2001 LAS VEGAS, NEVADA (LAS)



Las Vegas is situated near the center of a broad desert valley, which is almost surrounded by mountains ranging from 2,000 to l0,000 feet higher than the floor of the valley. This Vegas Valley, comprising about 600 square miles, runs from northwest to southeast, and slopes gradually upward on each side toward the surrounding mountains. Weather observations are taken at McCarran Airport, 7 miles south of downtown Las Vegas, and about 5 miles southwest and 300 feet higher than the lower portions of the valley. Since mountains encircle the valley, drainage winds are usually downslope toward the center, or lowest portion of the valley. This condition also affects minimum temperatures, which in lower portions of the valley can be from 15 to 25 degrees colder than recorded at the airport on clear, calm nights.

The four seasons are well defined. Summers display desert conditions, with maximum temperatures usually in the 100 degree range. The proximity of the mountains contributes to the relatively cool summer nights, with the majority of minimum temperatures in the mid 70s. During about 2 weeks almost every summer warm, moist air predominates in this area, and causes scattered thunderstorms, occasionally quite severe, together with higher than average humidity. Soil erosion, especially near the mountains and foothills surrounding the valley, is evidence of the intensity of some of the thunderstorm activity. Winters, on the whole, are mild and pleasant. Daytime temperatures average near 60 degrees with mostly clear skies. The spring and fall seasons are generally considered most ideal, although rather sharp temperature changes can occur during these months. There are very few days during the spring and fall months when outdoor activities are affected in any degree by the weather.

The Sierra Nevada Mountains of California and the Spring Mountains immediately west of the Vegas Valley, the latter rising to elevations over 10,000 feet above the valley floor, act as effective barriers to moisture moving eastward from the Pacific Ocean. It is mainly these barriers that result in a minimum of dark overcast and rainy days. Rainy days average less than one in June to three per month in the winter months. Snow rarely falls in this valley and it usually melts as it falls, or shortly thereafter. Notable exceptions have occurred.

Strong winds, associated with major storms, usually reach this valley from the southwest or through the pass from the northwest. Winds over 50 mph are infrequent but, when they do occur, are probably the most provoking of the elements experienced in the Vegas Valley, because of the blowing dust and sand associated with them.

Based on the 1951–1980 period, the average first occurrence of 32 degrees Fahrenheit in the fall is November 21 and the average last occurrence in the spring is March 7.

NORMALS, MEANS, AND EXTREMES

LAS VEGAS, NV (LAS)

LATITUDE:    LONGITUDE:     ELEVATION (FT):    TIME ZONE:    WBAN: 23169

36 04′ 44″ N  115 09′ 19″ W  GRND: 2127  BARO: 2091  PACIFIC (UTC + 8)

