Record envelope, standing records and threshold days for Castle Hot Springs (USC00021353), Arizona, United States, with 103 years of record.
Key Facts for Castle Hot Springs
Castle Hot Springs (USC00021353) is a weather station in Arizona, United States at 33.98 latitude and -112.36 longitude, 607 m (1,990 ft) above sea level.
The station reports from 1916 to 2018, 103 years of record.
1,464 records set at Castle Hot Springs still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Castle Hot Springs set a daily record high maximum temperature of 40.6 C (105.1 F) on 9 May 2018.
About the Station
Location: Arizona, United States, 33.98 latitude, -112.36 longitude.
Elevation: 607 m (1,990 ft).
Period of record: 1916 to 2018, 103 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 Castle Hot Springs. 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 Castle Hot Springs, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
30.6 C (87.1 F)
-8.3 C (17.1 F)
n/a
n/a
Feb
32.8 C (91.0 F)
-6.7 C (19.9 F)
n/a
n/a
Mar
35.6 C (96.1 F)
-4.4 C (24.1 F)
n/a
n/a
Apr
38.3 C (100.9 F)
0.0 C (32.0 F)
n/a
n/a
May
43.3 C (109.9 F)
3.3 C (37.9 F)
n/a
n/a
Jun
48.3 C (118.9 F)
8.3 C (46.9 F)
n/a
n/a
Jul
48.9 C (120.0 F)
11.7 C (53.1 F)
n/a
n/a
Aug
45.0 C (113.0 F)
14.4 C (57.9 F)
n/a
n/a
Sep
43.9 C (111.0 F)
8.3 C (46.9 F)
n/a
n/a
Oct
40.0 C (104.0 F)
0.0 C (32.0 F)
n/a
n/a
Nov
34.4 C (93.9 F)
-3.9 C (25.0 F)
n/a
n/a
Dec
29.4 C (84.9 F)
-5.6 C (21.9 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Castle Hot Springs still stand. 1936 holds the most, with 61.
Standing records at Castle Hot Springs by the year they were set
Year set
Standing records
1916
46
1917
19
1918
7
1928
25
1929
22
1930
34
1931
36
1932
32
1933
37
1934
37
1935
29
1936
61
1959
16
1960
14
1961
11
1962
22
1963
17
1964
12
1965
33
1966
14
1967
16
1968
18
1969
24
1970
20
1971
48
1972
23
1973
21
1974
16
1975
34
1976
23
1977
18
1978
15
1979
21
1980
29
1981
18
1982
29
1983
6
1984
8
1985
24
1986
32
1987
20
1988
16
1989
17
1990
22
1991
19
1992
13
1993
11
1994
13
1995
16
1996
12
1997
14
1998
18
1999
18
2000
18
2001
26
2002
13
2003
22
2004
8
2005
10
2006
8
2007
16
2008
8
2009
6
2010
11
2011
25
2012
16
2013
15
2014
10
2015
16
2016
19
2017
31
2018
10
All-Time Record Progression
2 new records
2 all-time records were set at Castle Hot Springs between 2 February 1985 and 28 July 1995. Each dot is a new record.
When Castle Hot Springs set new all-time records
Date
Kind
Detail
1985-02-02
Record daily snowfall
Record daily snowfall 15.2 cm (6.0 in)
1995-07-28
Record high maximum temperature
Record high maximum temperature 48.9 C (120.0 F)
Wettest Day of Each Month
Sep: 101.6 mm (4.0 in)
The wettest day on record for each calendar month at Castle Hot Springs. The most was 101.6 mm (4.0 in) on 12 September 1966.
Record daily precipitation for each month at Castle Hot Springs
Month
Record daily precipitation (mm)
Date
Jan
90.2 mm (3.6 in)
21 January 2010
Feb
68.1 mm (2.7 in)
28 February 1978
Mar
85.1 mm (3.4 in)
1 March 1991
Apr
48.3 mm (1.9 in)
2 April 2004
May
37.1 mm (1.5 in)
20 May 1979
Jun
26.7 mm (1.1 in)
18 June 1967
Jul
52.1 mm (2.1 in)
28 July 1917
Aug
88.9 mm (3.5 in)
26 August 2003
Sep
101.6 mm (4.0 in)
12 September 1966
Oct
66.0 mm (2.6 in)
27 October 2000
Nov
57.2 mm (2.3 in)
23 November 1965
Dec
74.9 mm (2.9 in)
10 December 1965
Period of Record Coverage
1916 to 2018
Complete yearUnder 90 percent of days
72 years of record at Castle Hot Springs, 1916 to 2018. 14 years have data for under 90 percent of days and are left out of rankings: 1916, 1917, 1918, 1928, 1936, 1959, 1968, 1976 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 52 complete years at Castle Hot Springs, 1930 to 2017. Blue stripes are years cooler than the station's own mean of 21.3 C (70.3 F); red stripes are warmer. The coolest year was 1975, at 20.1 C (68.1 F), and the warmest was 2017, at 23.4 C (74.2 F). The strongest colour marks a difference of 2.2 C (4.0 F).
