Record envelope, standing records and threshold days for Folsom (USC00043111), California, United States, with 63 years of record.
Key Facts for Folsom
Folsom (USC00043111) is a weather station in California, United States at 38.68 latitude and -121.18 longitude, 76 m (249 ft) above sea level.
The station reports from 1893 to 1955, 63 years of record.
1,464 records set at Folsom still stand.
Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
Folsom set a daily record high maximum temperature of 31.1 C (88.0 F) on 30 October 1955.
About the Station
Location: California, United States, 38.68 latitude, -121.18 longitude.
Elevation: 76 m (249 ft).
Period of record: 1893 to 1955, 63 years.
Eligible elements: tmax, tmin, prcp.
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 Folsom. 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 Folsom, 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)
-9.4 C (15.1 F)
n/a
n/a
Feb
25.6 C (78.1 F)
-5.0 C (23.0 F)
n/a
n/a
Mar
31.1 C (88.0 F)
-3.3 C (26.1 F)
n/a
n/a
Apr
36.7 C (98.1 F)
-1.1 C (30.0 F)
n/a
n/a
May
43.9 C (111.0 F)
2.2 C (36.0 F)
n/a
n/a
Jun
46.1 C (115.0 F)
3.9 C (39.0 F)
n/a
n/a
Jul
48.3 C (118.9 F)
8.3 C (46.9 F)
n/a
n/a
Aug
46.1 C (115.0 F)
3.9 C (39.0 F)
n/a
n/a
Sep
45.6 C (114.1 F)
3.9 C (39.0 F)
n/a
n/a
Oct
38.9 C (102.0 F)
-1.1 C (30.0 F)
n/a
n/a
Nov
33.9 C (93.0 F)
-4.4 C (24.1 F)
n/a
n/a
Dec
23.9 C (75.0 F)
-8.3 C (17.1 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Folsom still stand. 1918 holds the most, with 54.
Standing records at Folsom by the year they were set
Year set
Standing records
1904
10
1905
35
1906
41
1907
23
1908
29
1909
24
1910
27
1911
22
1912
25
1913
48
1914
39
1915
26
1916
34
1917
34
1918
54
1919
28
1920
39
1921
46
1922
49
1923
25
1924
36
1925
28
1926
26
1927
33
1928
28
1929
38
1930
22
1931
23
1932
30
1933
32
1934
22
1935
19
1936
21
1937
18
1938
22
1939
30
1940
27
1941
30
1942
27
1943
22
1944
22
1945
16
1946
21
1947
18
1948
29
1949
27
1950
35
1951
18
1952
24
1953
21
1954
19
1955
22
All-Time Record Progression
1 new records
1 all-time records were set at Folsom between 21 January 1937 and 21 January 1937. Each dot is a new record.
When Folsom set new all-time records
Date
Kind
Detail
1937-01-21
Record low minimum temperature
Record low minimum temperature -9.4 C (15.1 F)
Wettest Day of Each Month
Dec: 96.3 mm (3.8 in)
The wettest day on record for each calendar month at Folsom. The most was 96.3 mm (3.8 in) on 11 December 1906.
Record daily precipitation for each month at Folsom
Month
Record daily precipitation (mm)
Date
Jan
86.6 mm (3.4 in)
4 January 1895
Feb
73.9 mm (2.9 in)
20 February 1894
Mar
74.2 mm (2.9 in)
30 March 1903
Apr
67.8 mm (2.7 in)
29 April 1901
May
44.2 mm (1.7 in)
30 May 1945
Jun
31.0 mm (1.2 in)
16 June 1929
Jul
7.6 mm (0.30 in)
2 July 1916
Aug
12.4 mm (0.5 in)
31 August 1896
Sep
58.4 mm (2.3 in)
13 September 1918
Oct
66.5 mm (2.6 in)
27 October 1901
Nov
62.2 mm (2.4 in)
7 November 1922
Dec
96.3 mm (3.8 in)
11 December 1906
Period of Record Coverage
1904 to 1955
Complete yearUnder 90 percent of days
52 years of record at Folsom, 1904 to 1955. 4 years have data for under 90 percent of days and are left out of rankings: 1904, 1911, 1914, 1955.
Cooler than the station meanWarmer than the station mean
One stripe for each of 45 complete years at Folsom, 1905 to 1954. Blue stripes are years cooler than the station's own mean of 16.3 C (61.4 F); red stripes are warmer. The coolest year was 1948, at 14.9 C (58.9 F), and the warmest was 1915, at 17.4 C (63.4 F). The strongest colour marks a difference of 1.5 C (2.7 F).
