Record envelope, standing records and threshold days for Palo Alto (USC00046642), California, United States, with 48 years of record.
Key Facts for Palo Alto
Palo Alto (USC00046642) is a weather station in California, United States at 37.43 latitude and -122.17 longitude, 18 m (59 ft) above sea level.
The station reports from 1906 to 1953, 48 years of record.
1,464 records set at Palo Alto still stand.
Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
Palo Alto set a daily record precipitation of 1.5 mm (0.06 in) on 30 August 1953.
About the Station
Location: California, United States, 37.43 latitude, -122.17 longitude.
Elevation: 18 m (59 ft).
Period of record: 1906 to 1953, 48 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 Palo Alto. 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 Palo Alto, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
23.9 C (75.0 F)
-6.7 C (19.9 F)
n/a
n/a
Feb
26.1 C (79.0 F)
-3.9 C (25.0 F)
n/a
n/a
Mar
28.9 C (84.0 F)
-3.9 C (25.0 F)
n/a
n/a
Apr
32.8 C (91.0 F)
-0.6 C (30.9 F)
n/a
n/a
May
36.1 C (97.0 F)
2.2 C (36.0 F)
n/a
n/a
Jun
38.9 C (102.0 F)
4.4 C (39.9 F)
n/a
n/a
Jul
40.6 C (105.1 F)
4.4 C (39.9 F)
n/a
n/a
Aug
37.8 C (100.0 F)
6.7 C (44.1 F)
n/a
n/a
Sep
39.4 C (102.9 F)
3.9 C (39.0 F)
n/a
n/a
Oct
35.0 C (95.0 F)
0.0 C (32.0 F)
n/a
n/a
Nov
28.9 C (84.0 F)
-3.3 C (26.1 F)
n/a
n/a
Dec
23.9 C (75.0 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 Palo Alto still stand. 1929 holds the most, with 81.
Standing records at Palo Alto by the year they were set
Year set
Standing records
1922
3
1923
67
1924
71
1925
43
1926
69
1927
61
1928
49
1929
81
1930
42
1931
47
1932
52
1933
63
1934
40
1935
57
1936
53
1937
48
1938
40
1939
47
1940
37
1941
31
1942
20
1943
27
1944
27
1945
43
1946
36
1947
32
1948
27
1949
53
1950
56
1951
55
1952
52
1953
35
Wettest Day of Each Month
Jan: 89.7 mm (3.5 in)
The wettest day on record for each calendar month at Palo Alto. The most was 89.7 mm (3.5 in) on 14 January 1911.
Record daily precipitation for each month at Palo Alto
Month
Record daily precipitation (mm)
Date
Jan
89.7 mm (3.5 in)
14 January 1911
Feb
48.3 mm (1.9 in)
21 February 1914
Mar
58.4 mm (2.3 in)
6 March 1911
Apr
26.7 mm (1.1 in)
5 April 1941
May
24.4 mm (1.0 in)
5 May 1915
Jun
20.3 mm (0.8 in)
23 June 1912
Jul
19.1 mm (0.8 in)
22 July 1913
Aug
8.6 mm (0.34 in)
27 August 1935
Sep
20.8 mm (0.8 in)
25 September 1923
Oct
30.5 mm (1.2 in)
10 October 1947
Nov
65.0 mm (2.6 in)
19 November 1950
Dec
76.2 mm (3.0 in)
28 December 1913
Period of Record Coverage
1922 to 1953
Complete yearUnder 90 percent of days
32 years of record at Palo Alto, 1922 to 1953. 4 years have data for under 90 percent of days and are left out of rankings: 1922, 1930, 1931, 1953.
Cooler than the station meanWarmer than the station mean
One stripe for each of 28 complete years at Palo Alto, 1923 to 1952. Blue stripes are years cooler than the station's own mean of 14.0 C (57.1 F); red stripes are warmer. The coolest year was 1933, at 13.2 C (55.8 F), and the warmest was 1926, at 14.9 C (58.8 F). The strongest colour marks a difference of 1.0 C (1.8 F).