Annual mean temperature at Castle Hot Springs as warming stripes, 1930 to 2017
Year
Annual mean temperature
Difference from the station mean
1930
21.6 C
+0.29 C
1931
22.0 C
+0.74 C
1932
21.8 C
+0.47 C
1933
21.8 C
+0.53 C
1960
21.4 C
+0.10 C
1961
21.2 C
-0.04 C
1962
21.2 C
-0.05 C
1963
21.3 C
+0.06 C
1964
20.3 C
-0.98 C
1965
20.5 C
-0.74 C
1966
21.6 C
+0.28 C
1967
20.6 C
-0.69 C
1969
21.0 C
-0.24 C
1970
20.8 C
-0.48 C
1971
20.4 C
-0.92 C
1972
21.3 C
-0.01 C
1973
20.6 C
-0.71 C
1974
20.8 C
-0.52 C
1975
20.1 C
-1.21 C
1978
20.7 C
-0.61 C
1980
20.9 C
-0.39 C
1981
21.6 C
+0.30 C
1982
20.2 C
-1.13 C
1983
20.2 C
-1.12 C
1984
20.7 C
-0.62 C
1985
20.6 C
-0.65 C
1986
21.4 C
+0.12 C
1987
20.8 C
-0.46 C
1988
21.3 C
-0.01 C
1989
21.8 C
+0.52 C
1990
20.8 C
-0.53 C
1991
20.7 C
-0.62 C
1992
20.7 C
-0.54 C
1993
20.8 C
-0.51 C
1994
21.1 C
-0.22 C
1995
21.3 C
+0.04 C
2001
22.0 C
+0.69 C
2002
22.1 C
+0.84 C
2003
22.0 C
+0.76 C
2004
21.1 C
-0.15 C
2005
21.4 C
+0.10 C
2006
21.7 C
+0.40 C
2007
22.1 C
+0.83 C
2009
21.9 C
+0.63 C
2010
21.1 C
-0.21 C
2011
21.4 C
+0.10 C
2012
22.4 C
+1.08 C
2013
21.0 C
-0.25 C
2014
22.2 C
+0.96 C
2015
22.2 C
+0.96 C
2016
22.9 C
+1.63 C
2017
23.4 C
+2.14 C
The annual mean temperature here has risen by 0.10 C (0.01 to 0.18) per decade over 1930 to 2017. In Fahrenheit: 0.17 F (0.02 to 0.32) per decade. The slope is a straight line fitted to 52 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Castle Hot Springs
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.10 C (0.01 to 0.18) per decade
0.17 F (0.02 to 0.32) per decade
1930 to 2017
52
Rise
Mean daily maximum
0.2 C (0.1 to 0.3) per decade
0.3 F (0.1 to 0.5) per decade
1930 to 2017
52
Rise
Mean daily minimum
0.03 C (-0.09 to 0.14) per decade
0.05 F (-0.17 to 0.26) per decade
1930 to 2017
52
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
1916 to 2018
Yearly extremes at Castle Hot Springs: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
48.9 C (120.0 F)
1995
44.2 C (111.5 F)
72
Coldest night (TNn)
-8.3 C (17.1 F)
1963
-2.2 C (28.0 F)
73
Wettest day (Rx1day)
101.6 mm (4.0 in)
1966
49.4 mm (1.9 in)
72
Wettest five days (Rx5day)
222.8 mm (8.8 in)
1978
67.8 mm (2.7 in)
72
Longest dry spell (CDD)
170 days
2002
72 days
72
Hottest day (TXx)
The hottest day of the year at Castle Hot Springs, 1916 to 2018. The record is 48.9 C (120.0 F) in 1995, marked on the chart; the median year is 44.2 C (111.5 F).
