Record envelope, standing records and threshold days for Bonesteel (USC00390778), South Dakota, United States, with 49 years of record.
Key Facts for Bonesteel
Bonesteel (USC00390778) is a weather station in South Dakota, United States at 43.08 latitude and -98.95 longitude, 605 m (1,985 ft) above sea level.
The station reports from 1956 to 2004, 49 years of record.
1,464 records set at Bonesteel still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Bonesteel tied a daily record high minimum temperature of 20.0 C (68.0 F) on 8 June 2004.
About the Station
Location: South Dakota, United States, 43.08 latitude, -98.95 longitude.
Elevation: 605 m (1,985 ft).
Period of record: 1956 to 2004, 49 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 Bonesteel. 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 Bonesteel, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
22.2 C (72.0 F)
-35.6 C (-32.1 F)
n/a
n/a
Feb
24.4 C (75.9 F)
-33.9 C (-29.0 F)
n/a
n/a
Mar
30.6 C (87.1 F)
-30.6 C (-23.1 F)
n/a
n/a
Apr
35.0 C (95.0 F)
-16.7 C (1.9 F)
n/a
n/a
May
38.9 C (102.0 F)
-7.8 C (18.0 F)
n/a
n/a
Jun
40.6 C (105.1 F)
1.7 C (35.1 F)
n/a
n/a
Jul
42.8 C (109.0 F)
4.4 C (39.9 F)
n/a
n/a
Aug
42.8 C (109.0 F)
0.6 C (33.1 F)
n/a
n/a
Sep
39.4 C (102.9 F)
-7.2 C (19.0 F)
n/a
n/a
Oct
35.0 C (95.0 F)
-12.2 C (10.0 F)
n/a
n/a
Nov
28.3 C (82.9 F)
-30.0 C (-22.0 F)
n/a
n/a
Dec
22.8 C (73.0 F)
-33.3 C (-27.9 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Bonesteel still stand. 1989 holds the most, with 47.
Standing records at Bonesteel by the year they were set
Year set
Standing records
1956
22
1957
18
1958
20
1959
30
1960
20
1961
16
1962
44
1963
36
1964
38
1965
42
1966
45
1967
37
1968
32
1969
30
1970
33
1971
26
1972
37
1973
19
1974
36
1975
28
1976
44
1977
25
1978
21
1979
24
1980
34
1981
23
1982
38
1983
35
1984
13
1985
44
1986
26
1987
29
1988
27
1989
47
1990
33
1991
34
1992
40
1993
22
1994
24
1995
26
1996
25
1997
36
1998
33
1999
21
2000
34
2001
25
2002
38
2003
26
2004
8
All-Time Record Progression
3 new records
3 all-time records were set at Bonesteel between 3 February 1989 and 22 December 1989. Each dot is a new record.
When Bonesteel set new all-time records
Date
Kind
Detail
1989-02-03
Record low maximum temperature
Record low maximum temperature -26.1 C (-15.0 F)
1989-07-15
Record daily precipitation
Record daily precipitation 127.0 mm (5.0 in)
1989-12-22
Record low maximum temperature
Record low maximum temperature -26.7 C (-16.1 F)
Wettest Day of Each Month
Jul: 127.0 mm (5.0 in)
The wettest day on record for each calendar month at Bonesteel. The most was 127.0 mm (5.0 in) on 15 July 1989.
Record daily precipitation for each month at Bonesteel
Month
Record daily precipitation (mm)
Date
Jan
27.9 mm (1.1 in)
30 January 2001
Feb
29.2 mm (1.1 in)
19 February 1971
Mar
47.0 mm (1.9 in)
10 March 1977
Apr
66.0 mm (2.6 in)
12 April 2001
May
99.6 mm (3.9 in)
27 May 1963
Jun
94.0 mm (3.7 in)
9 June 1974
Jul
127.0 mm (5.0 in)
15 July 1989
Aug
103.1 mm (4.1 in)
30 August 1971
Sep
86.4 mm (3.4 in)
16 September 1987
Oct
58.4 mm (2.3 in)
16 October 1980
Nov
58.4 mm (2.3 in)
11 November 1982
Dec
48.3 mm (1.9 in)
1 December 1981
Period of Record Coverage
1956 to 2004
Complete yearUnder 90 percent of days
49 years of record at Bonesteel, 1956 to 2004. 6 years have data for under 90 percent of days and are left out of rankings: 1956, 1958, 1959, 1983, 1984, 2004.
