Record envelope, standing records and threshold days for Boulder City (USC00261071), Nevada, United States, with 74 years of record.
Key Facts for Boulder City
Boulder City (USC00261071) is a weather station in Nevada, United States at 35.98 latitude and -114.85 longitude, 762 m (2,500 ft) above sea level.
The station reports from 1931 to 2004, 74 years of record.
1,464 records set at Boulder City still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Boulder City set a daily record precipitation of 5.1 mm (0.20 in) on 16 July 2004.
About the Station
Location: Nevada, United States, 35.98 latitude, -114.85 longitude.
Elevation: 762 m (2,500 ft).
Period of record: 1931 to 2004, 74 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
0 days at or beyond a record
Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Boulder City. The lines show the 2026 daily maximum and minimum. 0 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Boulder City, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
26.7 C (80.1 F)
-11.7 C (10.9 F)
n/a
n/a
Feb
30.0 C (86.0 F)
-11.1 C (12.0 F)
n/a
n/a
Mar
32.8 C (91.0 F)
-3.9 C (25.0 F)
n/a
n/a
Apr
36.1 C (97.0 F)
-0.6 C (30.9 F)
n/a
n/a
May
43.9 C (111.0 F)
2.8 C (37.0 F)
n/a
n/a
Jun
45.6 C (114.1 F)
5.0 C (41.0 F)
n/a
n/a
Jul
47.2 C (117.0 F)
14.4 C (57.9 F)
n/a
n/a
Aug
44.4 C (111.9 F)
15.0 C (59.0 F)
n/a
n/a
Sep
43.3 C (109.9 F)
6.1 C (43.0 F)
n/a
n/a
Oct
37.8 C (100.0 F)
-1.1 C (30.0 F)
n/a
n/a
Nov
32.2 C (90.0 F)
-3.9 C (25.0 F)
n/a
n/a
Dec
25.6 C (78.1 F)
-12.8 C (9.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Boulder City still stand. 1934 holds the most, with 44.
Standing records at Boulder City by the year they were set
Year set
Standing records
1931
10
1932
27
1933
43
1934
44
1935
10
1936
18
1937
41
1938
24
1939
20
1940
22
1941
19
1942
6
1943
21
1944
12
1945
17
1946
12
1947
21
1948
13
1949
40
1950
29
1951
22
1952
18
1953
20
1954
16
1955
32
1956
12
1957
22
1958
16
1959
16
1960
17
1961
15
1962
32
1963
27
1964
36
1965
26
1966
9
1967
16
1968
12
1969
8
1970
12
1971
41
1972
35
1973
11
1974
15
1975
31
1976
3
1977
9
1978
15
1979
8
1980
28
1981
16
1982
13
1983
11
1984
10
1985
27
1986
25
1987
11
1988
19
1989
31
1990
21
1991
19
1992
16
1993
8
1994
15
1995
25
1996
40
1997
18
1998
21
1999
12
2000
26
2001
17
2002
8
2003
15
2004
11
All-Time Record Progression
5 new records
5 all-time records were set at Boulder City between 15 July 1964 and 23 December 1990. Each dot is a new record.
When Boulder City set new all-time records
Date
Kind
Detail
1964-07-15
Record high maximum temperature
Record high maximum temperature 47.2 C (117.0 F)
1972-07-14
Record high minimum temperature
Record high minimum temperature 34.4 C (93.9 F)
1976-09-11
Record daily precipitation
Record daily precipitation 66.5 mm (2.6 in)
1984-08-14
Record daily precipitation
Record daily precipitation 94.5 mm (3.7 in)
1990-12-23
Record low minimum temperature
Record low minimum temperature -12.8 C (9.0 F)
Wettest Day of Each Month
Aug: 94.5 mm (3.7 in)
The wettest day on record for each calendar month at Boulder City. The most was 94.5 mm (3.7 in) on 14 August 1984.
Record daily precipitation for each month at Boulder City
Month
Record daily precipitation (mm)
Date
Jan
22.1 mm (0.9 in)
17 January 1993
Feb
41.1 mm (1.6 in)
13 February 1992
Mar
42.2 mm (1.7 in)
8 March 1952
Apr
26.7 mm (1.1 in)
1 April 1965
May
27.4 mm (1.1 in)
11 May 1958
Jun
17.8 mm (0.7 in)
27 June 1964
Jul
48.0 mm (1.9 in)
30 July 1936
Aug
94.5 mm (3.7 in)
14 August 1984
Sep
66.8 mm (2.6 in)
10 September 1984
Oct
33.0 mm (1.3 in)
24 October 1992
Nov
48.8 mm (1.9 in)
6 November 1960
Dec
28.2 mm (1.1 in)
25 December 1994
Period of Record Coverage
1931 to 2004
Complete yearUnder 90 percent of days
74 years of record at Boulder City, 1931 to 2004. 8 years have data for under 90 percent of days and are left out of rankings: 1931, 1976, 1979, 2000, 2001, 2002, 2003, 2004.