Hottest day (TXx) at Castle Hot Springs by year
Year
Hottest day (TXx)
1916
44.4 C (111.9 F)
1917
43.9 C (111.0 F)
1918
32.8 C (91.0 F)
1919
n/a
1928
43.3 C (109.9 F)
1929
46.1 C (115.0 F)
1930
43.3 C (109.9 F)
1931
43.9 C (111.0 F)
1932
43.9 C (111.0 F)
1933
44.4 C (111.9 F)
1934
45.0 C (113.0 F)
1935
43.9 C (111.0 F)
1936
45.6 C (114.1 F)
1959
42.8 C (109.0 F)
1960
43.3 C (109.9 F)
1961
43.3 C (109.9 F)
1962
42.8 C (109.0 F)
1963
42.2 C (108.0 F)
1964
42.8 C (109.0 F)
1965
43.3 C (109.9 F)
1966
44.4 C (111.9 F)
1967
43.9 C (111.0 F)
1968
46.1 C (115.0 F)
1969
44.4 C (111.9 F)
1970
46.7 C (116.1 F)
1971
45.0 C (113.0 F)
1972
46.7 C (116.1 F)
1973
47.2 C (117.0 F)
1974
45.6 C (114.1 F)
1975
44.4 C (111.9 F)
1976
46.1 C (115.0 F)
1977
44.4 C (111.9 F)
1978
45.0 C (113.0 F)
1979
44.4 C (111.9 F)
1980
43.9 C (111.0 F)
1981
43.9 C (111.0 F)
1982
42.2 C (108.0 F)
1983
43.9 C (111.0 F)
1984
42.2 C (108.0 F)
1985
43.9 C (111.0 F)
1986
43.3 C (109.9 F)
1987
42.8 C (109.0 F)
1988
44.4 C (111.9 F)
1989
45.0 C (113.0 F)
1990
46.7 C (116.1 F)
1991
42.8 C (109.0 F)
1992
41.7 C (107.1 F)
1993
45.0 C (113.0 F)
1994
46.1 C (115.0 F)
1995
48.9 C (120.0 F)
1996
43.3 C (109.9 F)
1997
46.1 C (115.0 F)
1998
45.0 C (113.0 F)
1999
43.3 C (109.9 F)
2000
45.0 C (113.0 F)
2001
45.6 C (114.1 F)
2002
44.4 C (111.9 F)
2003
45.0 C (113.0 F)
2004
41.7 C (107.1 F)
2005
45.6 C (114.1 F)
2006
45.0 C (113.0 F)
2007
44.4 C (111.9 F)
2008
43.9 C (111.0 F)
2009
43.9 C (111.0 F)
2010
43.3 C (109.9 F)
2011
43.9 C (111.0 F)
2012
43.9 C (111.0 F)
2013
45.6 C (114.1 F)
2014
42.8 C (109.0 F)
2015
43.9 C (111.0 F)
2016
46.7 C (116.1 F)
2017
48.3 C (118.9 F)
2018
40.6 C (105.1 F)
Coldest night (TNn)
The coldest night of the year at Castle Hot Springs, 1916 to 2018. The record is -8.3 C (17.1 F) in 1963, marked on the chart; the median year is -2.2 C (28.0 F).
