Record envelope, standing records and threshold days for Alderpoint (USC00040088), California, United States, with 41 years of record.
Key Facts for Alderpoint
Alderpoint (USC00040088) is a weather station in California, United States at 40.18 latitude and -123.62 longitude, 140 m (459 ft) above sea level.
The station reports from 1940 to 1980, 41 years of record.
1,464 records set at Alderpoint still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Alderpoint set a daily record low minimum temperature of 1.7 C (35.1 F) on 25 May 1980.
About the Station
Location: California, United States, 40.18 latitude, -123.62 longitude.
Elevation: 140 m (459 ft).
Period of record: 1940 to 1980, 41 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 Alderpoint. 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 Alderpoint, 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)
-8.9 C (16.0 F)
n/a
n/a
Feb
27.2 C (81.0 F)
-7.2 C (19.0 F)
n/a
n/a
Mar
31.1 C (88.0 F)
-3.9 C (25.0 F)
n/a
n/a
Apr
36.7 C (98.1 F)
-3.9 C (25.0 F)
n/a
n/a
May
38.9 C (102.0 F)
-4.4 C (24.1 F)
n/a
n/a
Jun
42.2 C (108.0 F)
0.0 C (32.0 F)
n/a
n/a
Jul
46.7 C (116.1 F)
2.8 C (37.0 F)
n/a
n/a
Aug
45.6 C (114.1 F)
4.4 C (39.9 F)
n/a
n/a
Sep
45.0 C (113.0 F)
-1.1 C (30.0 F)
n/a
n/a
Oct
38.9 C (102.0 F)
-4.4 C (24.1 F)
n/a
n/a
Nov
32.8 C (91.0 F)
-5.6 C (21.9 F)
n/a
n/a
Dec
25.6 C (78.1 F)
-12.8 C (9.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Alderpoint still stand. 1945 holds the most, with 67.
Standing records at Alderpoint by the year they were set
Year set
Standing records
1941
21
1942
44
1943
47
1944
50
1945
67
1946
18
1947
30
1948
19
1949
48
1950
41
1951
30
1952
29
1953
41
1954
42
1955
47
1956
30
1957
32
1958
51
1959
38
1960
39
1961
27
1962
47
1963
37
1964
40
1965
44
1966
27
1967
34
1968
40
1969
37
1970
49
1971
34
1972
55
1973
43
1974
19
1975
23
1976
26
1977
35
1978
48
1979
27
1980
8
Wettest Day of Each Month
Dec: 148.6 mm (5.9 in)
The wettest day on record for each calendar month at Alderpoint. The most was 148.6 mm (5.9 in) on 22 December 1964.
Record daily precipitation for each month at Alderpoint
Month
Record daily precipitation (mm)
Date
Jan
125.7 mm (4.9 in)
4 January 1966
Feb
94.0 mm (3.7 in)
1 February 1963
Mar
88.1 mm (3.5 in)
26 March 1971
Apr
58.4 mm (2.3 in)
27 April 1953
May
69.1 mm (2.7 in)
18 May 1957
Jun
28.4 mm (1.1 in)
6 June 1953
Jul
11.4 mm (0.4 in)
8 July 1974
Aug
36.8 mm (1.4 in)
22 August 1968
Sep
62.5 mm (2.5 in)
27 September 1957
Oct
120.7 mm (4.8 in)
28 October 1950
Nov
101.6 mm (4.0 in)
26 November 1962
Dec
148.6 mm (5.9 in)
22 December 1964
Period of Record Coverage
1941 to 1980
Complete yearUnder 90 percent of days
40 years of record at Alderpoint, 1941 to 1980. 12 years have data for under 90 percent of days and are left out of rankings: 1941, 1945, 1946, 1947, 1948, 1949, 1950, 1974 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 22 complete years at Alderpoint, 1942 to 1979. Blue stripes are years cooler than the station's own mean of 14.1 C (57.4 F); red stripes are warmer. The coolest year was 1955, at 13.1 C (55.7 F), and the warmest was 1943, at 15.5 C (59.9 F). The strongest colour marks a difference of 1.4 C (2.5 F).
