Record envelope, standing records and threshold days for Monument 2 WSW (USC00055730), Colorado, United States, with 54 years of record.
Key Facts for Monument 2 WSW
Monument 2 WSW (USC00055730) is a weather station in Colorado, United States at 39.08 latitude and -104.93 longitude, 2,239 m (7,346 ft) above sea level.
The station reports from 1911 to 1964, 54 years of record.
1,464 records set at Monument 2 WSW still stand.
Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
Monument 2 WSW set a daily record low minimum temperature of -0.6 C (30.9 F) on 1 September 1964.
About the Station
Location: Colorado, United States, 39.08 latitude, -104.93 longitude.
Elevation: 2,239 m (7,346 ft).
Period of record: 1911 to 1964, 54 years.
Eligible elements: tmax, tmin, prcp, snow.
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 Monument 2 WSW. 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 Monument 2 WSW, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
19.4 C (66.9 F)
-36.1 C (-33.0 F)
n/a
n/a
Feb
23.3 C (73.9 F)
-40.0 C (-40.0 F)
n/a
n/a
Mar
23.9 C (75.0 F)
-28.3 C (-18.9 F)
n/a
n/a
Apr
25.6 C (78.1 F)
-23.3 C (-9.9 F)
n/a
n/a
May
31.1 C (88.0 F)
-10.0 C (14.0 F)
n/a
n/a
Jun
37.8 C (100.0 F)
-6.7 C (19.9 F)
n/a
n/a
Jul
37.2 C (99.0 F)
1.1 C (34.0 F)
n/a
n/a
Aug
36.7 C (98.1 F)
1.1 C (34.0 F)
n/a
n/a
Sep
33.9 C (93.0 F)
-8.9 C (16.0 F)
n/a
n/a
Oct
31.1 C (88.0 F)
-22.8 C (-9.0 F)
n/a
n/a
Nov
23.3 C (73.9 F)
-27.2 C (-17.0 F)
n/a
n/a
Dec
21.1 C (70.0 F)
-33.9 C (-29.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Monument 2 WSW still stand. 1911 holds the most, with 49.
Standing records at Monument 2 WSW by the year they were set
Year set
Standing records
1911
49
1912
32
1913
35
1914
29
1915
39
1916
32
1917
23
1918
35
1919
20
1920
32
1921
20
1922
17
1923
20
1924
32
1925
32
1926
33
1927
36
1928
35
1929
30
1930
25
1931
20
1932
29
1933
24
1934
35
1935
15
1936
30
1937
25
1938
26
1939
28
1940
24
1941
20
1942
21
1943
28
1944
14
1945
27
1946
35
1947
28
1948
40
1949
12
1950
33
1951
35
1952
30
1953
25
1954
36
1955
23
1956
20
1957
14
1958
17
1959
27
1960
34
1961
26
1962
25
1963
26
1964
6
All-Time Record Progression
2 new records
2 all-time records were set at Monument 2 WSW between 11 January 1963 and 12 January 1963. Each dot is a new record.
When Monument 2 WSW set new all-time records
Date
Kind
Detail
1963-01-11
Record low maximum temperature
Record low maximum temperature -23.3 C (-9.9 F)
1963-01-12
Record low maximum temperature
Record low maximum temperature -23.9 C (-11.0 F)
Wettest Day of Each Month
Apr: 102.9 mm (4.1 in)
The wettest day on record for each calendar month at Monument 2 WSW. The most was 102.9 mm (4.1 in) on 15 April 1921.
Record daily precipitation for each month at Monument 2 WSW
Month
Record daily precipitation (mm)
Date
Jan
31.5 mm (1.2 in)
23 January 1921
Feb
27.7 mm (1.1 in)
14 February 1960
Mar
38.4 mm (1.5 in)
20 March 1959
Apr
102.9 mm (4.1 in)
15 April 1921
May
62.2 mm (2.4 in)
17 May 1935
Jun
73.7 mm (2.9 in)
4 June 1921
Jul
51.8 mm (2.0 in)
30 July 1936
Aug
72.4 mm (2.9 in)
3 August 1929
Sep
78.2 mm (3.1 in)
2 September 1938
Oct
46.5 mm (1.8 in)
15 October 1947
Nov
35.6 mm (1.4 in)
1 November 1943
Dec
69.9 mm (2.8 in)
6 December 1913
Period of Record Coverage
1911 to 1964
Complete yearUnder 90 percent of days
54 years of record at Monument 2 WSW, 1911 to 1964. 10 years have data for under 90 percent of days and are left out of rankings: 1917, 1920, 1942, 1947, 1949, 1950, 1954, 1955 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 43 complete years at Monument 2 WSW, 1911 to 1963. Blue stripes are years cooler than the station's own mean of 7.6 C (45.7 F); red stripes are warmer. The coolest year was 1912, at 5.2 C (41.3 F), and the warmest was 1934, at 9.7 C (49.4 F). The strongest colour marks a difference of 2.5 C (4.5 F).