Coldest night (TNn) at Castle Hot Springs by year
Year
Coldest night (TNn)
1916
-3.3 C (26.1 F)
1917
0.6 C (33.1 F)
1918
-2.2 C (28.0 F)
1919
-0.6 C (30.9 F)
1928
1.1 C (34.0 F)
1929
-1.1 C (30.0 F)
1930
-2.2 C (28.0 F)
1931
-2.2 C (28.0 F)
1932
-1.1 C (30.0 F)
1933
-6.7 C (19.9 F)
1934
2.2 C (36.0 F)
1935
-2.8 C (27.0 F)
1936
9.4 C (48.9 F)
1959
0.0 C (32.0 F)
1960
-2.8 C (27.0 F)
1961
0.0 C (32.0 F)
1962
-3.3 C (26.1 F)
1963
-8.3 C (17.1 F)
1964
-2.8 C (27.0 F)
1965
-2.2 C (28.0 F)
1966
-3.3 C (26.1 F)
1967
-2.8 C (27.0 F)
1968
-5.6 C (21.9 F)
1969
-1.1 C (30.0 F)
1970
-2.8 C (27.0 F)
1971
-8.3 C (17.1 F)
1972
-2.2 C (28.0 F)
1973
-1.7 C (28.9 F)
1974
-3.9 C (25.0 F)
1975
-3.9 C (25.0 F)
1976
-5.6 C (21.9 F)
1977
-1.7 C (28.9 F)
1978
-4.4 C (24.1 F)
1979
-4.4 C (24.1 F)
1980
0.6 C (33.1 F)
1981
0.0 C (32.0 F)
1982
-2.2 C (28.0 F)
1983
-1.1 C (30.0 F)
1984
-2.2 C (28.0 F)
1985
-4.4 C (24.1 F)
1986
-1.7 C (28.9 F)
1987
-4.4 C (24.1 F)
1988
-3.3 C (26.1 F)
1989
-2.2 C (28.0 F)
1990
-5.0 C (23.0 F)
1991
-0.6 C (30.9 F)
1992
-1.7 C (28.9 F)
1993
-0.6 C (30.9 F)
1994
-1.7 C (28.9 F)
1995
-0.6 C (30.9 F)
1996
-0.6 C (30.9 F)
1997
-2.8 C (27.0 F)
1998
-2.8 C (27.0 F)
1999
-1.7 C (28.9 F)
2000
-1.1 C (30.0 F)
2001
-1.1 C (30.0 F)
2002
-3.9 C (25.0 F)
2003
-3.3 C (26.1 F)
2004
-1.7 C (28.9 F)
2005
-1.1 C (30.0 F)
2006
-2.2 C (28.0 F)
2007
-5.0 C (23.0 F)
2008
-2.8 C (27.0 F)
2009
0.6 C (33.1 F)
2010
-3.3 C (26.1 F)
2011
-5.6 C (21.9 F)
2012
-3.9 C (25.0 F)
2013
-5.0 C (23.0 F)
2014
0.0 C (32.0 F)
2015
-2.8 C (27.0 F)
2016
1.1 C (34.0 F)
2017
0.0 C (32.0 F)
2018
0.6 C (33.1 F)
Wettest day (Rx1day)
The wettest day of the year at Castle Hot Springs, 1916 to 2018. The record is 101.6 mm (4.0 in) in 1966, marked on the chart; the median year is 49.4 mm (1.9 in).
Wettest day (Rx1day) at Castle Hot Springs by year
Year
Wettest day (Rx1day)
1916
50.8 mm (2.0 in)
1917
52.1 mm (2.1 in)
1918
44.5 mm (1.8 in)
1919
n/a
1928
18.5 mm (0.7 in)
1929
32.0 mm (1.3 in)
1930
43.2 mm (1.7 in)
1931
41.9 mm (1.6 in)
1932
36.1 mm (1.4 in)
1933
36.8 mm (1.4 in)
1934
69.9 mm (2.8 in)
1935
50.8 mm (2.0 in)
1936
27.9 mm (1.1 in)
1959
46.0 mm (1.8 in)
1960
26.4 mm (1.0 in)
1961
46.5 mm (1.8 in)
1962
19.8 mm (0.8 in)
1963
68.6 mm (2.7 in)
1964
50.8 mm (2.0 in)
1965
74.9 mm (2.9 in)
1966
101.6 mm (4.0 in)
1967
64.8 mm (2.6 in)
1968
49.3 mm (1.9 in)
1969
33.8 mm (1.3 in)
1970
89.9 mm (3.5 in)
1971
18.3 mm (0.7 in)
1972
66.3 mm (2.6 in)
1973
26.7 mm (1.1 in)
1974
47.8 mm (1.9 in)
1975
25.4 mm (1.0 in)
1976
61.0 mm (2.4 in)
1977
32.0 mm (1.3 in)
1978
68.1 mm (2.7 in)
1979
37.1 mm (1.5 in)
1980
62.2 mm (2.4 in)
1981
41.1 mm (1.6 in)
1982
51.6 mm (2.0 in)
1983
79.0 mm (3.1 in)
1984
38.6 mm (1.5 in)
1985
50.8 mm (2.0 in)
1986
25.9 mm (1.0 in)
1987
27.2 mm (1.1 in)