Cooler than the station meanWarmer than the station mean
One stripe for each of 62 complete years at Boulder City, 1932 to 1999. Blue stripes are years cooler than the station's own mean of 19.6 C (67.3 F); red stripes are warmer. The coolest year was 1982, at 18.1 C (64.6 F), and the warmest was 1996, at 21.6 C (70.9 F). The strongest colour marks a difference of 2.1 C (3.8 F).
Annual mean temperature at Boulder City as warming stripes, 1932 to 1999
Year
Annual mean temperature
Difference from the station mean
1932
19.1 C
-0.52 C
1933
19.1 C
-0.50 C
1934
21.3 C
+1.67 C
1935
19.3 C
-0.28 C
1936
19.9 C
+0.27 C
1937
19.5 C
-0.13 C
1938
19.2 C
-0.44 C
1939
19.4 C
-0.22 C
1940
20.2 C
+0.58 C
1941
18.3 C
-1.32 C
1942
19.6 C
-0.03 C
1943
20.0 C
+0.39 C
1944
18.7 C
-0.96 C
1945
19.1 C
-0.54 C
1946
19.4 C
-0.24 C
1947
19.9 C
+0.23 C
1948
18.7 C
-0.93 C
1949
18.6 C
-1.02 C
1950
20.1 C
+0.51 C
1951
18.7 C
-0.90 C
1952
18.8 C
-0.85 C
1954
20.0 C
+0.34 C
1955
18.6 C
-1.03 C
1956
19.7 C
+0.05 C
1957
19.2 C
-0.45 C
1958
19.9 C
+0.30 C
1959
20.1 C
+0.43 C
1960
19.7 C
+0.11 C
1961
19.6 C
-0.06 C
1962
20.2 C
+0.54 C
1963
19.9 C
+0.25 C
1964
19.2 C
-0.47 C
1965
18.8 C
-0.83 C
1966
19.8 C
+0.14 C
1967
19.6 C
-0.03 C
1968
19.8 C
+0.17 C
1969
19.9 C
+0.29 C
1970
19.6 C
-0.07 C
1971
18.8 C
-0.79 C
1972
19.9 C
+0.26 C
1973
19.0 C
-0.58 C
1974
19.2 C
-0.41 C
1978
19.1 C
-0.57 C
1980
19.3 C
-0.36 C
1981
20.2 C
+0.53 C
1982
18.1 C
-1.51 C
1983
18.9 C
-0.77 C
1984
19.7 C
+0.11 C
1985
19.9 C
+0.28 C
1986
20.5 C
+0.83 C
1987
19.7 C
+0.03 C
1988
20.4 C
+0.76 C
1989
20.9 C
+1.23 C
1990
20.0 C
+0.38 C
1991
19.7 C
+0.05 C
1992
20.0 C
+0.42 C
1993
19.7 C
+0.05 C
1995
20.6 C
+0.97 C
1996
21.6 C
+2.01 C
1997
20.9 C
+1.23 C
1998
19.5 C
-0.15 C
1999
21.1 C
+1.48 C
The annual mean temperature here has risen by 0.13 C (0.04 to 0.21) per decade over 1932 to 1999. In Fahrenheit: 0.2 F (0.1 to 0.4) per decade. The slope is a straight line fitted to 62 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Boulder City
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.13 C (0.04 to 0.21) per decade
0.2 F (0.1 to 0.4) per decade
1932 to 1999
62
Rise
Mean daily maximum
0.2 C (0.1 to 0.3) per decade
0.3 F (0.2 to 0.5) per decade
1932 to 1999
62
Rise
Mean daily minimum
0.06 C (-0.04 to 0.17) per decade
0.1 F (-0.1 to 0.3) per decade
1932 to 1999
62
Not clearly different from zero
A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.