Annual mean temperature at Monument 2 WSW as warming stripes, 1911 to 1963
Year
Annual mean temperature
Difference from the station mean
1911
6.6 C
-0.99 C
1912
5.2 C
-2.42 C
1913
5.4 C
-2.24 C
1914
6.9 C
-0.67 C
1915
6.3 C
-1.34 C
1916
7.2 C
-0.39 C
1918
7.1 C
-0.54 C
1919
7.1 C
-0.47 C
1921
7.8 C
+0.25 C
1922
7.4 C
-0.24 C
1923
6.5 C
-1.07 C
1924
6.9 C
-0.67 C
1925
7.7 C
+0.13 C
1926
7.4 C
-0.21 C
1927
7.5 C
-0.14 C
1928
6.8 C
-0.78 C
1930
7.0 C
-0.61 C
1931
7.9 C
+0.35 C
1932
6.7 C
-0.88 C
1933
8.2 C
+0.59 C
1934
9.7 C
+2.10 C
1935
7.7 C
+0.06 C
1936
8.2 C
+0.56 C
1937
7.7 C
+0.11 C
1938
7.9 C
+0.27 C
1939
8.5 C
+0.88 C
1940
8.2 C
+0.61 C
1941
7.8 C
+0.16 C
1943
8.7 C
+1.10 C
1944
8.0 C
+0.42 C
1945
7.7 C
+0.09 C
1946
8.6 C
+1.03 C
1948
7.6 C
-0.02 C
1951
7.8 C
+0.16 C
1952
8.9 C
+1.26 C
1956
8.5 C
+0.90 C
1957
7.6 C
+0.03 C
1958
8.5 C
+0.93 C
1959
7.8 C
+0.22 C
1960
7.8 C
+0.24 C
1961
6.9 C
-0.69 C
1962
8.2 C
+0.59 C
1963
9.0 C
+1.45 C
The annual mean temperature here has risen by 0.4 C (0.2 to 0.5) per decade over 1911 to 1963. In Fahrenheit: 0.6 F (0.4 to 0.9) per decade. The slope is a straight line fitted to 43 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Monument 2 WSW
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.4 C (0.2 to 0.5) per decade
0.6 F (0.4 to 0.9) per decade
1911 to 1963
43
Rise
Mean daily maximum
0.4 C (0.2 to 0.6) per decade
0.7 F (0.4 to 1.0) per decade
1911 to 1963
43
Rise
Mean daily minimum
0.3 C (0.2 to 0.5) per decade
0.6 F (0.3 to 0.8) per decade
1911 to 1963
43
Rise
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
1911 to 1964
Yearly extremes at Monument 2 WSW: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
37.8 C (100.0 F)
1939
34.4 C (93.9 F)
54
Coldest night (TNn)
-40.0 C (-40.0 F)
1933
-26.7 C (-16.1 F)
54
Wettest day (Rx1day)
102.9 mm (4.1 in)
1921
38.5 mm (1.5 in)
54
Wettest five days (Rx5day)
122.7 mm (4.8 in)
1938
58.0 mm (2.3 in)
54
Longest dry spell (CDD)
59 days
1956
28 days
54
Hottest day (TXx)
The hottest day of the year at Monument 2 WSW, 1911 to 1964. The record is 37.8 C (100.0 F) in 1939, marked on the chart; the median year is 34.4 C (93.9 F).