Cooler than the station meanWarmer than the station mean
One stripe for each of 41 complete years at Bonesteel, 1957 to 2003. Blue stripes are years cooler than the station's own mean of 8.7 C (47.6 F); red stripes are warmer. The coolest year was 1996, at 6.2 C (43.2 F), and the warmest was 1981, at 10.6 C (51.1 F). The strongest colour marks a difference of 2.5 C (4.5 F).
Annual mean temperature at Bonesteel as warming stripes, 1957 to 2003
Year
Annual mean temperature
Difference from the station mean
1957
8.6 C
-0.12 C
1960
8.0 C
-0.70 C
1961
8.5 C
-0.16 C
1962
8.6 C
-0.10 C
1963
9.8 C
+1.11 C
1964
8.9 C
+0.18 C
1965
8.1 C
-0.61 C
1966
7.9 C
-0.76 C
1967
8.8 C
+0.15 C
1968
8.8 C
+0.16 C
1969
8.2 C
-0.53 C
1970
8.8 C
+0.11 C
1971
8.8 C
+0.12 C
1972
8.1 C
-0.56 C
1973
9.7 C
+1.01 C
1974
10.0 C
+1.27 C
1975
8.9 C
+0.21 C
1976
9.9 C
+1.18 C
1977
9.2 C
+0.49 C
1978
7.5 C
-1.20 C
1979
8.0 C
-0.70 C
1980
9.9 C
+1.21 C
1981
10.6 C
+1.93 C
1986
8.6 C
-0.13 C
1987
9.6 C
+0.96 C
1988
8.3 C
-0.40 C
1989
7.7 C
-1.02 C
1990
9.2 C
+0.47 C
1991
9.1 C
+0.45 C
1992
8.0 C
-0.73 C
1993
6.5 C
-2.14 C
1994
7.9 C
-0.76 C
1995
7.7 C
-1.03 C
1996
6.2 C
-2.45 C
1997
8.3 C
-0.43 C
1998
9.5 C
+0.85 C
1999
9.8 C
+1.07 C
2000
9.0 C
+0.34 C
2001
9.1 C
+0.39 C
2002
9.1 C
+0.45 C
2003
9.0 C
+0.34 C
The fitted trend in annual mean temperature here over 1957 to 2003 is -0.04 C (-0.25 to 0.17) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: -0.1 F (-0.5 to 0.3) per decade. The slope is a straight line fitted to 41 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Bonesteel
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
-0.04 C (-0.25 to 0.17) per decade
-0.1 F (-0.5 to 0.3) per decade
1957 to 2003
41
Not clearly different from zero
Mean daily maximum
-0.24 C (-0.52 to 0.05) per decade
-0.4 F (-0.9 to 0.1) per decade
1957 to 2003
41
Not clearly different from zero
Mean daily minimum
0.16 C (-0.04 to 0.35) per decade
0.3 F (-0.1 to 0.6) per decade
1957 to 2003
41
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
1956 to 2004
Yearly extremes at Bonesteel: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
42.8 C (109.0 F)
1966
38.9 C (102.0 F)
49
Coldest night (TNn)
-35.6 C (-32.1 F)
1966
-28.9 C (-20.0 F)
49
Wettest day (Rx1day)
127.0 mm (5.0 in)
1989
56.4 mm (2.2 in)
49
Wettest five days (Rx5day)
167.6 mm (6.6 in)
1986
81.6 mm (3.2 in)
49
Longest dry spell (CDD)
79 days
1962
31 days
49
Hottest day (TXx)
The hottest day of the year at Bonesteel, 1956 to 2004. The record is 42.8 C (109.0 F) in 1966, marked on the chart; the median year is 38.9 C (102.0 F).