2001 Las Vegas, Nevada (LAS)

ELEMENT POR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC YEAR
TEMPERATURE F NORMAL DAILY MAXIMUM 30 57.3 63.3 68.8 77.5 87.8 100.3 105.9 103.2 94.7 82.1 67.4 57.5 80.5
MEAN DAILY MAXIMUM 53 56.4 62.4 69.2 78.1 87.7 98.4 104.0 102.0 94.3 81.2 66.2 57.1 79.7
HIGHEST DAILY MAXIMUM 53 77 87 91 99 109 115 116 116 113 103 87 77 116
YEAR OF OCCURRENCE 1975 1986 1966 2000 1951 1994 1998 1979 1950 1978 1988 1980 JUL 1998
MEAN OF EXTREME MAXS. 53 67.9 74.5 82.7 92.2 100.9 110.0 112.2 110.0 104.8 94.3 79.2 68.1 91.4
NORMAL DAILY MINIMUM 30 33.6 38.8 43.8 50.7 60.2 69.4 76.2 74.2 66.2 54.3 42.6 33.9 53.7
MEAN DAILY MINIMUM 53 34.3 38.9 44.1 51.5 60.7 69.9 76.4 74.9 66.6 54.3 42.0 34.5 54.0
LOWEST DAILY MINIMUM 53 8 16 23 31 40 48 60 56 46 26 21 11 8
YEAR OF OCCURRENCE 1963 1989 1971 1975 1964 1993 1987 1968 1965 1971 1952 1990 JAN 1963
MEAN OF EXTREME MINS. 53 23.3 27.5 32.5 39.6 47.6 56.7 66.7 65.9 55.4 42.2 30.1 24.2 42.6
NORMAL DRY BULB 30 45.5 51.1 56.3 64.1 74.0 84.9 91.1 88.7 80.5 68.3 55.0 45.7 67.1
MEAN DRY BULB 53 45.4 50.7 56.6 64.6 74.2 84.1 90.3 88.5 80.4 67.9 54.1 45.7 66.9
MEAN WET BULB 18 38.2 41.5 45.5 48.9 54.3 58.8 63.8 60.6 58.6 48.0 42.4 34.7 49.6
MEAN DEW POINT 18 25.2 27.3 28.3 27.7 32.3 35.0 43.6 43.0 39.3 29.8 26.6 21.1 31.6
NORMAL NO. DAYS WITH:
MAXIMUM 90 30 0.0 0.0 * 3.3 15.3 25.8 30.5 29.9 21.8 5.6 0.0 0.0 132.2
MAXIMUM 32 30 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 * 0.1
MINIMUM 32 30 13.0 4.7 1.3 0.1 0.0 0.0 0.0 0.0 0.0 0.1 2.2 11.4 32.8
MINIMUM 0 30 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
H/C NORMAL HEATING DEG. DAYS 30 605 389 292 143 14 0 0 0 0 62 304 598 2407
NORMAL COOLING DEG. DAYS 30 0 0 22 116 293 597 809 735 465 164 0 0 3201
RH NORMAL (PERCENT) 30 45 40 33 25 21 16 21 26 25 29 37 45 30
HOUR 04 LST 30 55 50 44 35 31 24 29 35 34 38 46 54 40
HOUR 10 LST 30 41 36 29 22 19 15 19 24 22 25 33 40 27
HOUR 16 LST 30 30 26 21 16 13 10 15 17 17 19 26 32 20
HOUR 22 LST 30 49 42 35 26 22 17 22 26 26 31 40 49 32
S PERCENT POSSIBLE SUNSHINE 47 77 81 83 87 88 93 88 88 91 87 81 78 85
W/O MEAN NO. DAYS WITH:
HEAVY FOG(VISBY 1/4 MI) 54 0.3 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.7
THUNDERSTORMS 54 0.0 0.2 0.4 0.5 1.0 1.0 3.8 3.8 1.5 0.5 0.2 0.0 12.9
CLOUDINESS MEAN:
SUNRISE-SUNSET (OKTAS) 1 1.6 0.8 0.0