Hottest day (TXx) at Monument 2 WSW by year
Year
Hottest day (TXx)
1911
32.8 C (91.0 F)
1912
29.4 C (84.9 F)
1913
32.2 C (90.0 F)
1914
30.0 C (86.0 F)
1915
30.6 C (87.1 F)
1916
31.7 C (89.1 F)
1917
32.2 C (90.0 F)
1918
33.3 C (91.9 F)
1919
33.3 C (91.9 F)
1920
35.6 C (96.1 F)
1921
32.2 C (90.0 F)
1922
34.4 C (93.9 F)
1923
33.3 C (91.9 F)
1924
34.4 C (93.9 F)
1925
36.7 C (98.1 F)
1926
34.4 C (93.9 F)
1927
33.3 C (91.9 F)
1928
35.0 C (95.0 F)
1929
36.1 C (97.0 F)
1930
33.9 C (93.0 F)
1931
35.6 C (96.1 F)
1932
36.7 C (98.1 F)
1933
34.4 C (93.9 F)
1934
37.2 C (99.0 F)
1935
33.9 C (93.0 F)
1936
36.7 C (98.1 F)
1937
35.6 C (96.1 F)
1938
36.7 C (98.1 F)
1939
37.8 C (100.0 F)
1940
36.7 C (98.1 F)
1941
30.6 C (87.1 F)
1942
31.1 C (88.0 F)
1943
33.9 C (93.0 F)
1944
33.9 C (93.0 F)
1945
31.1 C (88.0 F)
1946
33.3 C (91.9 F)
1947
33.3 C (91.9 F)
1948
33.3 C (91.9 F)
1949
33.9 C (93.0 F)
1950
34.4 C (93.9 F)
1951
36.7 C (98.1 F)
1952
36.1 C (97.0 F)
1953
34.4 C (93.9 F)
1954
37.2 C (99.0 F)
1955
33.9 C (93.0 F)
1956
35.6 C (96.1 F)
1957
33.3 C (91.9 F)
1958
35.0 C (95.0 F)
1959
36.1 C (97.0 F)
1960
36.7 C (98.1 F)
1961
32.2 C (90.0 F)
1962
35.0 C (95.0 F)
1963
36.7 C (98.1 F)
1964
34.4 C (93.9 F)
Coldest night (TNn)
The coldest night of the year at Monument 2 WSW, 1911 to 1964. The record is -40.0 C (-40.0 F) in 1933, marked on the chart; the median year is -26.7 C (-16.1 F).
Coldest night (TNn) at Monument 2 WSW by year
Year
Coldest night (TNn)
1911
-36.1 C (-33.0 F)
1912
-25.0 C (-13.0 F)
1913
-36.1 C (-33.0 F)
1914
-31.7 C (-25.1 F)
1915
-30.0 C (-22.0 F)
1916
-27.2 C (-17.0 F)
1917
-27.2 C (-17.0 F)
1918
-30.6 C (-23.1 F)
1919
-33.9 C (-29.0 F)
1920
-26.7 C (-16.1 F)
1921
-20.6 C (-5.1 F)
1922
-26.7 C (-16.1 F)
1923
-26.1 C (-15.0 F)
1924
-28.9 C (-20.0 F)
1925
-21.1 C (-6.0 F)
1926
-28.3 C (-18.9 F)
1927
-28.3 C (-18.9 F)
1928
-25.0 C (-13.0 F)
1929
-28.9 C (-20.0 F)
1930
-35.6 C (-32.1 F)
1931
-22.2 C (-8.0 F)
1932
-31.7 C (-25.1 F)
1933
-40.0 C (-40.0 F)
1934
-18.9 C (-2.0 F)
1935
-26.7 C (-16.1 F)
1936
-30.6 C (-23.1 F)
1937
-30.6 C (-23.1 F)
1938
-20.0 C (-4.0 F)
1939
-23.3 C (-9.9 F)
1940
-26.7 C (-16.1 F)
1941
-26.1 C (-15.0 F)
1942
-29.4 C (-20.9 F)
1943
-28.9 C (-20.0 F)
1944
-18.9 C (-2.0 F)
1945
-21.7 C (-7.1 F)
1946
-21.1 C (-6.0 F)
1947
-21.1 C (-6.0 F)
1948
-26.7 C (-16.1 F)
1949
-23.9 C (-11.0 F)
1950
-22.8 C (-9.0 F)
1951
-30.6 C (-23.1 F)
1952
-23.9 C (-11.0 F)
1953
-21.1 C (-6.0 F)
1954
-26.1 C (-15.0 F)
1955
-23.9 C (-11.0 F)
1956
-22.2 C (-8.0 F)
1957
-21.7 C (-7.1 F)
1958
-18.9 C (-2.0 F)
1959
-29.4 C (-20.9 F)
1960
-24.4 C (-11.9 F)
1961
-25.0 C (-13.0 F)
1962
-30.6 C (-23.1 F)
1963
-33.3 C (-27.9 F)
1964
-21.1 C (-6.0 F)
Wettest day (Rx1day)
The wettest day of the year at Monument 2 WSW, 1911 to 1964. The record is 102.9 mm (4.1 in) in 1921, marked on the chart; the median year is 38.5 mm (1.5 in).