Annual mean temperature at Folsom as warming stripes, 1905 to 1954
Year
Annual mean temperature
Difference from the station mean
1905
16.9 C
+0.53 C
1906
17.1 C
+0.75 C
1908
17.0 C
+0.65 C
1909
16.7 C
+0.32 C
1910
16.8 C
+0.42 C
1912
15.5 C
-0.85 C
1915
17.4 C
+1.08 C
1916
16.5 C
+0.18 C
1917
17.2 C
+0.87 C
1918
17.3 C
+0.98 C
1920
16.4 C
+0.04 C
1921
17.0 C
+0.63 C
1922
15.4 C
-0.93 C
1923
15.9 C
-0.45 C
1924
16.3 C
+0.00 C
1925
16.2 C
-0.10 C
1926
17.2 C
+0.81 C
1927
15.9 C
-0.44 C
1928
16.4 C
+0.03 C
1929
16.1 C
-0.21 C
1930
16.2 C
-0.19 C
1931
17.1 C
+0.75 C
1932
16.3 C
+0.00 C
1933
15.9 C
-0.41 C
1934
17.4 C
+1.03 C
1935
16.0 C
-0.34 C
1936
17.0 C
+0.69 C
1937
16.3 C
-0.07 C
1938
16.2 C
-0.14 C
1939
17.0 C
+0.61 C
1940
17.1 C
+0.73 C
1941
16.0 C
-0.39 C
1942
15.3 C
-1.01 C
1943
16.3 C
-0.04 C
1944
15.8 C
-0.53 C
1945
15.9 C
-0.44 C
1946
15.3 C
-1.00 C
1947
16.0 C
-0.34 C
1948
14.9 C
-1.42 C
1949
15.6 C
-0.73 C
1950
16.6 C
+0.25 C
1951
16.0 C
-0.30 C
1952
16.1 C
-0.21 C
1953
16.1 C
-0.20 C
1954
15.7 C
-0.62 C
The annual mean temperature here has fallen by 0.2 C (0.1 to 0.3) per decade over 1905 to 1954. In Fahrenheit: 0.4 F (0.2 to 0.6) per decade. The slope is a straight line fitted to 45 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Folsom
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
-0.2 C (-0.3 to -0.1) per decade
-0.4 F (-0.6 to -0.2) per decade
1905 to 1954
45
Fall
Mean daily maximum
-0.19 C (-0.33 to -0.04) per decade
-0.3 F (-0.6 to -0.1) per decade
1905 to 1954
45
Fall
Mean daily minimum
-0.2 C (-0.4 to -0.1) per decade
-0.4 F (-0.7 to -0.1) per decade
1905 to 1954
45
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
1893 to 1955
Yearly extremes at Folsom: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
48.3 C (118.9 F)
1905
43.3 C (109.9 F)
52
Coldest night (TNn)
-9.4 C (15.1 F)
1937
-3.9 C (25.0 F)
52
Wettest day (Rx1day)
96.3 mm (3.8 in)
1906
50.3 mm (2.0 in)
63
Wettest five days (Rx5day)
223.5 mm (8.8 in)
1911
99.3 mm (3.9 in)
63
Longest dry spell (CDD)
157 days
1932
105 days
63
Hottest day (TXx)
The hottest day of the year at Folsom, 1893 to 1955. The record is 48.3 C (118.9 F) in 1905, marked on the chart; the median year is 43.3 C (109.9 F).
