Record envelope, standing records and threshold days for Del Bonita (USC00242301), Montana, United States, with 63 years of record.
Key Facts for Del Bonita
Del Bonita (USC00242301) is a weather station in Montana, United States at 49.00 latitude and -112.79 longitude, 1,322 m (4,337 ft) above sea level.
The station reports from 1951 to 2013, 63 years of record.
1,464 records set at Del Bonita still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Del Bonita set a daily record precipitation of 19.1 mm (0.8 in) on 30 July 2013.
About the Station
Location: Montana, United States, 49.00 latitude, -112.79 longitude.
Elevation: 1,322 m (4,337 ft).
Period of record: 1951 to 2013, 63 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 Del Bonita. 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 Del Bonita, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
16.7 C (62.1 F)
-41.7 C (-43.1 F)
n/a
n/a
Feb
20.6 C (69.1 F)
-38.9 C (-38.0 F)
n/a
n/a
Mar
23.9 C (75.0 F)
-34.4 C (-29.9 F)
n/a
n/a
Apr
28.3 C (82.9 F)
-22.8 C (-9.0 F)
n/a
n/a
May
32.2 C (90.0 F)
-13.9 C (7.0 F)
n/a
n/a
Jun
32.8 C (91.0 F)
-2.2 C (28.0 F)
n/a
n/a
Jul
36.7 C (98.1 F)
-0.6 C (30.9 F)
n/a
n/a
Aug
37.8 C (100.0 F)
-4.4 C (24.1 F)
n/a
n/a
Sep
35.0 C (95.0 F)
-11.7 C (10.9 F)
n/a
n/a
Oct
28.3 C (82.9 F)
-23.9 C (-11.0 F)
n/a
n/a
Nov
23.9 C (75.0 F)
-33.3 C (-27.9 F)
n/a
n/a
Dec
15.6 C (60.1 F)
-44.4 C (-47.9 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Del Bonita still stand. 1992 holds the most, with 56.
Standing records at Del Bonita by the year they were set
Year set
Standing records
1961
26
1962
41
1963
32
1964
26
1965
46
1966
28
1967
48
1968
35
1969
47
1970
26
1971
28
1972
38
1973
31
1974
15
1975
28
1976
19
1977
18
1978
6
1979
20
1980
27
1981
32
1982
27
1983
22
1984
29
1985
53
1986
46
1987
43
1988
29
1989
21
1990
30
1991
26
1992
56
1993
26
1994
36
1995
18
1996
30
1997
17
1998
15
1999
26
2000
25
2001
22
2002
56
2003
23
2004
25
2005
6
2006
3
2007
25
2008
23
2009
35
2010
14
2011
16
2012
20
2013
4
All-Time Record Progression
2 new records
2 all-time records were set at Del Bonita between 4 July 1998 and 9 June 2002. Each dot is a new record.
When Del Bonita set new all-time records
Date
Kind
Detail
1998-07-04
Record daily precipitation
Record daily precipitation 96.5 mm (3.8 in)
2002-06-09
Record daily precipitation
Record daily precipitation 127.0 mm (5.0 in)
Wettest Day of Each Month
Jun: 127.0 mm (5.0 in)
The wettest day on record for each calendar month at Del Bonita. The most was 127.0 mm (5.0 in) on 9 June 2002.
Record daily precipitation for each month at Del Bonita
Month
Record daily precipitation (mm)
Date
Jan
20.3 mm (0.8 in)
18 January 1975
Feb
12.7 mm (0.5 in)
3 February 1997
Mar
26.2 mm (1.0 in)
17 March 1981
Apr
50.8 mm (2.0 in)
23 April 2002
May
76.2 mm (3.0 in)
8 May 2002
Jun
127.0 mm (5.0 in)
9 June 2002
Jul
96.5 mm (3.8 in)
4 July 1998
Aug
48.8 mm (1.9 in)
17 August 1978
Sep
47.0 mm (1.9 in)
7 September 1978
Oct
29.5 mm (1.2 in)
7 October 1968
Nov
50.8 mm (2.0 in)
25 November 2001
Dec
25.4 mm (1.0 in)
3 December 2001
Period of Record Coverage
1960 to 2013
Complete yearUnder 90 percent of days
54 years of record at Del Bonita, 1960 to 2013. 10 years have data for under 90 percent of days and are left out of rankings: 1960, 1996, 2002, 2003, 2004, 2005, 2006, 2007 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 44 complete years at Del Bonita, 1961 to 2011. Blue stripes are years cooler than the station's own mean of 4.6 C (40.4 F); red stripes are warmer. The coolest year was 1982, at 2.8 C (37.0 F), and the warmest was 1987, at 7.1 C (44.8 F). The strongest colour marks a difference of 2.5 C (4.5 F).