Extremes by Year
1931 to 2004
Yearly extremes at Boulder City: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
47.2 C (117.0 F)
1964
43.3 C (109.9 F)
74
Coldest night (TNn)
-12.8 C (9.0 F)
1990
-3.3 C (26.1 F)
74
Wettest day (Rx1day)
94.5 mm (3.7 in)
1984
22.1 mm (0.9 in)
74
Wettest five days (Rx5day)
117.4 mm (4.6 in)
1984
30.0 mm (1.2 in)
74
Longest dry spell (CDD)
162 days
1985
78 days
74
Hottest day (TXx)
The hottest day of the year at Boulder City, 1931 to 2004. The record is 47.2 C (117.0 F) in 1964, marked on the chart; the median year is 43.3 C (109.9 F).
Hottest day (TXx) at Boulder City by year
Year
Hottest day (TXx)
1931
39.4 C (102.9 F)
1932
43.9 C (111.0 F)
1933
44.4 C (111.9 F)
1934
44.4 C (111.9 F)
1935
42.2 C (108.0 F)
1936
42.8 C (109.0 F)
1937
43.9 C (111.0 F)
1938
44.4 C (111.9 F)
1939
44.4 C (111.9 F)
1940
44.4 C (111.9 F)
1941
42.2 C (108.0 F)
1942
44.4 C (111.9 F)
1943
43.9 C (111.0 F)
1944
41.7 C (107.1 F)
1945
41.7 C (107.1 F)
1946
43.3 C (109.9 F)
1947
42.2 C (108.0 F)
1948
42.8 C (109.0 F)
1949
43.9 C (111.0 F)
1950
44.4 C (111.9 F)
1951
42.8 C (109.0 F)
1952
42.2 C (108.0 F)
1953
42.8 C (109.0 F)
1954
45.6 C (114.1 F)
1955
42.2 C (108.0 F)
1956
43.3 C (109.9 F)
1957
43.3 C (109.9 F)
1958
44.4 C (111.9 F)
1959
43.3 C (109.9 F)
1960
45.0 C (113.0 F)
1961
44.4 C (111.9 F)
1962
43.3 C (109.9 F)
1963
42.2 C (108.0 F)
1964
47.2 C (117.0 F)
1965
41.7 C (107.1 F)
1966
42.8 C (109.0 F)
1967
44.4 C (111.9 F)
1968
42.8 C (109.0 F)
1969
43.9 C (111.0 F)
1970
44.4 C (111.9 F)
1971
43.3 C (109.9 F)
1972
45.6 C (114.1 F)
1973
44.4 C (111.9 F)
1974
42.2 C (108.0 F)
1975
43.3 C (109.9 F)
1976
38.9 C (102.0 F)
1977
43.3 C (109.9 F)
1978
42.8 C (109.0 F)
1979
35.0 C (95.0 F)
1980
43.3 C (109.9 F)
1981
43.3 C (109.9 F)
1982
41.7 C (107.1 F)
1983
42.8 C (109.0 F)
1984
43.9 C (111.0 F)
1985
46.7 C (116.1 F)
1986
42.8 C (109.0 F)
1987
42.8 C (109.0 F)
1988
43.3 C (109.9 F)
1989
45.0 C (113.0 F)
1990
43.9 C (111.0 F)
1991
43.3 C (109.9 F)
1992
43.3 C (109.9 F)
1993
43.3 C (109.9 F)
1994
43.9 C (111.0 F)
1995
44.4 C (111.9 F)
1996
43.9 C (111.0 F)
1997
42.2 C (108.0 F)
1998
45.6 C (114.1 F)
1999
42.8 C (109.0 F)
2000
43.9 C (111.0 F)
2001
44.4 C (111.9 F)
2002
43.9 C (111.0 F)
2003
41.7 C (107.1 F)
2004
41.1 C (106.0 F)
Coldest night (TNn)
The coldest night of the year at Boulder City, 1931 to 2004. The record is -12.8 C (9.0 F) in 1990, marked on the chart; the median year is -3.3 C (26.1 F).
