Record envelope, standing records and threshold days for Rocklin (USC00047516), California, United States, with 73 years of record.
Key Facts for Rocklin
Rocklin (USC00047516) is a weather station in California, United States at 38.80 latitude and -121.23 longitude, 76 m (249 ft) above sea level.
The station reports from 1904 to 1976, 73 years of record.
1,464 records set at Rocklin still stand.
Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
Rocklin set a daily record high minimum temperature of 18.9 C (66.0 F) on 13 May 1976.
About the Station
Location: California, United States, 38.80 latitude, -121.23 longitude.
Elevation: 76 m (249 ft).
Period of record: 1904 to 1976, 73 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 Rocklin. 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 Rocklin, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
24.4 C (75.9 F)
-10.0 C (14.0 F)
n/a
n/a
Feb
26.1 C (79.0 F)
-6.7 C (19.9 F)
n/a
n/a
Mar
32.2 C (90.0 F)
-5.0 C (23.0 F)
n/a
n/a
Apr
36.1 C (97.0 F)
-2.8 C (27.0 F)
n/a
n/a
May
41.7 C (107.1 F)
-1.1 C (30.0 F)
n/a
n/a
Jun
46.1 C (115.0 F)
1.1 C (34.0 F)
n/a
n/a
Jul
46.1 C (115.0 F)
1.1 C (34.0 F)
n/a
n/a
Aug
47.8 C (118.0 F)
0.6 C (33.1 F)
n/a
n/a
Sep
45.6 C (114.1 F)
-1.7 C (28.9 F)
n/a
n/a
Oct
40.6 C (105.1 F)
-3.9 C (25.0 F)
n/a
n/a
Nov
31.1 C (88.0 F)
-6.7 C (19.9 F)
n/a
n/a
Dec
26.7 C (80.1 F)
-10.0 C (14.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Rocklin still stand. 1922 holds the most, with 96.
Standing records at Rocklin by the year they were set
Year set
Standing records
1904
10
1905
14
1906
24
1907
20
1908
23
1909
18
1910
52
1911
49
1912
27
1913
35
1914
11
1915
11
1916
14
1917
32
1918
19
1919
18
1920
23
1921
44
1922
96
1923
21
1924
16
1925
25
1926
39
1927
61
1928
15
1929
25
1930
35
1931
29
1932
15
1933
25
1934
19
1935
8
1936
24
1937
19
1938
7
1939
18
1940
6
1941
11
1942
9
1943
10
1944
15
1945
13
1946
8
1947
12
1948
20
1949
16
1950
32
1951
20
1952
17
1953
14
1954
10
1955
22
1956
11
1957
13
1958
8
1959
7
1960
12
1961
22
1962
20
1963
20
1964
14
1965
19
1966
16
1967
20
1968
13
1969
9
1970
12
1971
17
1972
24
1973
12
1974
6
1975
10
1976
3
All-Time Record Progression
2 new records
2 all-time records were set at Rocklin between 22 January 1962 and 14 October 1962. Each dot is a new record.
When Rocklin set new all-time records
Date
Kind
Detail
1962-01-22
Record low maximum temperature
Record low maximum temperature -1.7 C (28.9 F)
1962-10-14
Record daily precipitation
Record daily precipitation 91.4 mm (3.6 in)
Wettest Day of Each Month
Oct: 91.4 mm (3.6 in)
The wettest day on record for each calendar month at Rocklin. The most was 91.4 mm (3.6 in) on 14 October 1962.
Record daily precipitation for each month at Rocklin
Month
Record daily precipitation (mm)
Date
Jan
63.5 mm (2.5 in)
14 January 1911
Feb
78.7 mm (3.1 in)
10 February 1962
Mar
72.9 mm (2.9 in)
22 March 1937
Apr
90.2 mm (3.6 in)
8 April 1935
May
38.1 mm (1.5 in)
28 May 1906
Jun
36.8 mm (1.4 in)
16 June 1931
Jul
27.9 mm (1.1 in)
9 July 1974
Aug
14.0 mm (0.6 in)
12 August 1965
Sep
54.6 mm (2.1 in)
13 September 1918
Oct
91.4 mm (3.6 in)
14 October 1962
Nov
53.3 mm (2.1 in)
20 November 1966
Dec
65.3 mm (2.6 in)
11 December 1937
Period of Record Coverage
1904 to 1976
Complete yearUnder 90 percent of days
73 years of record at Rocklin, 1904 to 1976. 5 years have data for under 90 percent of days and are left out of rankings: 1904, 1928, 1929, 1932, 1976.