Hottest day (TXx) at Folsom by year
Year
Hottest day (TXx)
1893
n/a
1894
n/a
1895
n/a
1896
n/a
1897
n/a
1898
n/a
1899
n/a
1900
n/a
1901
n/a
1902
n/a
1903
n/a
1904
43.3 C (109.9 F)
1905
48.3 C (118.9 F)
1906
44.4 C (111.9 F)
1907
40.0 C (104.0 F)
1908
45.0 C (113.0 F)
1909
42.2 C (108.0 F)
1910
43.9 C (111.0 F)
1911
42.2 C (108.0 F)
1912
41.1 C (106.0 F)
1913
43.9 C (111.0 F)
1914
41.7 C (107.1 F)
1915
42.8 C (109.0 F)
1916
42.2 C (108.0 F)
1917
43.9 C (111.0 F)
1918
43.3 C (109.9 F)
1919
42.8 C (109.0 F)
1920
43.3 C (109.9 F)
1921
42.2 C (108.0 F)
1922
45.6 C (114.1 F)
1923
44.4 C (111.9 F)
1924
42.2 C (108.0 F)
1925
46.1 C (115.0 F)
1926
44.4 C (111.9 F)
1927
42.2 C (108.0 F)
1928
41.7 C (107.1 F)
1929
44.4 C (111.9 F)
1930
42.2 C (108.0 F)
1931
45.0 C (113.0 F)
1932
42.8 C (109.0 F)
1933
44.4 C (111.9 F)
1934
43.9 C (111.0 F)
1935
43.3 C (109.9 F)
1936
43.3 C (109.9 F)
1937
43.9 C (111.0 F)
1938
43.9 C (111.0 F)
1939
43.3 C (109.9 F)
1940
42.2 C (108.0 F)
1941
43.3 C (109.9 F)
1942
45.0 C (113.0 F)
1943
43.3 C (109.9 F)
1944
42.8 C (109.0 F)
1945
43.9 C (111.0 F)
1946
43.9 C (111.0 F)
1947
41.7 C (107.1 F)
1948
42.8 C (109.0 F)
1949
41.1 C (106.0 F)
1950
44.4 C (111.9 F)
1951
42.8 C (109.0 F)
1952
40.6 C (105.1 F)
1953
41.7 C (107.1 F)
1954
43.3 C (109.9 F)
1955
42.8 C (109.0 F)
Coldest night (TNn)
The coldest night of the year at Folsom, 1893 to 1955. The record is -9.4 C (15.1 F) in 1937, marked on the chart; the median year is -3.9 C (25.0 F).
Coldest night (TNn) at Folsom by year
Year
Coldest night (TNn)
1893
n/a
1894
n/a
1895
n/a
1896
n/a
1897
n/a
1898
n/a
1899
n/a
1900
n/a
1901
n/a
1902
n/a
1903
n/a
1904
-2.2 C (28.0 F)
1905
-3.9 C (25.0 F)
1906
-4.4 C (24.1 F)
1907
-2.2 C (28.0 F)
1908
-2.8 C (27.0 F)
1909
-2.2 C (28.0 F)
1910
-4.4 C (24.1 F)
1911
-3.9 C (25.0 F)
1912
-3.3 C (26.1 F)
1913
-4.4 C (24.1 F)
1914
-1.1 C (30.0 F)
1915
-4.4 C (24.1 F)
1916
-2.2 C (28.0 F)
1917
-5.0 C (23.0 F)
1918
-4.4 C (24.1 F)
1919
-3.9 C (25.0 F)
1920
-1.1 C (30.0 F)
1921
-2.2 C (28.0 F)
1922
-5.0 C (23.0 F)
1923
-3.3 C (26.1 F)
1924
-5.6 C (21.9 F)
1925
-2.2 C (28.0 F)
1926
-2.8 C (27.0 F)
1927
-2.8 C (27.0 F)
1928
-5.6 C (21.9 F)
1929
-4.4 C (24.1 F)
1930
-5.0 C (23.0 F)
1931
-2.8 C (27.0 F)
1932
-8.3 C (17.1 F)
1933
-4.4 C (24.1 F)
1934
0.0 C (32.0 F)
1935
-3.3 C (26.1 F)
1936
-2.8 C (27.0 F)
1937
-9.4 C (15.1 F)
1938
-1.7 C (28.9 F)
1939
-3.3 C (26.1 F)
1940
-5.6 C (21.9 F)
1941
-3.3 C (26.1 F)
1942
-5.6 C (21.9 F)
1943
-7.2 C (19.0 F)
1944
-1.7 C (28.9 F)
1945
-3.9 C (25.0 F)
1946
-3.9 C (25.0 F)
1947
-4.4 C (24.1 F)
1948
-4.4 C (24.1 F)
1949
-7.2 C (19.0 F)
1950
-6.1 C (21.0 F)
1951
-3.3 C (26.1 F)
1952
-4.4 C (24.1 F)
1953
-2.8 C (27.0 F)
1954
-3.9 C (25.0 F)
1955
-3.3 C (26.1 F)
Wettest day (Rx1day)
The wettest day of the year at Folsom, 1893 to 1955. The record is 96.3 mm (3.8 in) in 1906, marked on the chart; the median year is 50.3 mm (2.0 in).