Wettest day (Rx1day) at Monument 2 WSW by year
Year
Wettest day (Rx1day)
1911
25.4 mm (1.0 in)
1912
47.0 mm (1.9 in)
1913
69.9 mm (2.8 in)
1914
45.5 mm (1.8 in)
1915
34.3 mm (1.4 in)
1916
39.6 mm (1.6 in)
1917
19.8 mm (0.8 in)
1918
33.0 mm (1.3 in)
1919
26.4 mm (1.0 in)
1920
76.2 mm (3.0 in)
1921
102.9 mm (4.1 in)
1922
34.3 mm (1.4 in)
1923
39.1 mm (1.5 in)
1924
29.5 mm (1.2 in)
1925
29.5 mm (1.2 in)
1926
24.1 mm (0.9 in)
1927
38.6 mm (1.5 in)
1928
43.2 mm (1.7 in)
1929
72.4 mm (2.9 in)
1930
39.9 mm (1.6 in)
1931
24.1 mm (0.9 in)
1932
40.9 mm (1.6 in)
1933
39.9 mm (1.6 in)
1934
25.4 mm (1.0 in)
1935
62.2 mm (2.4 in)
1936
51.8 mm (2.0 in)
1937
30.5 mm (1.2 in)
1938
78.2 mm (3.1 in)
1939
21.8 mm (0.9 in)
1940
34.5 mm (1.4 in)
1941
45.5 mm (1.8 in)
1942
31.5 mm (1.2 in)
1943
35.6 mm (1.4 in)
1944
35.6 mm (1.4 in)
1945
49.3 mm (1.9 in)
1946
54.6 mm (2.1 in)
1947
46.5 mm (1.8 in)
1948
42.7 mm (1.7 in)
1949
36.3 mm (1.4 in)
1950
23.1 mm (0.9 in)
1951
27.7 mm (1.1 in)
1952
34.5 mm (1.4 in)
1953
41.7 mm (1.6 in)
1954
34.5 mm (1.4 in)
1955
60.2 mm (2.4 in)
1956
37.8 mm (1.5 in)
1957
66.0 mm (2.6 in)
1958
22.1 mm (0.9 in)
1959
38.4 mm (1.5 in)
1960
43.2 mm (1.7 in)
1961
43.4 mm (1.7 in)
1962
39.4 mm (1.6 in)
1963
36.8 mm (1.4 in)
1964
17.8 mm (0.7 in)
Wettest five days (Rx5day)
The wettest five days of the year at Monument 2 WSW, 1911 to 1964. The record is 122.7 mm (4.8 in) in 1938, marked on the chart; the median year is 58.0 mm (2.3 in).