Cooler than the station meanWarmer than the station mean
One stripe for each of 63 complete years at Rocklin, 1905 to 1975. Blue stripes are years cooler than the station's own mean of 15.6 C (60.0 F); red stripes are warmer. The coolest year was 1922, at 14.0 C (57.3 F), and the warmest was 1910, at 17.0 C (62.5 F). The strongest colour marks a difference of 1.6 C (2.9 F).
Annual mean temperature at Rocklin as warming stripes, 1905 to 1975
Year
Annual mean temperature
Difference from the station mean
1905
15.9 C
+0.31 C
1906
16.4 C
+0.83 C
1907
15.9 C
+0.32 C
1908
15.9 C
+0.28 C
1909
15.9 C
+0.31 C
1910
17.0 C
+1.38 C
1911
16.6 C
+1.03 C
1912
16.0 C
+0.46 C
1913
15.9 C
+0.30 C
1914
15.8 C
+0.18 C
1915
15.4 C
-0.20 C
1917
14.4 C
-1.22 C
1918
15.6 C
+0.02 C
1919
15.8 C
+0.21 C
1920
14.7 C
-0.91 C
1921
15.9 C
+0.33 C
1922
14.0 C
-1.54 C
1923
15.1 C
-0.50 C
1924
15.8 C
+0.20 C
1925
15.7 C
+0.13 C
1926
16.5 C
+0.93 C
1927
14.9 C
-0.73 C
1931
16.6 C
+1.01 C
1933
16.2 C
+0.61 C
1935
15.5 C
-0.13 C
1936
16.6 C
+0.99 C
1937
15.5 C
-0.10 C
1938
15.5 C
-0.04 C
1939
16.4 C
+0.79 C
1940
16.4 C
+0.81 C
1941
15.7 C
+0.07 C
1942
14.9 C
-0.64 C
1943
15.5 C
-0.05 C
1944
15.0 C
-0.61 C
1945
15.6 C
+0.04 C
1946
15.2 C
-0.37 C
1947
15.8 C
+0.23 C
1948
14.7 C
-0.85 C
1949
15.5 C
-0.05 C
1950
16.1 C
+0.54 C
1951
15.5 C
-0.06 C
1952
15.5 C
-0.05 C
1953
15.4 C
-0.16 C
1954
15.0 C
-0.58 C
1955
15.0 C
-0.60 C
1956
15.0 C
-0.54 C
1957
15.4 C
-0.22 C
1958
16.5 C
+0.90 C
1959
16.1 C
+0.51 C
1960
15.6 C
-0.03 C
1961
14.9 C
-0.70 C
1962
14.6 C
-0.96 C
1964
15.0 C
-0.55 C
1965
14.5 C
-1.04 C
1966
15.3 C
-0.24 C
1968
15.8 C
+0.24 C
1969
16.1 C
+0.49 C
1970
16.1 C
+0.47 C
1971
15.1 C
-0.47 C
1972
15.3 C
-0.27 C
1973
15.9 C
+0.33 C
1974
15.4 C
-0.18 C
1975
15.1 C
-0.49 C
The annual mean temperature here has fallen by 0.08 C (0.01 to 0.15) per decade over 1905 to 1975. In Fahrenheit: 0.14 F (0.01 to 0.26) per decade. The slope is a straight line fitted to 63 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Rocklin
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
-0.08 C (-0.15 to 0.00) per decade
-0.14 F (-0.26 to -0.01) per decade
1905 to 1975
63
Fall
Mean daily maximum
-0.02 C (-0.09 to 0.06) per decade
-0.03 F (-0.16 to 0.10) per decade
1905 to 1975
63
Not clearly different from zero
Mean daily minimum
-0.14 C (-0.24 to -0.04) per decade
-0.2 F (-0.4 to -0.1) per decade
1905 to 1975
63
Fall
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
1904 to 1976
Yearly extremes at Rocklin: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
47.8 C (118.0 F)
1933
42.8 C (109.0 F)
73
Coldest night (TNn)
-10.0 C (14.0 F)
1932
-5.6 C (21.9 F)
73
Wettest day (Rx1day)
91.4 mm (3.6 in)
1962
47.5 mm (1.9 in)
73
Wettest five days (Rx5day)
241.3 mm (9.5 in)
1962
92.8 mm (3.7 in)
73
Longest dry spell (CDD)
179 days
1966
109 days
73
Hottest day (TXx)
The hottest day of the year at Rocklin, 1904 to 1976. The record is 47.8 C (118.0 F) in 1933, marked on the chart; the median year is 42.8 C (109.0 F).