Hottest day (TXx) at Bonesteel by year
Year
Hottest day (TXx)
1956
39.4 C (102.9 F)
1957
38.3 C (100.9 F)
1958
37.8 C (100.0 F)
1959
38.9 C (102.0 F)
1960
38.3 C (100.9 F)
1961
40.6 C (105.1 F)
1962
34.4 C (93.9 F)
1963
39.4 C (102.9 F)
1964
40.6 C (105.1 F)
1965
40.6 C (105.1 F)
1966
42.8 C (109.0 F)
1967
40.6 C (105.1 F)
1968
39.4 C (102.9 F)
1969
37.8 C (100.0 F)
1970
40.0 C (104.0 F)
1971
40.6 C (105.1 F)
1972
35.0 C (95.0 F)
1973
38.9 C (102.0 F)
1974
39.4 C (102.9 F)
1975
38.9 C (102.0 F)
1976
41.1 C (106.0 F)
1977
36.7 C (98.1 F)
1978
39.4 C (102.9 F)
1979
39.4 C (102.9 F)
1980
41.1 C (106.0 F)
1981
40.0 C (104.0 F)
1982
42.8 C (109.0 F)
1983
39.4 C (102.9 F)
1984
38.9 C (102.0 F)
1985
38.9 C (102.0 F)
1986
36.1 C (97.0 F)
1987
38.9 C (102.0 F)
1988
40.6 C (105.1 F)
1989
38.9 C (102.0 F)
1990
38.3 C (100.9 F)
1991
39.4 C (102.9 F)
1992
35.0 C (95.0 F)
1993
35.0 C (95.0 F)
1994
35.0 C (95.0 F)
1995
40.6 C (105.1 F)
1996
36.1 C (97.0 F)
1997
37.2 C (99.0 F)
1998
37.2 C (99.0 F)
1999
37.2 C (99.0 F)
2000
40.0 C (104.0 F)
2001
37.8 C (100.0 F)
2002
42.2 C (108.0 F)
2003
39.4 C (102.9 F)
2004
37.2 C (99.0 F)
Coldest night (TNn)
The coldest night of the year at Bonesteel, 1956 to 2004. The record is -35.6 C (-32.1 F) in 1966, marked on the chart; the median year is -28.9 C (-20.0 F).
Coldest night (TNn) at Bonesteel by year
Year
Coldest night (TNn)
1956
-20.6 C (-5.1 F)
1957
-27.8 C (-18.0 F)
1958
-26.1 C (-15.0 F)
1959
-32.8 C (-27.0 F)
1960
-30.6 C (-23.1 F)
1961
-30.0 C (-22.0 F)
1962
-31.7 C (-25.1 F)
1963
-30.6 C (-23.1 F)
1964
-29.4 C (-20.9 F)
1965
-27.8 C (-18.0 F)
1966
-35.6 C (-32.1 F)
1967
-30.0 C (-22.0 F)
1968
-31.1 C (-24.0 F)
1969
-29.4 C (-20.9 F)
1970
-34.4 C (-29.9 F)
1971
-28.9 C (-20.0 F)
1972
-28.9 C (-20.0 F)
1973
-27.8 C (-18.0 F)
1974
-32.2 C (-26.0 F)
1975
-32.2 C (-26.0 F)
1976
-29.4 C (-20.9 F)
1977
-32.2 C (-26.0 F)
1978
-30.0 C (-22.0 F)
1979
-31.1 C (-24.0 F)
1980
-27.8 C (-18.0 F)
1981
-31.7 C (-25.1 F)
1982
-33.3 C (-27.9 F)
1983
-14.4 C (6.1 F)
1984
-21.1 C (-6.0 F)
1985
-27.2 C (-17.0 F)
1986
-25.6 C (-14.1 F)
1987
-21.1 C (-6.0 F)
1988
-30.6 C (-23.1 F)
1989
-33.3 C (-27.9 F)
1990
-31.1 C (-24.0 F)
1991
-22.2 C (-8.0 F)
1992
-23.3 C (-9.9 F)
1993
-26.7 C (-16.1 F)
1994
-33.9 C (-29.0 F)
1995
-22.2 C (-8.0 F)
1996
-33.3 C (-27.9 F)
1997
-27.8 C (-18.0 F)
1998
-28.3 C (-18.9 F)
1999
-27.8 C (-18.0 F)
2000
-26.1 C (-15.0 F)
2001
-24.4 C (-11.9 F)
2002
-20.6 C (-5.1 F)
2003
-25.6 C (-14.1 F)
2004
-23.9 C (-11.0 F)
Wettest day (Rx1day)
The wettest day of the year at Bonesteel, 1956 to 2004. The record is 127.0 mm (5.0 in) in 1989, marked on the chart; the median year is 56.4 mm (2.2 in).