1988
30.0 mm (1.2 in)
1989
48.5 mm (1.9 in)
1990
84.3 mm (3.3 in)
1991
85.1 mm (3.4 in)
1992
82.6 mm (3.3 in)
1993
53.3 mm (2.1 in)
1994
33.8 mm (1.3 in)
1995
57.7 mm (2.3 in)
1996
18.3 mm (0.7 in)
1997
10.2 mm (0.4 in)
1998
53.3 mm (2.1 in)
1999
27.9 mm (1.1 in)
2000
66.0 mm (2.6 in)
2001
21.6 mm (0.9 in)
2002
38.1 mm (1.5 in)
2003
88.9 mm (3.5 in)
2004
48.3 mm (1.9 in)
2005
59.7 mm (2.4 in)
2006
49.8 mm (2.0 in)
2007
57.2 mm (2.3 in)
2008
72.4 mm (2.9 in)
2009
68.6 mm (2.7 in)
2010
90.2 mm (3.6 in)
2011
38.1 mm (1.5 in)
2012
53.3 mm (2.1 in)
2013
40.6 mm (1.6 in)
2014
82.6 mm (3.3 in)
2015
49.5 mm (1.9 in)
2016
57.2 mm (2.3 in)
2017
63.5 mm (2.5 in)
2018
25.4 mm (1.0 in)
Wettest five days (Rx5day)
The wettest five days of the year at Castle Hot Springs, 1916 to 2018. The record is 222.8 mm (8.8 in) in 1978, marked on the chart; the median year is 67.8 mm (2.7 in).
Wettest five days (Rx5day) at Castle Hot Springs by year
Year
Wettest five days (Rx5day)
1916
119.4 mm (4.7 in)
1917
31.8 mm (1.3 in)
1918
66.1 mm (2.6 in)
1919
n/a
1928
38.3 mm (1.5 in)
1929
51.8 mm (2.0 in)
1930
58.5 mm (2.3 in)
1931
134.5 mm (5.3 in)
1932
68.0 mm (2.7 in)
1933
72.9 mm (2.9 in)
1934
69.9 mm (2.8 in)
1935
50.8 mm (2.0 in)
1936
48.3 mm (1.9 in)
1959
94.0 mm (3.7 in)
1960
43.2 mm (1.7 in)
1961
54.4 mm (2.1 in)
1962
41.1 mm (1.6 in)
1963
72.1 mm (2.8 in)
1964
66.8 mm (2.6 in)
1965
111.0 mm (4.4 in)
1966
165.8 mm (6.5 in)
1967
136.7 mm (5.4 in)
1968
59.5 mm (2.3 in)
1969
36.4 mm (1.4 in)
1970
115.8 mm (4.6 in)
1971
23.4 mm (0.9 in)
1972
118.9 mm (4.7 in)
1973
67.6 mm (2.7 in)
1974
61.0 mm (2.4 in)
1975
31.8 mm (1.3 in)
1976
113.8 mm (4.5 in)
1977
67.0 mm (2.6 in)
1978
222.8 mm (8.8 in)
1979
58.9 mm (2.3 in)
1980
127.4 mm (5.0 in)
1981
88.0 mm (3.5 in)
1982
63.5 mm (2.5 in)
1983
102.9 mm (4.1 in)
1984
68.3 mm (2.7 in)
1985
72.1 mm (2.8 in)
1986
60.2 mm (2.4 in)
1987
47.6 mm (1.9 in)
1988
57.4 mm (2.3 in)
1989
60.5 mm (2.4 in)
1990
91.2 mm (3.6 in)
1991
150.7 mm (5.9 in)
1992
95.3 mm (3.8 in)
1993
189.0 mm (7.4 in)
1994
41.5 mm (1.6 in)
1995
84.6 mm (3.3 in)
1996
20.8 mm (0.8 in)
1997
10.2 mm (0.4 in)
1998
68.6 mm (2.7 in)
1999
45.7 mm (1.8 in)
2000
85.0 mm (3.3 in)
2001
40.7 mm (1.6 in)
2002
52.1 mm (2.1 in)
2003
104.1 mm (4.1 in)
2004
64.8 mm (2.6 in)
2005
104.2 mm (4.1 in)
2006
49.8 mm (2.0 in)
2007
76.3 mm (3.0 in)
2008
85.1 mm (3.4 in)
2009
68.6 mm (2.7 in)
2010
146.1 mm (5.8 in)
2011
66.0 mm (2.6 in)
2012
69.9 mm (2.8 in)
2013
67.3 mm (2.6 in)
2014
82.6 mm (3.3 in)
2015
55.8 mm (2.2 in)
2016
72.5 mm (2.9 in)
2017
82.6 mm (3.3 in)
2018
25.4 mm (1.0 in)
Longest dry spell (CDD)
The longest dry spell of the year at Castle Hot Springs, 1916 to 2018. The record is 170 days in 2002, marked on the chart; the median year is 72 days.