Hottest day (TXx) at Rocklin by year
Year
Hottest day (TXx)
1904
40.6 C (105.1 F)
1905
45.6 C (114.1 F)
1906
41.7 C (107.1 F)
1907
37.8 C (100.0 F)
1908
43.3 C (109.9 F)
1909
40.6 C (105.1 F)
1910
41.7 C (107.1 F)
1911
42.8 C (109.0 F)
1912
40.6 C (105.1 F)
1913
43.9 C (111.0 F)
1914
41.1 C (106.0 F)
1915
42.2 C (108.0 F)
1916
42.2 C (108.0 F)
1917
42.2 C (108.0 F)
1918
43.3 C (109.9 F)
1919
42.2 C (108.0 F)
1920
43.3 C (109.9 F)
1921
43.9 C (111.0 F)
1922
44.4 C (111.9 F)
1923
44.4 C (111.9 F)
1924
41.7 C (107.1 F)
1925
45.0 C (113.0 F)
1926
43.3 C (109.9 F)
1927
41.7 C (107.1 F)
1928
41.7 C (107.1 F)
1929
42.8 C (109.0 F)
1930
42.2 C (108.0 F)
1931
43.9 C (111.0 F)
1932
41.7 C (107.1 F)
1933
47.8 C (118.0 F)
1934
43.3 C (109.9 F)
1935
43.9 C (111.0 F)
1936
45.6 C (114.1 F)
1937
43.9 C (111.0 F)
1938
44.4 C (111.9 F)
1939
43.3 C (109.9 F)
1940
42.2 C (108.0 F)
1941
43.9 C (111.0 F)
1942
45.0 C (113.0 F)
1943
42.8 C (109.0 F)
1944
42.2 C (108.0 F)
1945
42.8 C (109.0 F)
1946
42.2 C (108.0 F)
1947
42.8 C (109.0 F)
1948
43.9 C (111.0 F)
1949
42.8 C (109.0 F)
1950
45.6 C (114.1 F)
1951
43.3 C (109.9 F)
1952
42.8 C (109.0 F)
1953
42.8 C (109.0 F)
1954
43.3 C (109.9 F)
1955
43.9 C (111.0 F)
1956
43.3 C (109.9 F)
1957
43.3 C (109.9 F)
1958
42.2 C (108.0 F)
1959
44.4 C (111.9 F)
1960
45.0 C (113.0 F)
1961
46.1 C (115.0 F)
1962
41.1 C (106.0 F)
1963
41.1 C (106.0 F)
1964
41.7 C (107.1 F)
1965
40.0 C (104.0 F)
1966
42.8 C (109.0 F)
1967
42.8 C (109.0 F)
1968
42.2 C (108.0 F)
1969
42.2 C (108.0 F)
1970
43.3 C (109.9 F)
1971
45.0 C (113.0 F)
1972
45.6 C (114.1 F)
1973
42.8 C (109.0 F)
1974
41.1 C (106.0 F)
1975
44.4 C (111.9 F)
1976
41.1 C (106.0 F)
Coldest night (TNn)
The coldest night of the year at Rocklin, 1904 to 1976. The record is -10.0 C (14.0 F) in 1932, marked on the chart; the median year is -5.6 C (21.9 F).