MIDNIGHT-MIDNIGHT (OKTAS) 1 0.8
MEAN NO. DAYS WITH:
CLEAR 1 4.0 1.0 9.0 27.0 16.0
PARTLY CLOUDY 1 2.0 3.0 6.0 1.0
CLOUDY 1 1.0 3.0 1.0 1.0
PR MEAN STATION PRESSURE(IN) 29 27.80 27.79 27.70 27.60 27.60 27.60 27.60 27.60 27.60 27.70 27.80 27.81 27.68
MEAN SEA LEVEL PRES. (IN) 18 30.13 30.04 29.94 29.87 29.79 29.97 29.80 29.83 29.85 29.95 30.06 30.15 29.95
WINDS MEAN SPEED (MPH) 37 7.4 8.6 10.3 11.0 11.4 11.4 10.4 9.8 9.0 8.1 7.7 7.0 9.3
PREVAIL. DIR (TENS OF DEGS) 22 25 25 24 22 22 20 18 18 24 24 24 25 24
MAXIMUM 2-MINUTE:
SPEED (MPH) 6 45 46 46 44 56 47 45 43 41 46 40 48 56
DIR. (TENS OF DEGS) 23 22 33 21 22 33 03 32 16 33 24 34 22
YEAR OF OCCURRENCE 1996 2001 2001 1999 2000 1998 1998 1998 1998 1996 2001 2000 MAY 2000
MAXIMUM 5-SECOND:
SPEED (MPH) 6 52 54 56 51 64 54 54 61 49 52 49 56 64
DIR. (TENS OF DEGS) 24 20 34 34 26 33 04 16 23 33 24 33 26
YEAR OF OCCURRENCE 1999 2001 2000 1997 2000 1998 1998 1998 1998 1996 2001 1999 MAY 2000
PRECIPITATION NORMAL (IN) 30 0.48 0.48 0.42 0.21 0.28 0.12 0.35 0.49 0.28 0.21 0.43 0.38 4.13
MAXIMUM MONTHLY (IN) 53 3.00 2.89 4.80 2.44 0.96 0.97 2.48 2.59 2.06 1.22 2.22 1.71 4.80
YEAR OF OCCURRENCE 1995 1998 1992 1965 1969 1990 1984 1957 1997 1992 1965 1992 MAR 1992
MINIMUM MONTHLY (IN) 53 T 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
YEAR OF OCCURRENCE 1984 1977 1972 1962 1970 1982 1981 1980 1971 1979 1980 1981 JUN 1982
MAXIMUM IN 24 HOURS (IN) 53 1.09 1.30 1.27 0.97 0.83 0.97 1.36 2.59 1.07 1.09 1.78 0.95 2.59
YEAR OF OCCURRENCE 1990 1993 1992 1965 1987 1990 1984 1957 1963 1992 1960 1977 AUG 1957
NORMAL NO. DAYS WITH:
PRECIPITATION 0.01 30 2.9 2.8 3.3 1.9 1.5 0.8 2.4 3.1 1.9 1.8 2.1 2.6 27.1
PRECIPITATION 1.00 30 0.0 * 0.0 0.0 0.0 0.0 0.1 0.1 * 0.0 0.1 0.0 0.3
SNOWFALL NORMAL (IN) 30 0.8 0.1 0.* 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 1.1
MAXIMUM MONTHLY (IN) 48 16.7 1.4 0.1 T 0.0 0.0 0.0 T 0.0 T 4.0 2.0 16.7
YEAR OF OCCURRENCE 1949 1990 1976 1970 1989 1956 1964 1967 JAN 1949
MAXIMUM IN 24 HOURS (IN) 48 9.0 6.9 0.1 T 0.0 0.0 0.0 T 0.0 T 4.0 2.0 9.0
YEAR OF OCCURRENCE 1974 1979 1976 1970 1989 1956 1964 1967 JAN 1974
MAXIMUM SNOW DEPTH (IN) 47 8 6 0 0 0 0 0 0 0 0 3 2 8
YEAR OF OCCURRENCE 1974 1979 1964 1967 JAN 1974
NORMAL NO. DAYS WITH:
SNOWFALL 1.0 30 0.2 0.* 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.* 0.3