Wettest five days (Rx5day) at Monument 2 WSW by year
Year
Wettest five days (Rx5day)
1911
43.5 mm (1.7 in)
1912
71.9 mm (2.8 in)
1913
76.8 mm (3.0 in)
1914
69.3 mm (2.7 in)
1915
51.6 mm (2.0 in)
1916
51.4 mm (2.0 in)
1917
32.7 mm (1.3 in)
1918
44.0 mm (1.7 in)
1919
55.9 mm (2.2 in)
1920
76.2 mm (3.0 in)
1921
110.3 mm (4.3 in)
1922
53.9 mm (2.1 in)
1923
82.7 mm (3.3 in)
1924
65.7 mm (2.6 in)
1925
60.8 mm (2.4 in)
1926
31.3 mm (1.2 in)
1927
44.4 mm (1.7 in)
1928
60.1 mm (2.4 in)
1929
92.9 mm (3.7 in)
1930
62.8 mm (2.5 in)
1931
44.0 mm (1.7 in)
1932
49.6 mm (2.0 in)
1933
86.7 mm (3.4 in)
1934
33.7 mm (1.3 in)
1935
107.2 mm (4.2 in)
1936
80.1 mm (3.2 in)
1937
45.7 mm (1.8 in)
1938
122.7 mm (4.8 in)
1939
33.3 mm (1.3 in)
1940
64.5 mm (2.5 in)
1941
70.8 mm (2.8 in)
1942
46.0 mm (1.8 in)
1943
40.9 mm (1.6 in)
1944
67.3 mm (2.6 in)
1945
58.3 mm (2.3 in)
1946
91.2 mm (3.6 in)
1947
93.5 mm (3.7 in)
1948
50.1 mm (2.0 in)
1949
68.1 mm (2.7 in)
1950
34.3 mm (1.4 in)
1951
37.9 mm (1.5 in)
1952
53.9 mm (2.1 in)
1953
76.8 mm (3.0 in)
1954
50.2 mm (2.0 in)
1955
87.4 mm (3.4 in)
1956
86.6 mm (3.4 in)
1957
72.9 mm (2.9 in)
1958
33.3 mm (1.3 in)
1959
47.0 mm (1.9 in)
1960
57.7 mm (2.3 in)
1961
72.7 mm (2.9 in)
1962
46.3 mm (1.8 in)
1963
53.8 mm (2.1 in)
1964
53.4 mm (2.1 in)
Longest dry spell (CDD)
The longest dry spell of the year at Monument 2 WSW, 1911 to 1964. The record is 59 days in 1956, marked on the chart; the median year is 28 days.
Longest dry spell (CDD) at Monument 2 WSW by year
Year
Longest dry spell (CDD)
1911
26 days
1912
18 days
1913
25 days
1914
27 days
1915
25 days
1916
31 days
1917
21 days
1918
25 days
1919
23 days
1920
25 days
1921
17 days
1922
48 days
1923
34 days
1924
28 days
1925
29 days
1926
25 days
1927
52 days
1928
22 days
1929
29 days
1930
24 days
1931
43 days
1932
24 days
1933
46 days
1934
38 days
1935
37 days
1936
56 days
1937
36 days
1938
23 days
1939
32 days
1940
21 days
1941
17 days
1942
26 days
1943
33 days
1944
35 days
1945
19 days
1946
21 days
1947
24 days
1948
32 days
1949
19 days
1950
52 days
1951
36 days
1952
30 days
1953
46 days
1954
31 days
1955
30 days
1956
59 days
1957
29 days
1958
22 days
1959
21 days
1960
25 days
1961
19 days
1962
32 days
1963
53 days
1964
22 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 Monument 2 WSW falls on 26 May and the median first autumn frost on 20 September, which leaves a median of 113 days between them.
Fitted over all years, the growing season changes by +3.7 days per decade at this station.
Frost dates and growing season at Monument 2 WSW
Measure
Median, all years
Earliest period
Recent period (1926 to 1963)
Recent against earliest
Fitted trend
Last spring frost
26 May
n/a
23 May
n/a
-1.5 days per decade
First autumn frost
20 September
n/a
23 September
n/a
+2.2 days per decade
Growing days
113 days
n/a
115 days
n/a
+3.7 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
43 years, 1912 to 1963
A day with at least 38.9 mm (1.5 in) of rain is expected about once in 2 years. A day with at least 86.7 mm (3.4 in) of rain is expected about once in 100 years.
Rainfall return levels at Monument 2 WSW: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
38.9 mm (1.5 in)
5 years
50.8 mm (2.0 in)
10 years
59.1 mm (2.3 in)
25 years
69.9 mm (2.8 in)
50 years
78.2 mm (3.1 in)
Longer than the 43 years of record
100 years
86.7 mm (3.4 in)
Longer than the 43 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, 43 years of values from 1912 to 1963.
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: 78.2 mm (3.1 in) in 1938; 72.4 mm (2.9 in) in 1929; 69.9 mm (2.8 in) in 1913.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Monument 2 WSW, at 1943. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1943 ran 0.4 C (0.7 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at Monument 2 WSW, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1943
+0.4
+0.7
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 Monument 2 WSW standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Monument 2 WSW 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.