Wettest day (Rx1day) at Bonesteel by year
Year
Wettest day (Rx1day)
1956
27.7 mm (1.1 in)
1957
39.4 mm (1.6 in)
1958
41.1 mm (1.6 in)
1959
44.5 mm (1.8 in)
1960
52.1 mm (2.1 in)
1961
56.4 mm (2.2 in)
1962
54.6 mm (2.1 in)
1963
99.6 mm (3.9 in)
1964
71.6 mm (2.8 in)
1965
57.2 mm (2.3 in)
1966
70.4 mm (2.8 in)
1967
57.9 mm (2.3 in)
1968
58.7 mm (2.3 in)
1969
32.0 mm (1.3 in)
1970
46.5 mm (1.8 in)
1971
103.1 mm (4.1 in)
1972
61.0 mm (2.4 in)
1973
73.2 mm (2.9 in)
1974
94.0 mm (3.7 in)
1975
35.8 mm (1.4 in)
1976
41.9 mm (1.6 in)
1977
67.3 mm (2.6 in)
1978
49.5 mm (1.9 in)
1979
45.7 mm (1.8 in)
1980
58.4 mm (2.3 in)
1981
48.3 mm (1.9 in)
1982
58.4 mm (2.3 in)
1983
57.9 mm (2.3 in)
1984
68.6 mm (2.7 in)
1985
50.8 mm (2.0 in)
1986
78.7 mm (3.1 in)
1987
86.4 mm (3.4 in)
1988
55.9 mm (2.2 in)
1989
127.0 mm (5.0 in)
1990
31.8 mm (1.3 in)
1991
55.9 mm (2.2 in)
1992
62.2 mm (2.4 in)
1993
55.9 mm (2.2 in)
1994
55.9 mm (2.2 in)
1995
81.3 mm (3.2 in)
1996
81.3 mm (3.2 in)
1997
53.3 mm (2.1 in)
1998
39.4 mm (1.6 in)
1999
62.2 mm (2.4 in)
2000
66.0 mm (2.6 in)
2001
66.0 mm (2.6 in)
2002
34.3 mm (1.4 in)
2003
47.0 mm (1.9 in)
2004
36.8 mm (1.4 in)
Wettest five days (Rx5day)
The wettest five days of the year at Bonesteel, 1956 to 2004. The record is 167.6 mm (6.6 in) in 1986, marked on the chart; the median year is 81.6 mm (3.2 in).