2001 Las Vegas, Nevada (LAS)

PRECIPITATION (inches) 2001 LAS VEGAS, NV (LAS)
YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL
1972 0.00 T 0.00 0.07 0.46 0.32 0.13 0.84 0.63 1.12 1.09 0.19 4.85
1973 0.49 1.64 1.83 0.35 0.09 0.03 T 0.08 T 0.02 0.14 0.01 4.68
1974 2.00 0.11 0.16 T T 0.00 0.58 0.08 0.16 0.61 0.23 0.59 4.52
1975 0.01 0.05 1.07 0.42 0.35 T 0.26 0.06 1.17 0.03 T 0.05 3.47
1976 0.00 2.49 0.02 0.13 0.34 0.00 1.95 0.00 1.09 0.70 0.02 0.03 6.77
1977 0.21 0.00 0.28 0.01 0.72 0.05 T 1.38 0.19 0.06 0.01 1.06 3.97
1978 1.00 1.51 1.13 0.36 0.54 0.00 0.19 0.53 0.03 0.62 0.59 1.15 7.65
1979 2.18 0.07 0.96 0.06 0.35 0.00 0.78 2.12 T 0.00 0.03 0.24 6.79
1980 1.45 2.25 0.94 0.18 0.15 T 0.43 0.00 0.18 0.04 0.00 0.01 5.63
1981 0.09 0.20 1.44 0.02 0.50 T 0.00 0.20 0.25 0.15 0.29 0.00 3.14
1982 0.09 1.10 0.29 0.01 0.31 0.00 0.05 0.71 0.07 0.04 0.60 0.72 3.99
1983 0.43 0.32 0.90 0.45 0.16 T 0.06 1.25 0.50 0.26 0.10 0.43 4.86
1984 T 0.03 T 0.04 0.00 0.22 2.48 0.99 0.47 T 0.94 1.68 6.85
1985 0.19 0.02 0.06 0.31 T 0.02 0.13 0.00 0.08 0.07 0.37 0.02 1.27
1986 0.23 0.15 0.32 0.10 0.28 T 0.13 0.04 0.05 0.07 0.81 0.47 2.65
1987 1.13 0.45 0.49 0.17 0.90 0.13 0.13 0.01 T 0.49 1.80 0.89 6.59
1988 0.65 0.26 0.00 0.76 T 0.04 0.04 0.46 T 0.00 T 0.08 2.29
1989 0.51 0.06 0.05 T 0.64 T 0.05 0.80 T T 0.00 T 2.11
1990 1.18 0.37 T 0.18 T 0.97 0.59 T 0.19 0.17 0.10 T 3.75
1991 0.21 0.54 1.01 T 0.05 0.19 0.54 0.78 0.06 0.06 0.38 0.24 4.06
1992 0.45 1.30 4.80 0.02 0.05 0.09 0.03 0.21 0.00 1.22 0.00 1.71 9.88
1993 1.63 2.52 0.14 0.01 0.01 0.08 0.00 0.26 0.00 0.02 0.17 0.21 5.05
1994 0.04 0.48 0.13 T 0.01 0.00 0.11 0.08 0.35 T 0.28 1.08 2.56
1995 3.00 0.03 0.39 0.03 0.16 0.02 T 0.05 T T 0.00 0.01 3.69
1996 0.13 0.14 0.10 0.00 0.13 T 1.18 T 0.00 0.11 0.79 0.18 2.76
1997 0.30 T 0.00 0.04 T T 0.60 0.33 2.06 T 0.23 0.07 3.63
1998 0.17 2.89 1.03 0.14 0.13 0.03 0.46 0.23 1.29 0.22 0.33 0.43 7.35
1999 T 0.08 T 0.73 T 0.14 2.18 0.25 0.35 T 0.00 T 3.73
2000 T 1.59 0.21 T T T T 0.71 0.00 0.92 T 0.04 3.47
2001 0.87 2.21 0.16 0.04 0.02 T 0.39 0.05 T 0.00 0.09 0.11 3.94
POR= 65 YRS 0.54 0.54 0.49 0.22 0.18 0.08 0.44 0.40 0.35 0.22 0.31 0.38 4.15