Annual mean temperature at Alderpoint as warming stripes, 1942 to 1979
Year
Annual mean temperature
Difference from the station mean
1942
14.7 C
+0.56 C
1943
15.5 C
+1.36 C
1944
14.3 C
+0.15 C
1951
14.5 C
+0.40 C
1953
13.9 C
-0.22 C
1954
13.6 C
-0.59 C
1955
13.1 C
-1.00 C
1956
13.5 C
-0.65 C
1957
13.7 C
-0.44 C
1958
15.4 C
+1.30 C
1959
14.4 C
+0.26 C
1960
14.5 C
+0.33 C
1962
14.0 C
-0.10 C
1963
13.9 C
-0.20 C
1964
13.8 C
-0.31 C
1966
14.3 C
+0.13 C
1967
14.2 C
+0.10 C
1968
14.1 C
-0.03 C
1970
14.3 C
+0.20 C
1971
13.2 C
-0.91 C
1972
13.7 C
-0.41 C
1979
14.2 C
+0.02 C
This station does not have enough complete years (30 are needed) to fit a temperature trend.
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
1940 to 1980
Yearly extremes at Alderpoint: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
46.7 C (116.1 F)
1972
41.7 C (107.1 F)
40
Coldest night (TNn)
-12.8 C (9.0 F)
1972
-5.8 C (21.5 F)
40
Wettest day (Rx1day)
148.6 mm (5.9 in)
1964
81.0 mm (3.2 in)
41
Wettest five days (Rx5day)
397.8 mm (15.7 in)
1964
190.3 mm (7.5 in)
41
Longest dry spell (CDD)
158 days
1970
75 days
41
Hottest day (TXx)
The hottest day of the year at Alderpoint, 1940 to 1980. The record is 46.7 C (116.1 F) in 1972, marked on the chart; the median year is 41.7 C (107.1 F).
Hottest day (TXx) at Alderpoint by year
Year
Hottest day (TXx)
1940
n/a
1941
41.7 C (107.1 F)
1942
41.7 C (107.1 F)
1943
43.3 C (109.9 F)
1944
44.4 C (111.9 F)
1945
42.2 C (108.0 F)
1946
40.0 C (104.0 F)
1947
38.3 C (100.9 F)
1948
40.6 C (105.1 F)
1949
37.2 C (99.0 F)
1950
42.2 C (108.0 F)
1951
41.1 C (106.0 F)
1952
40.6 C (105.1 F)
1953
40.0 C (104.0 F)
1954
40.0 C (104.0 F)
1955
45.0 C (113.0 F)
1956
43.3 C (109.9 F)
1957
40.0 C (104.0 F)
1958
43.9 C (111.0 F)
1959
45.6 C (114.1 F)
1960
42.2 C (108.0 F)
1961
43.9 C (111.0 F)
1962
41.1 C (106.0 F)
1963
41.1 C (106.0 F)
1964
42.2 C (108.0 F)
1965
38.9 C (102.0 F)
1966
41.7 C (107.1 F)
1967
40.6 C (105.1 F)
1968
40.0 C (104.0 F)
1969
41.1 C (106.0 F)
1970
42.8 C (109.0 F)
1971
43.3 C (109.9 F)
1972
46.7 C (116.1 F)
1973
43.3 C (109.9 F)
1974
43.3 C (109.9 F)
1975
42.2 C (108.0 F)
1976
39.4 C (102.9 F)
1977
42.2 C (108.0 F)
1978
44.4 C (111.9 F)
1979
40.6 C (105.1 F)
1980
28.9 C (84.0 F)
Coldest night (TNn)
The coldest night of the year at Alderpoint, 1940 to 1980. The record is -12.8 C (9.0 F) in 1972, marked on the chart; the median year is -5.8 C (21.5 F).