Coldest night (TNn) at Boulder City by year
Year
Coldest night (TNn)
1931
-3.3 C (26.1 F)
1932
-8.3 C (17.1 F)
1933
-11.1 C (12.0 F)
1934
-1.1 C (30.0 F)
1935
-3.9 C (25.0 F)
1936
-1.1 C (30.0 F)
1937
-11.7 C (10.9 F)
1938
0.0 C (32.0 F)
1939
-2.2 C (28.0 F)
1940
-2.2 C (28.0 F)
1941
-2.2 C (28.0 F)
1942
-3.3 C (26.1 F)
1943
-3.9 C (25.0 F)
1944
-0.6 C (30.9 F)
1945
-3.3 C (26.1 F)
1946
-1.7 C (28.9 F)
1947
-1.7 C (28.9 F)
1948
-3.9 C (25.0 F)
1949
-8.3 C (17.1 F)
1950
-7.2 C (19.0 F)
1951
-3.3 C (26.1 F)
1952
-4.4 C (24.1 F)
1953
-1.1 C (30.0 F)
1954
-1.7 C (28.9 F)
1955
-2.8 C (27.0 F)
1956
-3.9 C (25.0 F)
1957
-3.3 C (26.1 F)
1958
-2.2 C (28.0 F)
1959
-2.2 C (28.0 F)
1960
-3.9 C (25.0 F)
1961
-3.3 C (26.1 F)
1962
-5.6 C (21.9 F)
1963
-10.0 C (14.0 F)
1964
-6.1 C (21.0 F)
1965
-2.8 C (27.0 F)
1966
-4.4 C (24.1 F)
1967
-5.6 C (21.9 F)
1968
-5.6 C (21.9 F)
1969
-1.7 C (28.9 F)
1970
-3.9 C (25.0 F)
1971
-6.7 C (19.9 F)
1972
-5.6 C (21.9 F)
1973
-4.4 C (24.1 F)
1974
-8.9 C (16.0 F)
1975
-5.0 C (23.0 F)
1976
-0.6 C (30.9 F)
1977
-1.1 C (30.0 F)
1978
-6.1 C (21.0 F)
1979
-5.6 C (21.9 F)
1980
0.6 C (33.1 F)
1981
0.0 C (32.0 F)
1982
-5.0 C (23.0 F)
1983
-2.8 C (27.0 F)
1984
-1.7 C (28.9 F)
1985
-6.7 C (19.9 F)
1986
-2.2 C (28.0 F)
1987
-6.1 C (21.0 F)
1988
-6.7 C (19.9 F)
1989
-8.9 C (16.0 F)
1990
-12.8 C (9.0 F)
1991
-4.4 C (24.1 F)
1992
-3.9 C (25.0 F)
1993
-3.9 C (25.0 F)
1994
-2.2 C (28.0 F)
1995
1.1 C (34.0 F)
1996
-0.6 C (30.9 F)
1997
-1.1 C (30.0 F)
1998
-3.3 C (26.1 F)
1999
0.6 C (33.1 F)
2000
1.1 C (34.0 F)
2001
0.6 C (33.1 F)
2002
-1.1 C (30.0 F)
2003
-0.6 C (30.9 F)
2004
-0.6 C (30.9 F)
Wettest day (Rx1day)
The wettest day of the year at Boulder City, 1931 to 2004. The record is 94.5 mm (3.7 in) in 1984, marked on the chart; the median year is 22.1 mm (0.9 in).
Wettest day (Rx1day) at Boulder City by year
Year
Wettest day (Rx1day)
1931
23.6 mm (0.9 in)
1932
16.5 mm (0.6 in)
1933
17.3 mm (0.7 in)
1934
19.6 mm (0.8 in)
1935
24.1 mm (0.9 in)
1936
48.0 mm (1.9 in)
1937
10.9 mm (0.4 in)
1938
16.5 mm (0.6 in)
1939
27.4 mm (1.1 in)
1940
24.4 mm (1.0 in)
1941
24.1 mm (0.9 in)
1942
21.8 mm (0.9 in)
1943
21.3 mm (0.8 in)
1944
14.5 mm (0.6 in)
1945
28.2 mm (1.1 in)
1946
20.1 mm (0.8 in)
1947
22.4 mm (0.9 in)
1948
7.4 mm (0.29 in)
1949
19.6 mm (0.8 in)
1950
18.3 mm (0.7 in)
1951
28.4 mm (1.1 in)
1952
42.2 mm (1.7 in)
1953
7.6 mm (0.30 in)
1954
18.3 mm (0.7 in)
1955
18.5 mm (0.7 in)
1956
5.6 mm (0.22 in)
1957
48.8 mm (1.9 in)
1958
27.4 mm (1.1 in)
1959
23.4 mm (0.9 in)
1960
48.8 mm (1.9 in)
1961
13.7 mm (0.5 in)
1962
24.9 mm (1.0 in)
1963
19.3 mm (0.8 in)
1964
17.8 mm (0.7 in)
1965
26.7 mm (1.1 in)
1966
15.7 mm (0.6 in)
1967
22.6 mm (0.9 in)
1968
9.1 mm (0.36 in)
1969
26.7 mm (1.1 in)
1970
39.6 mm (1.6 in)
1971
22.1 mm (0.9 in)
1972
22.1 mm (0.9 in)