Coldest night (TNn) at Rocklin by year
Year
Coldest night (TNn)
1904
-2.2 C (28.0 F)
1905
-4.4 C (24.1 F)
1906
-5.6 C (21.9 F)
1907
-2.8 C (27.0 F)
1908
-4.4 C (24.1 F)
1909
-3.9 C (25.0 F)
1910
-4.4 C (24.1 F)
1911
-2.8 C (27.0 F)
1912
-5.0 C (23.0 F)
1913
-6.7 C (19.9 F)
1914
-3.9 C (25.0 F)
1915
-3.3 C (26.1 F)
1916
-5.6 C (21.9 F)
1917
-8.3 C (17.1 F)
1918
-4.4 C (24.1 F)
1919
-7.2 C (19.0 F)
1920
-6.1 C (21.0 F)
1921
-6.7 C (19.9 F)
1922
-7.2 C (19.0 F)
1923
-5.0 C (23.0 F)
1924
-6.1 C (21.0 F)
1925
-3.9 C (25.0 F)
1926
-5.0 C (23.0 F)
1927
-5.0 C (23.0 F)
1928
-6.7 C (19.9 F)
1929
-6.7 C (19.9 F)
1930
-7.2 C (19.0 F)
1931
-6.7 C (19.9 F)
1932
-10.0 C (14.0 F)
1933
-5.6 C (21.9 F)
1934
-2.2 C (28.0 F)
1935
-4.4 C (24.1 F)
1936
-6.1 C (21.0 F)
1937
-10.0 C (14.0 F)
1938
-3.9 C (25.0 F)
1939
-3.9 C (25.0 F)
1940
-7.8 C (18.0 F)
1941
-3.3 C (26.1 F)
1942
-5.6 C (21.9 F)
1943
-6.1 C (21.0 F)
1944
-5.0 C (23.0 F)
1945
-4.4 C (24.1 F)
1946
-4.4 C (24.1 F)
1947
-3.9 C (25.0 F)
1948
-5.6 C (21.9 F)
1949
-8.3 C (17.1 F)
1950
-6.1 C (21.0 F)
1951
-5.0 C (23.0 F)
1952
-5.6 C (21.9 F)
1953
-3.3 C (26.1 F)
1954
-3.3 C (26.1 F)
1955
-4.4 C (24.1 F)
1956
-5.6 C (21.9 F)
1957
-6.7 C (19.9 F)
1958
-4.4 C (24.1 F)
1959
-5.6 C (21.9 F)
1960
-8.9 C (16.0 F)
1961
-7.2 C (19.0 F)
1962
-6.7 C (19.9 F)
1963
-7.2 C (19.0 F)
1964
-3.9 C (25.0 F)
1965
-7.2 C (19.0 F)
1966
-7.2 C (19.0 F)
1967
-6.7 C (19.9 F)
1968
-5.6 C (21.9 F)
1969
-3.9 C (25.0 F)
1970
-4.4 C (24.1 F)
1971
-6.7 C (19.9 F)
1972
-9.4 C (15.1 F)
1973
-5.6 C (21.9 F)
1974
-5.0 C (23.0 F)
1975
-6.7 C (19.9 F)
1976
-4.4 C (24.1 F)
Wettest day (Rx1day)
The wettest day of the year at Rocklin, 1904 to 1976. The record is 91.4 mm (3.6 in) in 1962, marked on the chart; the median year is 47.5 mm (1.9 in).
Wettest day (Rx1day) at Rocklin by year
Year
Wettest day (Rx1day)
1904
36.8 mm (1.4 in)
1905
33.8 mm (1.3 in)
1906
50.8 mm (2.0 in)
1907
55.9 mm (2.2 in)
1908
46.2 mm (1.8 in)
1909
57.2 mm (2.3 in)
1910
38.4 mm (1.5 in)
1911
63.5 mm (2.5 in)
1912
25.4 mm (1.0 in)
1913
36.8 mm (1.4 in)
1914
51.3 mm (2.0 in)
1915
35.6 mm (1.4 in)
1916
50.8 mm (2.0 in)
1917
38.1 mm (1.5 in)
1918
54.6 mm (2.1 in)
1919
39.4 mm (1.6 in)
1920
34.3 mm (1.4 in)
1921
51.6 mm (2.0 in)
1922
50.8 mm (2.0 in)
1923
38.6 mm (1.5 in)
1924
47.5 mm (1.9 in)
1925
40.6 mm (1.6 in)
1926
45.0 mm (1.8 in)
1927
33.8 mm (1.3 in)
1928
35.3 mm (1.4 in)
1929
53.3 mm (2.1 in)
1930
33.5 mm (1.3 in)
1931
44.7 mm (1.8 in)
1932
29.5 mm (1.2 in)
1933
39.6 mm (1.6 in)
1934
34.3 mm (1.4 in)
1935
90.2 mm (3.6 in)
1936
55.4 mm (2.2 in)
1937
72.9 mm (2.9 in)
1938
36.6 mm (1.4 in)
1939
61.2 mm (2.4 in)
1940
63.0 mm (2.5 in)
1941
47.0 mm (1.9 in)
1942
40.9 mm (1.6 in)
1943
52.1 mm (2.1 in)
1944
62.2 mm (2.4 in)
1945
45.7 mm (1.8 in)