Coldest night (TNn) at Alderpoint by year
Year
Coldest night (TNn)
1940
n/a
1941
-3.3 C (26.1 F)
1942
-3.9 C (25.0 F)
1943
-7.2 C (19.0 F)
1944
-2.8 C (27.0 F)
1945
-4.4 C (24.1 F)
1946
-3.9 C (25.0 F)
1947
2.8 C (37.0 F)
1948
-6.7 C (19.9 F)
1949
-8.9 C (16.0 F)
1950
-7.2 C (19.0 F)
1951
-6.1 C (21.0 F)
1952
-4.4 C (24.1 F)
1953
-3.3 C (26.1 F)
1954
-4.4 C (24.1 F)
1955
-3.9 C (25.0 F)
1956
-6.7 C (19.9 F)
1957
-6.7 C (19.9 F)
1958
-3.9 C (25.0 F)
1959
-6.1 C (21.0 F)
1960
-6.1 C (21.0 F)
1961
-5.6 C (21.9 F)
1962
-7.2 C (19.0 F)
1963
-7.2 C (19.0 F)
1964
-3.9 C (25.0 F)
1965
-7.2 C (19.0 F)
1966
-3.3 C (26.1 F)
1967
-6.7 C (19.9 F)
1968
-3.3 C (26.1 F)
1969
-3.9 C (25.0 F)
1970
-4.4 C (24.1 F)
1971
-4.4 C (24.1 F)
1972
-12.8 C (9.0 F)
1973
-6.1 C (21.0 F)
1974
-3.3 C (26.1 F)
1975
-3.3 C (26.1 F)
1976
-6.1 C (21.0 F)
1977
-6.1 C (21.0 F)
1978
-7.8 C (18.0 F)
1979
-6.7 C (19.9 F)
1980
-6.7 C (19.9 F)
Wettest day (Rx1day)
The wettest day of the year at Alderpoint, 1940 to 1980. The record is 148.6 mm (5.9 in) in 1964, marked on the chart; the median year is 81.0 mm (3.2 in).
Wettest day (Rx1day) at Alderpoint by year
Year
Wettest day (Rx1day)
1940
91.4 mm (3.6 in)
1941
53.8 mm (2.1 in)
1942
73.7 mm (2.9 in)
1943
114.3 mm (4.5 in)
1944
53.8 mm (2.1 in)
1945
58.4 mm (2.3 in)
1946
76.7 mm (3.0 in)
1947
16.5 mm (0.6 in)
1948
50.8 mm (2.0 in)
1949
70.4 mm (2.8 in)
1950
120.7 mm (4.8 in)
1951
87.6 mm (3.4 in)
1952
82.0 mm (3.2 in)
1953
83.1 mm (3.3 in)
1954
101.6 mm (4.0 in)
1955
128.5 mm (5.1 in)
1956
91.4 mm (3.6 in)
1957
69.1 mm (2.7 in)
1958
91.2 mm (3.6 in)
1959
68.1 mm (2.7 in)
1960
93.0 mm (3.7 in)
1961
69.1 mm (2.7 in)
1962
101.6 mm (4.0 in)
1963
94.0 mm (3.7 in)
1964
148.6 mm (5.9 in)
1965
74.7 mm (2.9 in)
1966
125.7 mm (4.9 in)
1967
80.0 mm (3.1 in)
1968
86.4 mm (3.4 in)
1969
99.1 mm (3.9 in)
1970
86.4 mm (3.4 in)
1971
92.7 mm (3.6 in)
1972
47.0 mm (1.9 in)
1973
81.0 mm (3.2 in)
1974
37.6 mm (1.5 in)
1975
76.2 mm (3.0 in)
1976
30.0 mm (1.2 in)
1977
58.4 mm (2.3 in)
1978
71.6 mm (2.8 in)
1979
96.5 mm (3.8 in)
1980
76.2 mm (3.0 in)
Wettest five days (Rx5day)
The wettest five days of the year at Alderpoint, 1940 to 1980. The record is 397.8 mm (15.7 in) in 1964, marked on the chart; the median year is 190.3 mm (7.5 in).