2001 Las Vegas, Nevada (LAS)

AVERAGE TEMPERATURE (F) 2001 LAS VEGAS, NV (LAS)
YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL
1972 42.3 52.0 63.7 65.1 74.5 84.7 93.1 86.5 78.0 63.5 49.7 41.3 66.2
1973 40.9 49.6 50.7 62.2 76.7 85.2 91.7 87.6 78.9 67.7 53.4 46.2 65.9
1974 41.0 48.9 59.5 63.4 77.0 89.1 88.8 87.7 83.4 69.3 54.8 44.4 67.3
1975 45.3 48.8 53.9 56.6 72.5 83.8 90.3 87.5 81.7 66.1 53.0 48.2 65.6
1976 46.9 53.2 53.4 62.6 77.8 81.5 86.9 85.5 78.7 66.5 58.0 46.4 66.5
1977 45.7 54.2 52.6 68.6 67.7 88.0 92.4 90.1 80.6 71.4 57.2 51.9 68.4
1978 47.9 52.1 59.9 63.1 73.1 87.1 91.9 89.0 79.0 73.5 54.2 42.9 67.8
1979 41.1 48.4 56.0 66.1 75.4 85.5 91.1 85.9 85.3 70.7 51.6 47.2 67.0
1980 49.5 53.2 54.2 63.5 69.0 83.9 92.0 90.2 81.4 68.9 56.8 52.7 67.9
1981 51.1 52.5 56.4 70.6 74.3 88.8 92.7 90.0 82.5 64.4 58.0 48.8 69.2
1982 45.6 50.5 55.1 63.8 73.6 81.5 88.1 87.3 77.9 63.0 50.5 44.5 65.1
1983 46.6 51.7 56.4 58.5 72.8 82.8 88.5 83.8 82.5 67.8 55.3 47.9 66.2
1984 47.1 50.1 57.9 63.1 80.7 83.5 88.2 85.4 81.7 63.0 52.7 44.0 66.5
1985 44.4 47.4 54.9 68.2 76.9 87.4 92.0 89.9 75.4 67.3 51.7 48.3 67.0
1986 51.7 55.8 63.0 66.2 76.6 87.8 87.6 91.2 75.4 65.0 55.8 46.0 68.5
1987 44.7 51.4 54.6 68.4 74.5 86.3 86.9 88.2 81.2 71.0 53.4 42.5 66.9
1988 45.1 52.4 58.1 64.2 73.4 85.3 92.6 86.9 79.1 74.9 56.0 46.0 67.8
1989 43.9 50.0 63.4 72.7 75.7 85.3 93.4 86.9 80.0 67.2 57.3 48.0 68.7
1990 45.2 48.8 60.5 68.8 74.5 85.9 90.8 87.8 82.0 69.2 55.1 40.2 67.4
1991 45.5 55.9 52.7 64.2 69.9 82.1 90.2 87.8 81.9 72.2 55.2 47.0 67.1
1992 45.9 54.1 56.8 70.5 77.7 83.2 88.7 90.5 83.7 70.9 52.7 43.6 68.2
1993 45.7 50.1 60.9 67.5 77.0 82.5 89.4 88.5 81.3 69.1 51.5 46.3 67.5
1994 49.3 48.5 62.7 67.6 76.6 90.3 93.3 92.9 83.1 67.2 49.4 47.5 69.0
1995 47.5 58.7 57.9 64.8 71.0 80.9 92.4 93.1 83.7 69.4 59.8 48.9 69.0
1996 48.5 54.8 59.8 68.3 77.3 87.0 93.2 91.9 80.4 66.8 56.5 47.9 69.4
1997 48.3 51.7 62.7 65.4 81.6 84.3 88.2 90.7 81.3 67.3 56.2 45.9 68.6
1998 48.7 49.4 56.6 61.1 70.0 80.0 91.7 92.0 80.0 66.6 54.8 47.8 66.6
1999 50.5 52.7 60.6 60.9 75.3 85.2 88.2 88.0 81.6 71.6 58.8 48.7 68.5
2000 51.4 53.6 58.6 71.2 80.8 88.7 92.3 90.5 81.7 67.3 50.2 49.5 69.7
2001 46.4 49.8 60.6 65.0 82.2 87.9 90.3 91.9 85.1 72.1 58.6 45.4 69.6
POR= 65 YRS 45.2 50.1 56.3 64.5 74.1 83.6 89.9 88.2 80.1 67.6 53.7 45.9 66.6

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.