Wettest five days (Rx5day) at Bonesteel by year
Year
Wettest five days (Rx5day)
1956
39.1 mm (1.5 in)
1957
74.9 mm (2.9 in)
1958
47.3 mm (1.9 in)
1959
53.9 mm (2.1 in)
1960
78.2 mm (3.1 in)
1961
82.6 mm (3.3 in)
1962
107.1 mm (4.2 in)
1963
107.7 mm (4.2 in)
1964
79.1 mm (3.1 in)
1965
69.9 mm (2.8 in)
1966
81.6 mm (3.2 in)
1967
100.5 mm (4.0 in)
1968
86.3 mm (3.4 in)
1969
54.6 mm (2.1 in)
1970
74.4 mm (2.9 in)
1971
103.1 mm (4.1 in)
1972
103.1 mm (4.1 in)
1973
109.5 mm (4.3 in)
1974
94.0 mm (3.7 in)
1975
48.8 mm (1.9 in)
1976
57.0 mm (2.2 in)
1977
108.0 mm (4.3 in)
1978
72.4 mm (2.9 in)
1979
73.7 mm (2.9 in)
1980
58.4 mm (2.3 in)
1981
50.8 mm (2.0 in)
1982
105.4 mm (4.1 in)
1983
141.7 mm (5.6 in)
1984
68.6 mm (2.7 in)
1985
90.1 mm (3.5 in)
1986
167.6 mm (6.6 in)
1987
118.1 mm (4.6 in)
1988
96.6 mm (3.8 in)
1989
128.3 mm (5.1 in)
1990
53.8 mm (2.1 in)
1991
83.9 mm (3.3 in)
1992
102.8 mm (4.0 in)
1993
76.2 mm (3.0 in)
1994
81.3 mm (3.2 in)
1995
106.6 mm (4.2 in)
1996
149.8 mm (5.9 in)
1997
73.7 mm (2.9 in)
1998
86.4 mm (3.4 in)
1999
101.6 mm (4.0 in)
2000
66.0 mm (2.6 in)
2001
86.3 mm (3.4 in)
2002
42.0 mm (1.7 in)
2003
74.9 mm (2.9 in)
2004
47.0 mm (1.9 in)
Longest dry spell (CDD)
The longest dry spell of the year at Bonesteel, 1956 to 2004. The record is 79 days in 1962, marked on the chart; the median year is 31 days.
Longest dry spell (CDD) at Bonesteel by year
Year
Longest dry spell (CDD)
1956
27 days
1957
45 days
1958
24 days
1959
20 days
1960
27 days
1961
43 days
1962
79 days
1963
49 days
1964
40 days
1965
22 days
1966
24 days
1967
66 days
1968
27 days
1969
21 days
1970
47 days
1971
29 days
1972
31 days
1973
32 days
1974
46 days
1975
25 days
1976
47 days
1977
48 days
1978
44 days
1979
38 days
1980
45 days
1981
38 days
1982
23 days
1983
52 days
1984
37 days
1985
43 days
1986
48 days
1987
28 days
1988
22 days
1989
38 days
1990
24 days
1991
29 days
1992
30 days
1993
23 days
1994
31 days
1995
23 days
1996
40 days
1997
26 days
1998
39 days
1999
60 days
2000
30 days
2001
41 days
2002
28 days
2003
26 days
2004
23 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
41 years with a frost
Across 41 years with a frost, the median last spring frost at Bonesteel falls on 7 May and the median first autumn frost on 4 October, which leaves a median of 151 days between them.
Fitted over all years, the growing season changes by +3.1 days per decade at this station.
Frost dates and growing season at Bonesteel
Measure
Median, all years
Earliest period
Recent period (1970 to 2003)
Recent against earliest
Fitted trend
Last spring frost
7 May
n/a
5 May
n/a
-1.9 days per decade
First autumn frost
4 October
n/a
5 October
n/a
+1.2 days per decade
Growing days
151 days
n/a
151 days
n/a
+3.1 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, 1957 to 2003
A day with at least 57.3 mm (2.3 in) of rain is expected about once in 2 years. A day with at least 127.5 mm (5.0 in) of rain is expected about once in 100 years.
Rainfall return levels at Bonesteel: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
57.3 mm (2.3 in)
5 years
74.8 mm (2.9 in)
10 years
86.9 mm (3.4 in)
25 years
102.8 mm (4.0 in)
50 years
115.0 mm (4.5 in)
Longer than the 43 years of record
100 years
127.5 mm (5.0 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 1957 to 2003.
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: 127.0 mm (5.0 in) in 1989; 103.1 mm (4.1 in) in 1971; 99.6 mm (3.9 in) in 1963.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Bonesteel, at 1993. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1993 ran 0.4 C (0.7 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at Bonesteel, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1993
+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 Bonesteel standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Bonesteel 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.