Annual mean temperature at Del Bonita as warming stripes, 1961 to 2011
Year
Annual mean temperature
Difference from the station mean
1961
5.4 C
+0.80 C
1962
4.7 C
+0.09 C
1963
5.5 C
+0.86 C
1964
4.0 C
-0.64 C
1965
3.7 C
-0.98 C
1966
4.2 C
-0.48 C
1967
4.5 C
-0.12 C
1968
4.0 C
-0.63 C
1969
3.4 C
-1.23 C
1970
3.9 C
-0.75 C
1971
3.7 C
-0.90 C
1972
3.0 C
-1.62 C
1973
4.9 C
+0.27 C
1974
4.9 C
+0.29 C
1975
2.8 C
-1.86 C
1976
5.5 C
+0.82 C
1977
4.4 C
-0.22 C
1979
4.0 C
-0.69 C
1980
4.5 C
-0.11 C
1981
5.9 C
+1.30 C
1982
2.8 C
-1.88 C
1983
5.0 C
+0.37 C
1984
4.6 C
-0.06 C
1985
3.5 C
-1.13 C
1986
5.8 C
+1.12 C
1987
7.1 C
+2.45 C
1988
6.4 C
+1.71 C
1989
4.4 C
-0.20 C
1990
5.4 C
+0.74 C
1991
5.7 C
+1.03 C
1992
6.1 C
+1.42 C
1993
4.2 C
-0.42 C
1994
5.6 C
+0.92 C
1995
4.9 C
+0.23 C
1996
3.4 C
-1.26 C
1997
5.2 C
+0.58 C
1998
6.2 C
+1.54 C
1999
6.4 C
+1.78 C
2000
5.2 C
+0.60 C
2002
4.3 C
-0.34 C
2008
4.2 C
-0.42 C
2009
3.7 C
-0.96 C
2010
4.0 C
-0.60 C
2011
3.4 C
-1.24 C
The fitted trend in annual mean temperature here over 1961 to 2011 is 0.1 C (-0.1 to 0.3) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.2 F (-0.2 to 0.6) per decade. The slope is a straight line fitted to 44 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Del Bonita
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.1 C (-0.1 to 0.3) per decade
0.2 F (-0.2 to 0.6) per decade
1961 to 2011
44
Not clearly different from zero
Mean daily maximum
0.1 C (-0.2 to 0.3) per decade
0.1 F (-0.4 to 0.6) per decade
1961 to 2011
44
Not clearly different from zero
Mean daily minimum
0.1 C (-0.1 to 0.3) per decade
0.2 F (-0.1 to 0.6) per decade
1961 to 2011
44
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
1951 to 2013
Yearly extremes at Del Bonita: 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)
1961
32.8 C (91.0 F)
54
Coldest night (TNn)
-44.4 C (-47.9 F)
1968
-33.0 C (-27.5 F)
54
Wettest day (Rx1day)
127.0 mm (5.0 in)
2002
35.2 mm (1.4 in)
58
Wettest five days (Rx5day)
135.9 mm (5.4 in)
2002
52.9 mm (2.1 in)
58
Longest dry spell (CDD)
106 days
1960
36 days
58
Hottest day (TXx)
The hottest day of the year at Del Bonita, 1951 to 2013. The record is 37.8 C (100.0 F) in 1961, marked on the chart; the median year is 32.8 C (91.0 F).
