199433.440.248.963.263.278.081.175.469.257.652.645.659.0
199540.738.750.258.165.874.180.878.969.161.144.235.658.1
199634.137.843.257.964.875.176.474.370.158.943.243.856.6
199737.743.749.653.662.971.477.875.870.358.946.539.957.3
199843.244.248.558.067.474.078.378.374.259.749.544.260.0
199942.042.245.257.765.572.379.677.968.557.252.942.458.6
200036.343.452.056.468.075.474.774.967.559.746.133.057.3
200137.142.345.258.265.275.074.978.267.859.154.646.058.6
POR=72 YRS37.639.847.457.266.274.278.176.470.258.849.240.157.9

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 RICHMOND, VA (RIC)
YEARJULAUGSEPOCTNOVDECJANFEBMARAPRMAYJUNTOTAL
1972-7300172855135888437353942477903701
1973-740051634147445896914552047553345
1974-7500623105137157466546043684414017
1975-76002712135677091748038622778113373
1976-77011533266086912276803661764274375
1977-780042594017849749646272358854341
1978-79001621436669487610114392184443882
1979-800082423536988068355411354723667
1980-810014267557813104263362617110704230
1981-8201292734738341029645486280614057
1982-8306102133995858367184452826923565
1983-8401862364758879945896572829334303
1984-850073575465319976924841773553597
1985-8600311142578388867134651877833572
1986-87016241724767419317775503175704061
1987-88005370409677100874652727979324132
1988-89002736142579469670954629310803959
1989-90033818146810365744724362585033519
1990-9100331463655747625824431932713126
1991-920025190458637749640545261142103657
1992-9300372754277397247575852802403848
1993-94002621343679997368749713012003881
1994-9500112323655957507314532367213446
1995-96002816662090595278266924712284499
1996-970010193652654840589472337117453909
1997-9800192475477716675755362325073651
1998-9900101734576527106316062376073543
1999-0000292493626938826204042574523543
2000-0100611905619838586316052446704200
2001-0057213312582
COOLING DEGREE DAYS (base 65 F) 2001 RICHMOND, VA (RIC)
YEARJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECANNUAL
197200730521803813261789801171
19730013429133839139523132921544
1974001058106180377340141212601259
197500016135267348433165511801433
1976089999130738933713312001385
1977002266148258513467289242701814
19780001211230239347526315011573
197900163011718837440419542901375
19800012515724347249431323101729
1981001458939545831916916001492
198200013181259428323157431371424
19830002310832545240520727001547
198400010114392346381154100021499
1985042094139290441392213511001654
19860081914234449830820579601609
198700021363295134272270301637
19880031610826946646513712001476
19890324278834140333121842401481
19900143518131247035617796021589
199100105325431649442822740301825
1992000514819245727520212301240
199300014112307547426261201801705
199400580703965073321429221545
19951003510528149543715752301566
19960004012331536029317312001316
199700425924440634118265001303
1998203226131282420418292150121630
1999100248223146040914013201362
2000005614332030531314133001266
2001000457930731441414938701353
SNOWFALL (inches) 2001 RICHMOND, VA (RIC)
YEARJULAUGSEPOCTNOVDECJANFEBMARAPRMAYJUNTOTAL
1972-730.00.00.0T0.60.04.30.41.40.00.00.06.7
1973-740.00.00.00.00.09.9T5.0T0.00.00.014.9
1974-750.00.00.00.00.0T2.72.90.40.00.00.06.0
1975-760.00.00.00.00.0T0.2T1.00.00.00.01.2
1976-770.00.00.00.01.01.711.1T0.00.00.00.013.8
1977-780.00.00.00.0TT1.35.15.00.00.00.011.4
1978-790.00.00.00.00.00.00.719.5T0.00.00.020.2
1979-800.00.00.0T0.0T16.67.015.00.00.00.038.6
1980-810.00.00.00.00.00.20.60.00.20.00.00.01.0
1981-820.00.00.00.0T1.98.310.8T0.20.00.021.2
1982-830.00.00.00.00.07.90.121.40.0T0.00.029.4
1983-840.00.00.00.00.1T1.12.80.30.00.00.04.3
1984-850.00.00.00.00.0T8.3TT0.00.00.08.3
1985-860.00.00.00.00.01.33.34.4TT0.00.09.0
1986-870.00.00.00.00.00.015.85.30.7T0.00.021.8
1987-880.00.00.00.04.5T8.1TTT0.00.012.6
1988-890.00.00.00.00.01.8T13.6TTT0.015.4
1989-900.00.00.00.01.19.90.0TT0.20.00.011.2
1990-910.00.00.00.00.0TT1.9T0.00.00.01.9
1991-920.00.00.00.00.1T0.00.8TT0.00.00.9
1992-930.00.00.00.00.00.00.55.33.5T0.00.09.3
1993-940.00.00.00.00.05.12.21.70.70.0T0.09.7
1994-950.00.00.00.00.0T3.1T0.80.00.00.03.9
1995-960.00.00.00.0T12.3
1996-97T1.00.71.0TT0.00.0
1997-980.00.00.00.0
1998-99
1999-0015.20.2
2000-010.32.50.50.00.00.0
2001-0.00.00.00.00.00.0
POR=60 YRS0.00.00.0T0.42.04.63.92.40.1T0.013.4

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