Wettest day (Rx1day) at Folsom by year
Year
Wettest day (Rx1day)
1893
55.6 mm (2.2 in)
1894
73.9 mm (2.9 in)
1895
86.6 mm (3.4 in)
1896
58.9 mm (2.3 in)
1897
63.8 mm (2.5 in)
1898
22.4 mm (0.9 in)
1899
65.5 mm (2.6 in)
1900
59.7 mm (2.4 in)
1901
67.8 mm (2.7 in)
1902
38.1 mm (1.5 in)
1903
74.2 mm (2.9 in)
1904
46.2 mm (1.8 in)
1905
29.2 mm (1.1 in)
1906
96.3 mm (3.8 in)
1907
54.4 mm (2.1 in)
1908
30.0 mm (1.2 in)
1909
53.3 mm (2.1 in)
1910
51.3 mm (2.0 in)
1911
77.2 mm (3.0 in)
1912
24.6 mm (1.0 in)
1913
50.3 mm (2.0 in)
1914
63.5 mm (2.5 in)
1915
44.5 mm (1.8 in)
1916
52.3 mm (2.1 in)
1917
34.0 mm (1.3 in)
1918
58.4 mm (2.3 in)
1919
34.3 mm (1.4 in)
1920
31.8 mm (1.3 in)
1921
55.9 mm (2.2 in)
1922
62.2 mm (2.4 in)
1923
26.7 mm (1.1 in)
1924
41.4 mm (1.6 in)
1925
48.8 mm (1.9 in)
1926
47.0 mm (1.9 in)
1927
47.8 mm (1.9 in)
1928
38.6 mm (1.5 in)
1929
48.3 mm (1.9 in)
1930
31.8 mm (1.3 in)
1931
38.1 mm (1.5 in)
1932
22.1 mm (0.9 in)
1933
35.1 mm (1.4 in)
1934
32.8 mm (1.3 in)
1935
55.1 mm (2.2 in)
1936
49.0 mm (1.9 in)
1937
69.9 mm (2.8 in)
1938
41.7 mm (1.6 in)
1939
50.8 mm (2.0 in)
1940
78.0 mm (3.1 in)
1941
52.3 mm (2.1 in)
1942
51.8 mm (2.0 in)
1943
45.0 mm (1.8 in)
1944
55.4 mm (2.2 in)
1945
62.7 mm (2.5 in)
1946
53.3 mm (2.1 in)
1947
25.4 mm (1.0 in)
1948
39.6 mm (1.6 in)
1949
51.8 mm (2.0 in)
1950
51.6 mm (2.0 in)
1951
37.6 mm (1.5 in)
1952
78.7 mm (3.1 in)
1953
34.5 mm (1.4 in)
1954
49.8 mm (2.0 in)
1955
32.0 mm (1.3 in)
Wettest five days (Rx5day)
The wettest five days of the year at Folsom, 1893 to 1955. The record is 223.5 mm (8.8 in) in 1911, marked on the chart; the median year is 99.3 mm (3.9 in).
Wettest five days (Rx5day) at Folsom by year
Year
Wettest five days (Rx5day)
1893
105.4 mm (4.1 in)
1894
123.7 mm (4.9 in)
1895
106.5 mm (4.2 in)
1896
138.7 mm (5.5 in)
1897
153.0 mm (6.0 in)
1898
51.7 mm (2.0 in)
1899
90.4 mm (3.6 in)
1900
102.4 mm (4.0 in)
1901
87.6 mm (3.4 in)
1902
81.8 mm (3.2 in)
1903
143.0 mm (5.6 in)
1904
88.1 mm (3.5 in)
1905
59.4 mm (2.3 in)
1906
205.2 mm (8.1 in)
1907
113.2 mm (4.5 in)
1908
48.7 mm (1.9 in)
1909
151.8 mm (6.0 in)
1910
87.9 mm (3.5 in)
1911
223.5 mm (8.8 in)
1912
48.0 mm (1.9 in)
1913
85.8 mm (3.4 in)
1914
126.0 mm (5.0 in)
1915
99.3 mm (3.9 in)
1916
120.5 mm (4.7 in)
1917
106.3 mm (4.2 in)
1918
80.8 mm (3.2 in)
1919
64.9 mm (2.6 in)
1920
66.3 mm (2.6 in)
1921
98.5 mm (3.9 in)
1922
115.6 mm (4.6 in)
1923
79.0 mm (3.1 in)
1924
61.5 mm (2.4 in)
1925
106.9 mm (4.2 in)
1926
144.0 mm (5.7 in)
1927
89.4 mm (3.5 in)
1928
114.0 mm (4.5 in)
1929
92.2 mm (3.6 in)
1930
74.2 mm (2.9 in)
1931
109.2 mm (4.3 in)
1932
66.6 mm (2.6 in)
1933
120.2 mm (4.7 in)
1934
104.7 mm (4.1 in)
1935
82.5 mm (3.2 in)
1936
120.2 mm (4.7 in)
1937
116.6 mm (4.6 in)
1938
109.5 mm (4.3 in)
1939
83.3 mm (3.3 in)
1940
173.8 mm (6.8 in)
1941
91.5 mm (3.6 in)
1942
117.8 mm (4.6 in)
1943
131.0 mm (5.2 in)
1944
87.8 mm (3.5 in)
1945
135.0 mm (5.3 in)
1946
98.0 mm (3.9 in)
1947
59.2 mm (2.3 in)
1948
49.3 mm (1.9 in)
1949
114.8 mm (4.5 in)
1950
191.0 mm (7.5 in)
1951
85.0 mm (3.3 in)
1952
156.3 mm (6.2 in)
1953
64.3 mm (2.5 in)
1954
86.6 mm (3.4 in)
1955
67.6 mm (2.7 in)