Hottest day (TXx) at Del Bonita by year
Year
Hottest day (TXx)
1951
n/a
1952
n/a
1958
n/a
1959
n/a
1960
15.6 C (60.1 F)
1961
37.8 C (100.0 F)
1962
32.2 C (90.0 F)
1963
32.2 C (90.0 F)
1964
32.8 C (91.0 F)
1965
32.2 C (90.0 F)
1966
35.6 C (96.1 F)
1967
35.0 C (95.0 F)
1968
32.2 C (90.0 F)
1969
36.1 C (97.0 F)
1970
32.8 C (91.0 F)
1971
34.4 C (93.9 F)
1972
31.7 C (89.1 F)
1973
36.1 C (97.0 F)
1974
32.2 C (90.0 F)
1975
33.3 C (91.9 F)
1976
31.7 C (89.1 F)
1977
30.6 C (87.1 F)
1978
30.6 C (87.1 F)
1979
33.3 C (91.9 F)
1980
31.7 C (89.1 F)
1981
31.7 C (89.1 F)
1982
31.1 C (88.0 F)
1983
35.0 C (95.0 F)
1984
35.0 C (95.0 F)
1985
33.3 C (91.9 F)
1986
32.2 C (90.0 F)
1987
31.7 C (89.1 F)
1988
32.8 C (91.0 F)
1989
31.1 C (88.0 F)
1990
32.8 C (91.0 F)
1991
34.4 C (93.9 F)
1992
31.7 C (89.1 F)
1993
30.0 C (86.0 F)
1994
33.3 C (91.9 F)
1995
28.9 C (84.0 F)
1996
37.2 C (99.0 F)
1997
33.3 C (91.9 F)
1998
33.3 C (91.9 F)
1999
32.8 C (91.0 F)
2000
36.1 C (97.0 F)
2001
36.1 C (97.0 F)
2002
36.7 C (98.1 F)
2003
35.6 C (96.1 F)
2004
33.9 C (93.0 F)
2005
31.7 C (89.1 F)
2006
33.3 C (91.9 F)
2007
36.1 C (97.0 F)
2008
33.3 C (91.9 F)
2009
32.8 C (91.0 F)
2010
32.2 C (90.0 F)
2011
33.3 C (91.9 F)
2012
32.8 C (91.0 F)
2013
33.9 C (93.0 F)
Coldest night (TNn)
The coldest night of the year at Del Bonita, 1951 to 2013. The record is -44.4 C (-47.9 F) in 1968, marked on the chart; the median year is -33.0 C (-27.5 F).
Coldest night (TNn) at Del Bonita by year
Year
Coldest night (TNn)
1951
n/a
1952
n/a
1958
n/a
1959
n/a
1960
-22.2 C (-8.0 F)
1961
-31.1 C (-24.0 F)
1962
-33.3 C (-27.9 F)
1963
-33.9 C (-29.0 F)
1964
-35.6 C (-32.1 F)
1965
-31.1 C (-24.0 F)
1966
-32.8 C (-27.0 F)
1967
-32.8 C (-27.0 F)
1968
-44.4 C (-47.9 F)
1969
-36.7 C (-34.1 F)
1970
-35.0 C (-31.0 F)
1971
-41.7 C (-43.1 F)
1972
-39.4 C (-38.9 F)
1973
-30.0 C (-22.0 F)
1974
-32.2 C (-26.0 F)
1975
-31.7 C (-25.1 F)
1976
-31.1 C (-24.0 F)
1977
-36.7 C (-34.1 F)
1978
-33.3 C (-27.9 F)
1979
-31.7 C (-25.1 F)
1980
-32.2 C (-26.0 F)
1981
-32.2 C (-26.0 F)
1982
-34.4 C (-29.9 F)
1983
-38.9 C (-38.0 F)
1984
-35.0 C (-31.0 F)
1985
-33.3 C (-27.9 F)
1986
-37.8 C (-36.0 F)
1987
-23.9 C (-11.0 F)
1988
-29.4 C (-20.9 F)
1989
-38.9 C (-38.0 F)
1990
-35.0 C (-31.0 F)
1991
-29.4 C (-20.9 F)
1992
-38.3 C (-36.9 F)
1993
-29.4 C (-20.9 F)
1994
-35.6 C (-32.1 F)
1995
-32.8 C (-27.0 F)
1996
-37.2 C (-35.0 F)
1997
-32.2 C (-26.0 F)
1998
-33.9 C (-29.0 F)
1999
-25.0 C (-13.0 F)
2000
-31.1 C (-24.0 F)
2001
-25.6 C (-14.1 F)
2002
-34.4 C (-29.9 F)
2003
-29.4 C (-20.9 F)
2004
-33.3 C (-27.9 F)
2005
-26.1 C (-15.0 F)
2006
-25.0 C (-13.0 F)
2007
-23.9 C (-11.0 F)
2008
-34.4 C (-29.9 F)
2009
-33.3 C (-27.9 F)
2010
-28.9 C (-20.0 F)
2011
-33.3 C (-27.9 F)
2012
-37.8 C (-36.0 F)
2013
-22.2 C (-8.0 F)
Wettest day (Rx1day)
The wettest day of the year at Del Bonita, 1951 to 2013. The record is 127.0 mm (5.0 in) in 2002, marked on the chart; the median year is 35.2 mm (1.4 in).