Longest dry spell (CDD) at Castle Hot Springs by year
Year
Longest dry spell (CDD)
1916
78 days
1917
104 days
1918
49 days
1919
n/a
1928
49 days
1929
108 days
1930
44 days
1931
47 days
1932
61 days
1933
44 days
1934
41 days
1935
28 days
1936
61 days
1959
43 days
1960
134 days
1961
68 days
1962
56 days
1963
85 days
1964
110 days
1965
58 days
1966
92 days
1967
64 days
1968
58 days
1969
67 days
1970
70 days
1971
70 days
1972
157 days
1973
105 days
1974
118 days
1975
89 days
1976
48 days
1977
58 days
1978
69 days
1979
53 days
1980
55 days
1981
69 days
1982
55 days
1983
76 days
1984
49 days
1985
77 days
1986
59 days
1987
37 days
1988
57 days
1989
68 days
1990
49 days
1991
114 days
1992
37 days
1993
80 days
1994
52 days
1995
55 days
1996
108 days
1997
92 days
1998
106 days
1999
99 days
2000
104 days
2001
92 days
2002
170 days
2003
103 days
2004
95 days
2005
87 days
2006
74 days
2007
68 days
2008
90 days
2009
92 days
2010
128 days
2011
92 days
2012
96 days
2013
128 days
2014
123 days
2015
36 days
2016
74 days
2017
107 days
2018
81 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
30 years with a frost
Across 30 years with a frost, the median last spring frost at Castle Hot Springs falls on 12 February and the median first autumn frost on 12 December, which leaves a median of 304 days between them.
Fitted over all years, the growing season changes by +0.4 days per decade at this station.
Frost dates and growing season at Castle Hot Springs
Measure
Median, all years
Earliest period
Recent period (1931 to 2015)
Recent against earliest
Fitted trend
Last spring frost
12 February
n/a
12 February
n/a
-0.4 days per decade
First autumn frost
12 December
n/a
12 December
n/a
0.0 days per decade
Growing days
304 days
n/a
304 days
n/a
+0.4 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
58 years, 1929 to 2017
A day with at least 50.4 mm (2.0 in) of rain is expected about once in 2 years. A day with at least 110.1 mm (4.3 in) of rain is expected about once in 100 years.
Rainfall return levels at Castle Hot Springs: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
50.4 mm (2.0 in)
5 years
69.6 mm (2.7 in)
10 years
80.8 mm (3.2 in)
25 years
93.7 mm (3.7 in)
50 years
102.3 mm (4.0 in)
100 years
110.1 mm (4.3 in)
Longer than the 58 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, 58 years of values from 1929 to 2017.
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: 101.6 mm (4.0 in) in 1966; 90.2 mm (3.6 in) in 2010; 89.9 mm (3.5 in) in 1970.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Castle Hot Springs, at 1974. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1974 ran 0.3 C (0.5 F) lower than in the years before (likely change).
Suspected changes in the annual mean temperature at Castle Hot Springs, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1974
-0.3
-0.5
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.
Climate Twins
2002 to 2017 against 1961 to 1990
Over 2002 to 2017, Castle Hot Springs had a mean temperature of 21.9 C (71.5 F) and 334.5 mm (13.2 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are Altar (Obs) (Mexico, 367 km away), Ajo (United States, 185 km away) and Tucson WFO (United States, 235 km away).
Climate twins of Castle Hot Springs: stations whose 1961 to 1990 climate is closest to its 2002 to 2017 climate
Twins are stations, not cities. A twin is one of the three stations at least 100 km away whose earlier climate is closest to this station's recent one, so a close match does not mean the two places look alike in other ways. A station move or a gap in a record can change that station's averages. The list describes past climate; it is not a forecast and does not say what caused any change. How twins are found, and a search for any station.
Download the Data
Data for Castle Hot Springs standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Castle Hot Springs 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 2026-10-15 (15 October 2026). Records are computed by this site and are not official.