1973
15.7 mm (0.6 in)
1974
31.2 mm (1.2 in)
1975
20.1 mm (0.8 in)
1976
66.5 mm (2.6 in)
1977
32.3 mm (1.3 in)
1978
28.7 mm (1.1 in)
1979
14.0 mm (0.6 in)
1980
26.4 mm (1.0 in)
1981
50.8 mm (2.0 in)
1982
24.9 mm (1.0 in)
1983
15.0 mm (0.6 in)
1984
94.5 mm (3.7 in)
1985
20.3 mm (0.8 in)
1986
14.5 mm (0.6 in)
1987
23.9 mm (0.9 in)
1988
11.7 mm (0.5 in)
1989
33.0 mm (1.3 in)
1990
20.3 mm (0.8 in)
1991
25.1 mm (1.0 in)
1992
41.1 mm (1.6 in)
1993
28.7 mm (1.1 in)
1994
28.2 mm (1.1 in)
1995
25.1 mm (1.0 in)
1996
18.0 mm (0.7 in)
1997
61.5 mm (2.4 in)
1998
22.1 mm (0.9 in)
1999
13.2 mm (0.5 in)
2000
5.1 mm (0.20 in)
2001
6.9 mm (0.27 in)
2002
10.2 mm (0.4 in)
2003
25.7 mm (1.0 in)
2004
14.2 mm (0.6 in)
Wettest five days (Rx5day)
The wettest five days of the year at Boulder City, 1931 to 2004. The record is 117.4 mm (4.6 in) in 1984, marked on the chart; the median year is 30.0 mm (1.2 in).
Wettest five days (Rx5day) at Boulder City by year
Year
Wettest five days (Rx5day)
1931
26.1 mm (1.0 in)
1932
25.1 mm (1.0 in)
1933
20.1 mm (0.8 in)
1934
30.0 mm (1.2 in)
1935
42.9 mm (1.7 in)
1936
61.0 mm (2.4 in)
1937
19.0 mm (0.7 in)
1938
39.9 mm (1.6 in)
1939
36.5 mm (1.4 in)
1940
36.1 mm (1.4 in)
1941
31.3 mm (1.2 in)
1942
21.9 mm (0.9 in)
1943
44.5 mm (1.8 in)
1944
26.1 mm (1.0 in)
1945
48.6 mm (1.9 in)
1946
26.5 mm (1.0 in)
1947
45.5 mm (1.8 in)
1948
11.7 mm (0.5 in)
1949
52.4 mm (2.1 in)
1950
29.7 mm (1.2 in)
1951
28.4 mm (1.1 in)
1952
46.8 mm (1.8 in)
1953
15.7 mm (0.6 in)
1954
30.0 mm (1.2 in)
1955
24.4 mm (1.0 in)
1956
10.4 mm (0.4 in)
1957
73.2 mm (2.9 in)
1958
29.0 mm (1.1 in)
1959
46.5 mm (1.8 in)
1960
67.4 mm (2.7 in)
1961
13.7 mm (0.5 in)
1962
40.1 mm (1.6 in)
1963
21.9 mm (0.9 in)
1964
17.8 mm (0.7 in)
1965
55.4 mm (2.2 in)
1966
26.7 mm (1.1 in)
1967
26.5 mm (1.0 in)
1968
15.1 mm (0.6 in)
1969
26.7 mm (1.1 in)
1970
39.6 mm (1.6 in)
1971
32.3 mm (1.3 in)
1972
28.9 mm (1.1 in)
1973
21.8 mm (0.9 in)
1974
35.9 mm (1.4 in)
1975
20.1 mm (0.8 in)
1976
73.1 mm (2.9 in)
1977
32.3 mm (1.3 in)
1978
62.3 mm (2.5 in)
1979
30.0 mm (1.2 in)
1980
58.6 mm (2.3 in)
1981
63.2 mm (2.5 in)
1982
29.8 mm (1.2 in)
1983
25.6 mm (1.0 in)
1984
117.4 mm (4.6 in)
1985
26.2 mm (1.0 in)
1986
15.0 mm (0.6 in)
1987
53.6 mm (2.1 in)
1988
18.4 mm (0.7 in)
1989
33.0 mm (1.3 in)
1990
34.1 mm (1.3 in)
1991
42.2 mm (1.7 in)
1992
60.2 mm (2.4 in)
1993
38.5 mm (1.5 in)
1994
32.3 mm (1.3 in)
1995
30.3 mm (1.2 in)
1996
21.3 mm (0.8 in)
1997
71.9 mm (2.8 in)
1998
39.9 mm (1.6 in)
1999
17.5 mm (0.7 in)
2000
6.4 mm (0.25 in)
2001
6.9 mm (0.27 in)
2002
10.2 mm (0.4 in)
2003
27.3 mm (1.1 in)
2004
22.1 mm (0.9 in)
Longest dry spell (CDD)
The longest dry spell of the year at Boulder City, 1931 to 2004. The record is 162 days in 1985, marked on the chart; the median year is 78 days.