Longest dry spell (CDD)
The longest dry spell of the year at Folsom, 1893 to 1955. The record is 157 days in 1932, marked on the chart; the median year is 105 days.
Longest dry spell (CDD) at Folsom by year
Year
Longest dry spell (CDD)
1893
102 days
1894
104 days
1895
95 days
1896
99 days
1897
93 days
1898
115 days
1899
72 days
1900
112 days
1901
68 days
1902
68 days
1903
74 days
1904
113 days
1905
123 days
1906
89 days
1907
133 days
1908
87 days
1909
102 days
1910
88 days
1911
85 days
1912
71 days
1913
156 days
1914
106 days
1915
39 days
1916
38 days
1917
16 days
1918
18 days
1919
43 days
1920
5 days
1921
30 days
1922
31 days
1923
53 days
1924
34 days
1925
19 days
1926
62 days
1927
140 days
1928
140 days
1929
106 days
1930
109 days
1931
127 days
1932
157 days
1933
137 days
1934
109 days
1935
133 days
1936
145 days
1937
107 days
1938
121 days
1939
110 days
1940
145 days
1941
110 days
1942
105 days
1943
140 days
1944
105 days
1945
124 days
1946
112 days
1947
121 days
1948
132 days
1949
99 days
1950
127 days
1951
143 days
1952
72 days
1953
125 days
1954
77 days
1955
129 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
42 years with a frost
Across 42 years with a frost, the median last spring frost at Folsom falls on 1 March and the median first autumn frost on 26 November, which leaves a median of 281 days between them.
Fitted over all years, the growing season changes by -9.0 days per decade at this station.
Frost dates and growing season at Folsom
Measure
Median, all years
Earliest period
Recent period (1924 to 1954)
Recent against earliest
Fitted trend
Last spring frost
1 March
n/a
13 March
n/a
+7.3 days per decade
First autumn frost
26 November
n/a
23 November
n/a
-1.6 days per decade
Growing days
281 days
n/a
251 days
n/a
-9.0 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, 1893 to 1954
A day with at least 48.3 mm (1.9 in) of rain is expected about once in 2 years. A day with at least 96.6 mm (3.8 in) of rain is expected about once in 100 years.
Rainfall return levels at Folsom: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
48.3 mm (1.9 in)
5 years
63.5 mm (2.5 in)
10 years
72.6 mm (2.9 in)
25 years
83.1 mm (3.3 in)
50 years
90.2 mm (3.6 in)
Longer than the 47 years of record
100 years
96.6 mm (3.8 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 1893 to 1954.
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: 96.3 mm (3.8 in) in 1906; 86.6 mm (3.4 in) in 1895; 78.7 mm (3.1 in) in 1952.
Station Changes
2 suspected
2 changes were suspected in the annual mean temperature of Folsom, at 1922 and 1948. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1922 ran 0.7 C (1.2 F) lower than in the years before (likely change).
Relative to 5 neighbouring stations, the station's annual mean temperature from 1948 ran 0.4 C (0.8 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at Folsom, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1922
-0.6
-1.2
likely
5
1948
+0.4
+0.8
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 Folsom standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Folsom 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.