Wettest day (Rx1day) at Del Bonita by year
Year
Wettest day (Rx1day)
1951
77.7 mm (3.1 in)
1952
20.6 mm (0.8 in)
1958
30.5 mm (1.2 in)
1959
34.0 mm (1.3 in)
1960
27.9 mm (1.1 in)
1961
36.1 mm (1.4 in)
1962
28.4 mm (1.1 in)
1963
67.1 mm (2.6 in)
1964
74.4 mm (2.9 in)
1965
48.5 mm (1.9 in)
1966
57.7 mm (2.3 in)
1967
27.9 mm (1.1 in)
1968
32.5 mm (1.3 in)
1969
45.7 mm (1.8 in)
1970
61.5 mm (2.4 in)
1971
27.7 mm (1.1 in)
1972
29.2 mm (1.1 in)
1973
32.5 mm (1.3 in)
1974
37.3 mm (1.5 in)
1975
53.8 mm (2.1 in)
1976
24.1 mm (0.9 in)
1977
33.0 mm (1.3 in)
1978
48.8 mm (1.9 in)
1979
20.8 mm (0.8 in)
1980
39.1 mm (1.5 in)
1981
37.8 mm (1.5 in)
1982
27.9 mm (1.1 in)
1983
22.9 mm (0.9 in)
1984
24.9 mm (1.0 in)
1985
57.2 mm (2.3 in)
1986
34.3 mm (1.4 in)
1987
44.5 mm (1.8 in)
1988
24.1 mm (0.9 in)
1989
39.4 mm (1.6 in)
1990
19.1 mm (0.8 in)
1991
40.6 mm (1.6 in)
1992
21.8 mm (0.9 in)
1993
43.4 mm (1.7 in)
1994
28.2 mm (1.1 in)
1995
69.3 mm (2.7 in)
1996
54.1 mm (2.1 in)
1997
45.7 mm (1.8 in)
1998
96.5 mm (3.8 in)
1999
27.9 mm (1.1 in)
2000
24.1 mm (0.9 in)
2001
50.8 mm (2.0 in)
2002
127.0 mm (5.0 in)
2003
15.2 mm (0.6 in)
2004
41.9 mm (1.6 in)
2005
50.8 mm (2.0 in)
2006
25.4 mm (1.0 in)
2007
18.5 mm (0.7 in)
2008
39.1 mm (1.5 in)
2009
39.4 mm (1.6 in)
2010
102.1 mm (4.0 in)
2011
26.7 mm (1.1 in)
2012
30.5 mm (1.2 in)
2013
19.1 mm (0.8 in)
Wettest five days (Rx5day)
The wettest five days of the year at Del Bonita, 1951 to 2013. The record is 135.9 mm (5.4 in) in 2002, marked on the chart; the median year is 52.9 mm (2.1 in).