Wettest five days (Rx5day) at Alderpoint by year
Year
Wettest five days (Rx5day)
1940
244.4 mm (9.6 in)
1941
141.5 mm (5.6 in)
1942
212.8 mm (8.4 in)
1943
234.7 mm (9.2 in)
1944
170.4 mm (6.7 in)
1945
157.3 mm (6.2 in)
1946
179.6 mm (7.1 in)
1947
42.1 mm (1.7 in)
1948
89.5 mm (3.5 in)
1949
161.3 mm (6.4 in)
1950
333.6 mm (13.1 in)
1951
203.9 mm (8.0 in)
1952
245.1 mm (9.6 in)
1953
153.3 mm (6.0 in)
1954
202.4 mm (8.0 in)
1955
310.1 mm (12.2 in)
1956
209.5 mm (8.2 in)
1957
163.9 mm (6.5 in)
1958
190.3 mm (7.5 in)
1959
202.3 mm (8.0 in)
1960
245.1 mm (9.6 in)
1961
136.2 mm (5.4 in)
1962
327.6 mm (12.9 in)
1963
218.7 mm (8.6 in)
1964
397.8 mm (15.7 in)
1965
165.5 mm (6.5 in)
1966
292.6 mm (11.5 in)
1967
166.1 mm (6.5 in)
1968
191.9 mm (7.6 in)
1969
205.7 mm (8.1 in)
1970
260.9 mm (10.3 in)
1971
172.4 mm (6.8 in)
1972
137.0 mm (5.4 in)
1973
224.0 mm (8.8 in)
1974
61.7 mm (2.4 in)
1975
181.2 mm (7.1 in)
1976
60.2 mm (2.4 in)
1977
152.8 mm (6.0 in)
1978
186.2 mm (7.3 in)
1979
152.9 mm (6.0 in)
1980
193.2 mm (7.6 in)
Longest dry spell (CDD)
The longest dry spell of the year at Alderpoint, 1940 to 1980. The record is 158 days in 1970, marked on the chart; the median year is 75 days.
Longest dry spell (CDD) at Alderpoint by year
Year
Longest dry spell (CDD)
1940
13 days
1941
47 days
1942
106 days
1943
113 days
1944
110 days
1945
89 days
1946
45 days
1947
47 days
1948
24 days
1949
34 days
1950
87 days
1951
125 days
1952
110 days
1953
76 days
1954
70 days
1955
136 days
1956
75 days
1957
73 days
1958
58 days
1959
111 days
1960
131 days
1961
58 days
1962
87 days
1963
87 days
1964
138 days
1965
113 days
1966
55 days
1967
105 days
1968
74 days
1969
91 days
1970
158 days
1971
64 days
1972
65 days
1973
117 days
1974
82 days
1975
54 days
1976
56 days
1977
73 days
1978
68 days
1979
62 days
1980
16 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
22 years with a frost
Across 22 years with a frost, the median last spring frost at Alderpoint falls on 30 March and the median first autumn frost on 13 November, which leaves a median of 229 days between them.
Frost dates and growing season at Alderpoint
Measure
Median, all years
Earliest period
Recent period (1942 to 1979)
Recent against earliest
Fitted trend
Last spring frost
30 March
n/a
30 March
n/a
n/a
First autumn frost
13 November
n/a
13 November
n/a
n/a
Growing days
229 days
n/a
229 days
n/a
n/a
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
31 years, 1942 to 1979
A day with at least 85.5 mm (3.4 in) of rain is expected about once in 2 years. A day with at least 152.4 mm (6.0 in) of rain is expected about once in 100 years.
Rainfall return levels at Alderpoint: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
85.5 mm (3.4 in)
5 years
106.3 mm (4.2 in)
10 years
118.8 mm (4.7 in)
25 years
133.3 mm (5.2 in)
50 years
143.2 mm (5.6 in)
Longer than the 31 years of record
100 years
152.4 mm (6.0 in)
Longer than the 31 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, 31 years of values from 1942 to 1979.
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: 148.6 mm (5.9 in) in 1964; 128.5 mm (5.1 in) in 1955; 125.7 mm (4.9 in) in 1966.
Download the Data
Data for Alderpoint standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Alderpoint 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.