2001 Las Vegas, Nevada (LAS)

HEATING DEGREE DAYS (base 65 F) 2001 LAS VEGAS, NV (LAS)
YEAR JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN TOTAL
1972-73 0 0 0 108 453 727 744 428 437 132 12 0 3041
1973-74 0 0 0 42 349 576 738 443 188 82 13 0 2431
1974-75 0 0 0 55 300 634 607 446 340 249 37 0 2668
1975-76 0 0 0 73 354 516 553 339 357 124 1 0 2317
1976-77 0 0 0 39 212 569 593 297 374 45 56 0 2185
1977-78 0 0 0 3 226 399 522 356 168 91 16 0 1781
1978-79 0 0 1 2 324 676 737 458 270 66 18 0 2552
1979-80 0 0 0 44 395 546 474 335 328 108 32 0 2262
1980-81 0 0 0 82 255 374 426 344 263 29 2 0 1775
1981-82 0 0 0 74 214 497 594 398 301 98 9 0 2185
1982-83 0 0 10 84 429 631 564 364 263 198 21 0 2564
1983-84 0 0 0 3 297 524 548 424 216 111 0 0 2123
1984-85 0 0 0 127 363 641 629 487 308 41 0 0 2596
1985-86 0 0 1 31 393 512 404 270 125 57 11 0 1804
1986-87 0 0 14 53 268 586 622 375 316 40 1 0 2275
1987-88 0 0 0 18 342 689 612 357 225 83 33 0 2359
1988-89 0 0 0 0 291 581 647 425 118 23 16 0 2101
1989-90 0 0 0 70 224 519 606 449 172 12 0 0 2052
1990-91 0 0 0 23 290 761 597 247 376 57 25 2 2378
1991-92 0 0 0 77 297 552 584 308 248 7 0 0 2073
1992-93 0 0 0 16 364 655 591 410 143 32 3 8 2222
1993-94 0 0 0 33 398 573 480 455 93 60 1 0 2093
1994-95 0 0 0 35 465 537 537 170 230 90 18 6 2088
1995-96 0 0 0 22 151 490 504 287 169 22 11 0 1656
1996-97 0 0 0 138 249 524 512 368 115 117 0 0 2023
1997-98 0 0 0 57 259 583 500 426 270 166 23 0 2284
1998-99 0 0 0 39 296 525 444 337 143 188 5 6 1983
1999-00 0 0 0 11 184 499 412 325 195 16 3 0 1645
2000-01 0 0 0 80 436 474 570 421 175 114 2 0 2272
2001- 0 0 0 0 204 602

2001 Las Vegas, Nevada (LAS)

COOLING DEGREE DAYS (base 65 F) 2001 LAS VEGAS, NV (LAS)
YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL
1972 0 2 66 80 308 597 876 675 398 69 0 0 3071
1973 0 0 0 54 382 612 833 708 424 134 8 0 3155
1974 0 0 24 43 394 731 744 713 559 195 0 0 3403
1975 0 0 2 2 276 570 792 704 508 117 2 0 2973
1976 0 0 2 57 404 500 687 641 419 93 6 0 2809
1977 0 0 0 161 149 694 858 781 476 210 3 0 3332
1978 0 0 17 40 277 672 841 752 425 268 8 0 3300
1979 0 0 0 104 346 625 813 656 614 229 0 0 3387
1980 0 0 0 68 160 575 842 788 498 211 15 0 3157
1981 0 0 5 205 296 721 866 781 531 64 12 0 3481
1982 0 0 2 70 281 501 721 699 404 30 0 0 2708
1983 0 0 2 9 269 541 735 589 534 94 10 0 2783
1984 0 0 3 61 496 563 724 641 508 74 1 0 3071
1985 0 0 0 143 377 678 844 778 319 110 2 0 3251
1986 0 20 69 98 379 693 707 821 332 59 0 0 3178
1987 0 0 0 148 302 645 685 729 495 211 0 0 3215
1988 0 0 16 64 300 615 864 685 434 312 31 0 3321
1989 0 11 74 259 351 614 887 687 456 143 0 0 3482
1990 0 0 42 134 302 634 810 713 516 163 0 0 3314
1991 0 0 0 42 187 524 788 714 515 307 12 0 3089
1992 0 0 0 180 402 552 742 798 571 206 3 0 3454
1993 0 0 21 114 381 537 765 737 494 166 0 0 3215
1994 0 0 31 145 369 768 883 870 551 108 0 0 3725
1995 0 0 13 91 211 490 856 880 570 168 2 0 3281
1996 0 3 16 129 402 665 883 841 471 201 0 0 3611
1997 0 0 48 136 522 584 727 805 494 137 4 0 3457
1998 0 0 18 55 186 457 834 842 456 95 0 0 2943
1999 0 0 13 74 333 620 726 719 508 221 3 0 3217
2000 0 0 3 208 498 719 851 799 509 158 0 0 3745
2001 0 0 47 122 541 692 792 843 609 231 17 0 3894

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.




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