Wettest five days (Rx5day) at Del Bonita by year
Year
Wettest five days (Rx5day)
1951
102.9 mm (4.1 in)
1952
27.2 mm (1.1 in)
1958
33.3 mm (1.3 in)
1959
52.3 mm (2.1 in)
1960
75.9 mm (3.0 in)
1961
50.1 mm (2.0 in)
1962
51.3 mm (2.0 in)
1963
72.7 mm (2.9 in)
1964
117.9 mm (4.6 in)
1965
98.8 mm (3.9 in)
1966
75.4 mm (3.0 in)
1967
48.3 mm (1.9 in)
1968
41.7 mm (1.6 in)
1969
108.2 mm (4.3 in)
1970
116.6 mm (4.6 in)
1971
51.0 mm (2.0 in)
1972
37.8 mm (1.5 in)
1973
37.6 mm (1.5 in)
1974
44.7 mm (1.8 in)
1975
113.7 mm (4.5 in)
1976
58.9 mm (2.3 in)
1977
43.9 mm (1.7 in)
1978
101.1 mm (4.0 in)
1979
35.8 mm (1.4 in)
1980
105.1 mm (4.1 in)
1981
78.3 mm (3.1 in)
1982
46.7 mm (1.8 in)
1983
25.7 mm (1.0 in)
1984
42.4 mm (1.7 in)
1985
75.0 mm (3.0 in)
1986
40.9 mm (1.6 in)
1987
52.3 mm (2.1 in)
1988
40.3 mm (1.6 in)
1989
78.5 mm (3.1 in)
1990
36.3 mm (1.4 in)
1991
102.8 mm (4.0 in)
1992
51.5 mm (2.0 in)
1993
64.8 mm (2.6 in)
1994
63.5 mm (2.5 in)
1995
120.1 mm (4.7 in)
1996
59.2 mm (2.3 in)
1997
66.6 mm (2.6 in)
1998
112.5 mm (4.4 in)
1999
38.6 mm (1.5 in)
2000
39.3 mm (1.5 in)
2001
60.5 mm (2.4 in)
2002
135.9 mm (5.4 in)
2003
25.7 mm (1.0 in)
2004
87.8 mm (3.5 in)
2005
53.4 mm (2.1 in)
2006
58.5 mm (2.3 in)
2007
18.5 mm (0.7 in)
2008
88.6 mm (3.5 in)
2009
42.2 mm (1.7 in)
2010
124.5 mm (4.9 in)
2011
46.0 mm (1.8 in)
2012
30.5 mm (1.2 in)
2013
38.2 mm (1.5 in)
Longest dry spell (CDD)
The longest dry spell of the year at Del Bonita, 1951 to 2013. The record is 106 days in 1960, marked on the chart; the median year is 36 days.
Longest dry spell (CDD) at Del Bonita by year
Year
Longest dry spell (CDD)
1951
18 days
1952
28 days
1958
19 days
1959
29 days
1960
106 days
1961
45 days
1962
50 days
1963
69 days
1964
35 days
1965
43 days
1966
40 days
1967
31 days
1968
24 days
1969
46 days
1970
31 days
1971
20 days
1972
20 days
1973
33 days
1974
27 days
1975
18 days
1976
50 days
1977
42 days
1978
30 days
1979
25 days
1980
41 days
1981
36 days
1982
29 days
1983
38 days
1984
36 days
1985
28 days
1986
29 days
1987
49 days
1988
59 days
1989
40 days
1990
38 days
1991
25 days
1992
51 days
1993
35 days
1994
41 days
1995
39 days
1996
36 days
1997
48 days
1998
33 days
1999
71 days
2000
65 days
2001
59 days
2002
32 days
2003
32 days
2004
66 days
2005
28 days
2006
28 days
2007
33 days
2008
49 days
2009
49 days
2010
26 days
2011
41 days
2012
22 days
2013
11 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
44 years with a frost
Across 44 years with a frost, the median last spring frost at Del Bonita falls on 30 May and the median first autumn frost on 12 September, which leaves a median of 103 days between them.
Fitted over all years, the growing season changes by -0.3 days per decade at this station.
Frost dates and growing season at Del Bonita
Measure
Median, all years
Earliest period
Recent period (1975 to 2011)
Recent against earliest
Fitted trend
Last spring frost
30 May
n/a
30 May
n/a
-0.6 days per decade
First autumn frost
12 September
n/a
12 September
n/a
-1.0 days per decade
Growing days
103 days
n/a
105 days
n/a
-0.3 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
47 years, 1952 to 2011
A day with at least 36.2 mm (1.4 in) of rain is expected about once in 2 years. A day with at least 114.1 mm (4.5 in) of rain is expected about once in 100 years.
Rainfall return levels at Del Bonita: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
36.2 mm (1.4 in)
5 years
51.8 mm (2.0 in)
10 years
63.9 mm (2.5 in)
25 years
81.7 mm (3.2 in)
50 years
97.0 mm (3.8 in)
Longer than the 47 years of record
100 years
114.1 mm (4.5 in)
Longer than the 47 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, 47 years of values from 1952 to 2011.
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: 102.1 mm (4.0 in) in 2010; 96.5 mm (3.8 in) in 1998; 74.4 mm (2.9 in) in 1964.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Del Bonita, at 2002. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 2002 ran 0.4 C (0.7 F) lower than in the years before (likely change).
Suspected changes in the annual mean temperature at Del Bonita, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
2002
-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 Del Bonita standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Del Bonita 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.