1946
40.6 mm (1.6 in)
1947
38.1 mm (1.5 in)
1948
41.9 mm (1.6 in)
1949
49.8 mm (2.0 in)
1950
50.8 mm (2.0 in)
1951
33.0 mm (1.3 in)
1952
62.2 mm (2.4 in)
1953
34.0 mm (1.3 in)
1954
53.3 mm (2.1 in)
1955
48.8 mm (1.9 in)
1956
38.1 mm (1.5 in)
1957
30.5 mm (1.2 in)
1958
54.6 mm (2.1 in)
1959
50.8 mm (2.0 in)
1960
40.6 mm (1.6 in)
1961
41.9 mm (1.6 in)
1962
91.4 mm (3.6 in)
1963
50.8 mm (2.0 in)
1964
55.9 mm (2.2 in)
1965
48.3 mm (1.9 in)
1966
53.3 mm (2.1 in)
1967
58.4 mm (2.3 in)
1968
52.1 mm (2.1 in)
1969
51.6 mm (2.0 in)
1970
51.6 mm (2.0 in)
1971
52.1 mm (2.1 in)
1972
33.0 mm (1.3 in)
1973
48.3 mm (1.9 in)
1974
40.6 mm (1.6 in)
1975
49.8 mm (2.0 in)
1976
24.1 mm (0.9 in)
Wettest five days (Rx5day)
The wettest five days of the year at Rocklin, 1904 to 1976. The record is 241.3 mm (9.5 in) in 1962, marked on the chart; the median year is 92.8 mm (3.7 in).
Wettest five days (Rx5day) at Rocklin by year
Year
Wettest five days (Rx5day)
1904
87.0 mm (3.4 in)
1905
58.0 mm (2.3 in)
1906
186.3 mm (7.3 in)
1907
132.2 mm (5.2 in)
1908
88.2 mm (3.5 in)
1909
155.2 mm (6.1 in)
1910
66.3 mm (2.6 in)
1911
194.3 mm (7.6 in)
1912
45.8 mm (1.8 in)
1913
88.9 mm (3.5 in)
1914
126.2 mm (5.0 in)
1915
73.7 mm (2.9 in)
1916
88.9 mm (3.5 in)
1917
87.6 mm (3.4 in)
1918
76.5 mm (3.0 in)
1919
88.5 mm (3.5 in)
1920
62.9 mm (2.5 in)
1921
90.4 mm (3.6 in)
1922
128.5 mm (5.1 in)
1923
96.3 mm (3.8 in)
1924
78.0 mm (3.1 in)
1925
108.9 mm (4.3 in)
1926
127.5 mm (5.0 in)
1927
91.9 mm (3.6 in)
1928
93.5 mm (3.7 in)
1929
101.0 mm (4.0 in)
1930
75.2 mm (3.0 in)
1931
136.0 mm (5.4 in)
1932
70.6 mm (2.8 in)
1933
85.0 mm (3.3 in)
1934
98.8 mm (3.9 in)
1935
110.9 mm (4.4 in)
1936
135.1 mm (5.3 in)
1937
125.8 mm (5.0 in)
1938
120.4 mm (4.7 in)
1939
95.5 mm (3.8 in)
1940
150.4 mm (5.9 in)
1941
87.6 mm (3.4 in)
1942
101.5 mm (4.0 in)
1943
135.1 mm (5.3 in)
1944
77.7 mm (3.1 in)
1945
127.8 mm (5.0 in)
1946
83.8 mm (3.3 in)
1947
65.0 mm (2.6 in)
1948
46.5 mm (1.8 in)
1949
70.2 mm (2.8 in)
1950
155.5 mm (6.1 in)
1951
92.8 mm (3.7 in)
1952
179.8 mm (7.1 in)
1953
54.1 mm (2.1 in)
1954
78.7 mm (3.1 in)
1955
128.3 mm (5.1 in)
1956
87.7 mm (3.5 in)
1957
70.4 mm (2.8 in)
1958
130.6 mm (5.1 in)
1959
90.1 mm (3.5 in)
1960
71.7 mm (2.8 in)
1961
95.2 mm (3.7 in)
1962
241.3 mm (9.5 in)
1963
110.5 mm (4.4 in)
1964
156.3 mm (6.2 in)
1965
92.3 mm (3.6 in)
1966
93.7 mm (3.7 in)
1967
136.4 mm (5.4 in)
1968
67.3 mm (2.6 in)
1969
134.7 mm (5.3 in)
1970
129.4 mm (5.1 in)
1971
95.0 mm (3.7 in)
1972
61.8 mm (2.4 in)
1973
118.6 mm (4.7 in)
1974
56.1 mm (2.2 in)
1975
84.7 mm (3.3 in)
1976
40.1 mm (1.6 in)
Longest dry spell (CDD)
The longest dry spell of the year at Rocklin, 1904 to 1976. The record is 179 days in 1966, marked on the chart; the median year is 109 days.