Longest dry spell (CDD) at Boulder City by year
Year
Longest dry spell (CDD)
1931
39 days
1932
78 days
1933
78 days
1934
56 days
1935
62 days
1936
104 days
1937
98 days
1938
77 days
1939
74 days
1940
100 days
1941
56 days
1942
82 days
1943
107 days
1944
113 days
1945
107 days
1946
59 days
1947
129 days
1948
132 days
1949
61 days
1950
125 days
1951
63 days
1952
51 days
1953
78 days
1954
56 days
1955
81 days
1956
94 days
1957
50 days
1958
77 days
1959
88 days
1960
102 days
1961
83 days
1962
97 days
1963
74 days
1964
141 days
1965
78 days
1966
52 days
1967
77 days
1968
65 days
1969
53 days
1970
120 days
1971
76 days
1972
104 days
1973
87 days
1974
127 days
1975
82 days
1976
35 days
1977
106 days
1978
88 days
1979
51 days
1980
66 days
1981
73 days
1982
65 days
1983
81 days
1984
71 days
1985
162 days
1986
74 days
1987
88 days
1988
100 days
1989
80 days
1990
73 days
1991
64 days
1992
43 days
1993
83 days
1994
51 days
1995
140 days
1996
88 days
1997
73 days
1998
41 days
1999
99 days
2000
160 days
2001
162 days
2002
66 days
2003
71 days
2004
97 days
Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.
Frost Dates and Growing Season
43 years with a frost
Across 43 years with a frost, the median last spring frost at Boulder City falls on 25 February and the median first autumn frost on 12 December, which leaves a median of 295 days between them.
Fitted over all years, the growing season changes by +2.3 days per decade at this station.
Frost dates and growing season at Boulder City
Measure
Median, all years
Earliest period
Recent period (1955 to 1997)
Recent against earliest
Fitted trend
Last spring frost
25 February
n/a
20 February
n/a
-3.3 days per decade
First autumn frost
12 December
n/a
12 December
n/a
-1.0 days per decade
Growing days
295 days
n/a
297 days
n/a
+2.3 days per decade
A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.
Rainfall Return Levels
67 years, 1932 to 2001
A day with at least 21.7 mm (0.9 in) of rain is expected about once in 2 years. A day with at least 74.6 mm (2.9 in) of rain is expected about once in 100 years.
Rainfall return levels at Boulder City: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
21.7 mm (0.9 in)
5 years
32.5 mm (1.3 in)
10 years
40.8 mm (1.6 in)
25 years
52.9 mm (2.1 in)
50 years
63.2 mm (2.5 in)
100 years
74.6 mm (2.9 in)
Longer than the 67 years of record
The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 67 years of values from 1932 to 2001.
A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.
The largest wettest-day totals in the fit: 94.5 mm (3.7 in) in 1984; 61.5 mm (2.4 in) in 1997; 50.8 mm (2.0 in) in 1981.
Station Changes
3 suspected
3 changes were suspected in the annual mean temperature of Boulder City, at 1962, 1974 and 1984. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1962 ran 0.3 C (0.6 F) higher than in the years before (likely change).
Relative to 5 neighbouring stations, the station's annual mean temperature from 1974 ran 0.7 C (1.3 F) lower than in the years before (likely change).
Relative to 5 neighbouring stations, the station's annual mean temperature from 1984 ran 0.9 C (1.5 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at Boulder City, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1962
+0.3
+0.6
likely
5
1974
-0.7
-1.3
likely
5
1984
+0.9
+1.5
likely
5
Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. How changes are found, and the largest ones.
Download the Data
Data for Boulder City standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Boulder City threshold days by year: CSV or JSON. Field meanings are on the data page.
Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-14 (14 October 2026). Records are computed by this site and are not official.