Annual mean temperature at Palo Alto as warming stripes, 1923 to 1952
Year
Annual mean temperature
Difference from the station mean
1923
13.6 C
-0.38 C
1924
13.7 C
-0.22 C
1925
14.2 C
+0.22 C
1926
14.9 C
+0.95 C
1927
14.1 C
+0.09 C
1928
14.0 C
+0.04 C
1929
14.1 C
+0.13 C
1932
13.3 C
-0.65 C
1933
13.2 C
-0.72 C
1934
14.7 C
+0.77 C
1935
13.6 C
-0.39 C
1936
14.5 C
+0.55 C
1937
13.7 C
-0.22 C
1938
13.9 C
-0.08 C
1939
14.1 C
+0.15 C
1940
14.7 C
+0.76 C
1941
14.6 C
+0.64 C
1942
13.5 C
-0.51 C
1943
14.0 C
+0.01 C
1944
13.7 C
-0.29 C
1945
13.8 C
-0.12 C
1946
13.5 C
-0.48 C
1947
14.2 C
+0.20 C
1948
13.3 C
-0.63 C
1949
13.7 C
-0.30 C
1950
14.5 C
+0.51 C
1951
13.9 C
-0.10 C
1952
13.9 C
-0.03 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
1906 to 1953
Yearly extremes at Palo Alto: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
40.6 C (105.1 F)
1931
36.7 C (98.1 F)
32
Coldest night (TNn)
-6.7 C (19.9 F)
1937
-2.2 C (28.0 F)
32
Wettest day (Rx1day)
89.7 mm (3.5 in)
1911
31.0 mm (1.2 in)
45
Wettest five days (Rx5day)
198.9 mm (7.8 in)
1911
68.1 mm (2.7 in)
43
Longest dry spell (CDD)
178 days
1928
108 days
43
Hottest day (TXx)
The hottest day of the year at Palo Alto, 1906 to 1953. The record is 40.6 C (105.1 F) in 1931, marked on the chart; the median year is 36.7 C (98.1 F).
Hottest day (TXx) at Palo Alto by year
Year
Hottest day (TXx)
1906
n/a
1907
n/a
1908
n/a
1909
n/a
1910
n/a
1911
n/a
1912
n/a
1913
n/a
1914
n/a
1915
n/a
1916
n/a
1917
n/a
1918
n/a
1922
16.7 C (62.1 F)
1923
35.6 C (96.1 F)
1924
36.7 C (98.1 F)
1925
38.3 C (100.9 F)
1926
36.1 C (97.0 F)
1927
37.8 C (100.0 F)
1928
37.2 C (99.0 F)
1929
38.9 C (102.0 F)
1930
36.7 C (98.1 F)
1931
40.6 C (105.1 F)
1932
36.7 C (98.1 F)
1933
33.3 C (91.9 F)
1934
38.9 C (102.0 F)
1935
35.6 C (96.1 F)
1936
36.1 C (97.0 F)
1937
37.2 C (99.0 F)
1938
32.8 C (91.0 F)
1939
37.8 C (100.0 F)
1940
32.8 C (91.0 F)
1941
33.9 C (93.0 F)
1942
33.9 C (93.0 F)
1943
36.7 C (98.1 F)
1944
38.9 C (102.0 F)
1945
37.2 C (99.0 F)
1946
37.8 C (100.0 F)
1947
35.6 C (96.1 F)
1948
36.1 C (97.0 F)
1949
35.6 C (96.1 F)
1950
39.4 C (102.9 F)
1951
37.2 C (99.0 F)
1952
35.0 C (95.0 F)
1953
33.9 C (93.0 F)
Coldest night (TNn)
The coldest night of the year at Palo Alto, 1906 to 1953. The record is -6.7 C (19.9 F) in 1937, marked on the chart; the median year is -2.2 C (28.0 F).