Longest dry spell (CDD) at Rocklin by year
Year
Longest dry spell (CDD)
1904
22 days
1905
110 days
1906
63 days
1907
133 days
1908
106 days
1909
102 days
1910
133 days
1911
69 days
1912
70 days
1913
157 days
1914
41 days
1915
39 days
1916
69 days
1917
75 days
1918
20 days
1919
15 days
1920
19 days
1921
21 days
1922
20 days
1923
46 days
1924
31 days
1925
31 days
1926
147 days
1927
140 days
1928
140 days
1929
111 days
1930
109 days
1931
126 days
1932
96 days
1933
137 days
1934
109 days
1935
124 days
1936
145 days
1937
119 days
1938
121 days
1939
111 days
1940
104 days
1941
103 days
1942
105 days
1943
128 days
1944
105 days
1945
125 days
1946
112 days
1947
121 days
1948
132 days
1949
172 days
1950
97 days
1951
143 days
1952
73 days
1953
126 days
1954
77 days
1955
129 days
1956
111 days
1957
129 days
1958
101 days
1959
143 days
1960
101 days
1961
133 days
1962
84 days
1963
124 days
1964
141 days
1965
112 days
1966
179 days
1967
96 days
1968
72 days
1969
119 days
1970
128 days
1971
94 days
1972
107 days
1973
154 days
1974
110 days
1975
59 days
1976
51 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
62 years with a frost
Across 62 years with a frost, the median last spring frost at Rocklin falls on 26 March and the median first autumn frost on 11 November, which leaves a median of 227 days between them.
In 1943 to 1975 the median growing season was 224 days. That is 15 days fewer than in 1905 to 1940.
Fitted over all years, the growing season changes by -4.6 days per decade at this station.
Frost dates and growing season at Rocklin
Measure
Median, all years
Earliest period (1905 to 1940)
Recent period (1943 to 1975)
Recent against earliest
Fitted trend
Last spring frost
26 March
15 March
28 March
13 days later
+3.7 days per decade
First autumn frost
11 November
11 November
6 November
5 days earlier
-0.9 days per decade
Growing days
227 days
239 days
224 days
15 days fewer
-4.6 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
55 years, 1906 to 1975
A day with at least 46.7 mm (1.8 in) of rain is expected about once in 2 years. A day with at least 85.9 mm (3.4 in) of rain is expected about once in 100 years.
Rainfall return levels at Rocklin: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
46.7 mm (1.8 in)
5 years
57.9 mm (2.3 in)
10 years
65.1 mm (2.6 in)
25 years
73.8 mm (2.9 in)
50 years
80.0 mm (3.1 in)
100 years
85.9 mm (3.4 in)
Longer than the 55 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, 55 years of values from 1906 to 1975.
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: 91.4 mm (3.6 in) in 1962; 90.2 mm (3.6 in) in 1935; 72.9 mm (2.9 in) in 1937.
Station Changes
No change in the annual mean temperature of this station was found against its neighbours.
Download the Data
Data for Rocklin standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Rocklin 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.