Coldest night (TNn) at Palo Alto by year
Year
Coldest night (TNn)
1906
n/a
1907
n/a
1908
n/a
1909
n/a
1910
n/a
1911
n/a
1912
n/a
1913
n/a
1914
n/a
1915
n/a
1916
n/a
1917
n/a
1918
n/a
1922
-1.1 C (30.0 F)
1923
-3.9 C (25.0 F)
1924
-5.6 C (21.9 F)
1925
-2.2 C (28.0 F)
1926
-2.2 C (28.0 F)
1927
-2.2 C (28.0 F)
1928
-3.9 C (25.0 F)
1929
-3.9 C (25.0 F)
1930
-2.8 C (27.0 F)
1931
-3.3 C (26.1 F)
1932
-5.0 C (23.0 F)
1933
-2.8 C (27.0 F)
1934
0.6 C (33.1 F)
1935
-1.7 C (28.9 F)
1936
-1.1 C (30.0 F)
1937
-6.7 C (19.9 F)
1938
-1.1 C (30.0 F)
1939
-1.1 C (30.0 F)
1940
-3.9 C (25.0 F)
1941
-1.1 C (30.0 F)
1942
-2.2 C (28.0 F)
1943
-4.4 C (24.1 F)
1944
0.0 C (32.0 F)
1945
-2.2 C (28.0 F)
1946
-2.2 C (28.0 F)
1947
-2.8 C (27.0 F)
1948
-2.8 C (27.0 F)
1949
-6.7 C (19.9 F)
1950
-4.4 C (24.1 F)
1951
-1.7 C (28.9 F)
1952
-2.2 C (28.0 F)
1953
0.0 C (32.0 F)
Wettest day (Rx1day)
The wettest day of the year at Palo Alto, 1906 to 1953. The record is 89.7 mm (3.5 in) in 1911, marked on the chart; the median year is 31.0 mm (1.2 in).
Wettest day (Rx1day) at Palo Alto by year
Year
Wettest day (Rx1day)
1906
31.5 mm (1.2 in)
1907
43.4 mm (1.7 in)
1908
26.9 mm (1.1 in)
1909
48.3 mm (1.9 in)
1910
24.1 mm (0.9 in)
1911
89.7 mm (3.5 in)
1912
20.3 mm (0.8 in)
1913
76.2 mm (3.0 in)
1914
48.3 mm (1.9 in)
1915
58.7 mm (2.3 in)
1916
44.5 mm (1.8 in)
1917
43.2 mm (1.7 in)
1918
15.2 mm (0.6 in)
1922
28.2 mm (1.1 in)
1923
20.8 mm (0.8 in)
1924
24.9 mm (1.0 in)
1925
28.7 mm (1.1 in)
1926
35.1 mm (1.4 in)
1927
19.1 mm (0.8 in)
1928
27.2 mm (1.1 in)
1929
13.7 mm (0.5 in)
1930
24.9 mm (1.0 in)
1931
36.6 mm (1.4 in)
1932
29.2 mm (1.1 in)
1933
20.8 mm (0.8 in)
1934
30.2 mm (1.2 in)
1935
21.8 mm (0.9 in)
1936
36.8 mm (1.4 in)
1937
45.2 mm (1.8 in)
1938
27.2 mm (1.1 in)
1939
27.7 mm (1.1 in)
1940
39.1 mm (1.5 in)
1941
35.1 mm (1.4 in)
1942
41.1 mm (1.6 in)
1943
38.1 mm (1.5 in)
1944
25.1 mm (1.0 in)
1945
44.5 mm (1.8 in)
1946
46.7 mm (1.8 in)
1947
30.5 mm (1.2 in)
1948
35.6 mm (1.4 in)
1949
23.9 mm (0.9 in)
1950
65.0 mm (2.6 in)
1951
31.0 mm (1.2 in)
1952
56.4 mm (2.2 in)
1953
17.0 mm (0.7 in)
Wettest five days (Rx5day)
The wettest five days of the year at Palo Alto, 1906 to 1953. The record is 198.9 mm (7.8 in) in 1911, marked on the chart; the median year is 68.1 mm (2.7 in).
Wettest five days (Rx5day) at Palo Alto by year
Year
Wettest five days (Rx5day)
1906
54.9 mm (2.2 in)
1907
129.3 mm (5.1 in)
1908
35.9 mm (1.4 in)
1909
102.0 mm (4.0 in)
1910
n/a
1911
198.9 mm (7.8 in)
1912
40.9 mm (1.6 in)
1913
31.3 mm (1.2 in)
1914
118.2 mm (4.7 in)
1915
89.2 mm (3.5 in)
1916
68.1 mm (2.7 in)
1917
99.0 mm (3.9 in)
1918
n/a
1922
50.6 mm (2.0 in)
1923
31.4 mm (1.2 in)
1924
36.5 mm (1.4 in)
1925
47.5 mm (1.9 in)
1926
87.7 mm (3.5 in)
1927
47.3 mm (1.9 in)
1928
53.1 mm (2.1 in)
1929
28.5 mm (1.1 in)
1930
69.2 mm (2.7 in)
1931
102.1 mm (4.0 in)
1932
69.3 mm (2.7 in)
1933
57.9 mm (2.3 in)
1934
55.9 mm (2.2 in)
1935
46.2 mm (1.8 in)
1936
69.8 mm (2.7 in)
1937
87.9 mm (3.5 in)
1938
80.6 mm (3.2 in)
1939
38.1 mm (1.5 in)
1940
122.4 mm (4.8 in)
1941
64.0 mm (2.5 in)
1942
70.6 mm (2.8 in)
1943
107.9 mm (4.2 in)
1944
57.4 mm (2.3 in)
1945
90.2 mm (3.6 in)
1946
87.4 mm (3.4 in)
1947
32.8 mm (1.3 in)
1948
49.8 mm (2.0 in)
1949
48.5 mm (1.9 in)
1950
129.0 mm (5.1 in)
1951
113.8 mm (4.5 in)
1952
81.7 mm (3.2 in)
1953
35.2 mm (1.4 in)
Longest dry spell (CDD)
The longest dry spell of the year at Palo Alto, 1906 to 1953. The record is 178 days in 1928, marked on the chart; the median year is 108 days.
Longest dry spell (CDD) at Palo Alto by year
Year
Longest dry spell (CDD)
1906
6 days
1907
n/a
1908
1 day
1909
1 day
1910
1 day
1911
25 days
1912
23 days
1913
5 days
1914
28 days
1915
14 days
1916
17 days
1917
n/a
1918
1 day
1922
7 days
1923
98 days
1924
145 days
1925
108 days
1926
146 days
1927
140 days
1928
178 days
1929
113 days
1930
85 days
1931
128 days
1932
154 days
1933
161 days
1934
108 days
1935
118 days
1936
145 days
1937
108 days
1938
138 days
1939
111 days
1940
124 days
1941
159 days
1942
105 days
1943
172 days
1944
142 days
1945
164 days
1946
59 days
1947
101 days
1948
92 days
1949
72 days
1950
134 days
1951
88 days
1952
119 days
1953
84 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
21 years with a frost
Across 21 years with a frost, the median last spring frost at Palo Alto falls on 20 February and the median first autumn frost on 23 November, which leaves a median of 279 days between them.
Frost dates and growing season at Palo Alto
Measure
Median, all years
Earliest period
Recent period (1923 to 1951)
Recent against earliest
Fitted trend
Last spring frost
20 February
n/a
20 February
n/a
n/a
First autumn frost
23 November
n/a
23 November
n/a
n/a
Growing days
279 days
n/a
279 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.
Download the Data
Data for Palo Alto standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Palo Alto 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.