Record envelope, standing records and threshold days for Hillsboro (USC00353908), Oregon, United States, with 75 years of record.
Key Facts for Hillsboro
Hillsboro (USC00353908) is a weather station in Oregon, United States at 45.51 latitude and -122.99 longitude, 49 m (160 ft) above sea level.
The station reports from 1929 to 2003, 75 years of record.
1,464 records set at Hillsboro still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Hillsboro tied a daily record low minimum temperature of 1.1 C (34.0 F) on 19 May 2003.
About the Station
Location: Oregon, United States, 45.51 latitude, -122.99 longitude.
Elevation: 49 m (160 ft).
Period of record: 1929 to 2003, 75 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 Hillsboro. 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 Hillsboro, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
20.6 C (69.1 F)
-25.6 C (-14.1 F)
n/a
n/a
Feb
21.1 C (70.0 F)
-22.8 C (-9.0 F)
n/a
n/a
Mar
28.3 C (82.9 F)
-7.8 C (18.0 F)
n/a
n/a
Apr
32.2 C (90.0 F)
-6.7 C (19.9 F)
n/a
n/a
May
37.8 C (100.0 F)
-5.6 C (21.9 F)
n/a
n/a
Jun
38.9 C (102.0 F)
-1.1 C (30.0 F)
n/a
n/a
Jul
42.2 C (108.0 F)
2.2 C (36.0 F)
n/a
n/a
Aug
41.1 C (106.0 F)
-1.1 C (30.0 F)
n/a
n/a
Sep
39.4 C (102.9 F)
-1.7 C (28.9 F)
n/a
n/a
Oct
33.3 C (91.9 F)
-6.1 C (21.0 F)
n/a
n/a
Nov
25.6 C (78.1 F)
-13.3 C (8.1 F)
n/a
n/a
Dec
17.8 C (64.0 F)
-18.9 C (-2.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Hillsboro still stand. 1930 holds the most, with 51.
Standing records at Hillsboro by the year they were set
Year set
Standing records
1929
4
1930
51
1931
21
1932
22
1933
28
1934
33
1935
48
1936
43
1937
23
1938
15
1939
18
1940
17
1941
14
1942
18
1943
16
1944
21
1945
14
1946
7
1947
22
1948
19
1949
23
1950
28
1951
24
1952
29
1953
19
1954
9
1955
34
1956
26
1957
21
1958
35
1959
14
1960
33
1961
27
1962
27
1963
25
1964
25
1965
30
1966
14
1967
10
1968
21
1969
9
1970
17
1971
17
1972
39
1973
12
1974
15
1975
11
1976
13
1977
21
1978
18
1979
17
1980
16
1981
11
1982
12
1983
10
1984
5
1985
29
1986
23
1987
21
1988
7
1989
13
1990
19
1991
20
1992
15
1993
7
1994
8
1995
12
1996
18
1997
19
1998
30
1999
11
2000
10
2001
9
2002
17
2003
5
All-Time Record Progression
4 new records
4 all-time records were set at Hillsboro between 12 August 1977 and 18 November 1996. Each dot is a new record.
When Hillsboro set new all-time records
Date
Kind
Detail
1977-08-12
Record high minimum temperature
Record high minimum temperature 23.3 C (73.9 F)
1989-02-03
Record low maximum temperature
Record low maximum temperature -9.4 C (15.1 F)
1989-02-04
Record low maximum temperature
Record low maximum temperature -10.0 C (14.0 F)
1996-11-18
Record daily precipitation
Record daily precipitation 86.4 mm (3.4 in)
Wettest Day of Each Month
Nov: 86.4 mm (3.4 in)
The wettest day on record for each calendar month at Hillsboro. The most was 86.4 mm (3.4 in) on 18 November 1996.
Record daily precipitation for each month at Hillsboro
Month
Record daily precipitation (mm)
Date
Jan
72.1 mm (2.8 in)
15 January 1974
Feb
68.1 mm (2.7 in)
10 February 1949
Mar
47.5 mm (1.9 in)
30 March 1943
Apr
46.2 mm (1.8 in)
5 April 1991
May
29.7 mm (1.2 in)
13 May 1978
Jun
51.8 mm (2.0 in)
7 June 1985
Jul
31.8 mm (1.3 in)
19 July 1983
Aug
33.8 mm (1.3 in)
1 August 1985
Sep
43.7 mm (1.7 in)
4 September 1945
Oct
66.0 mm (2.6 in)
26 October 1994
Nov
86.4 mm (3.4 in)
18 November 1996
Dec
84.1 mm (3.3 in)
27 December 1937
Period of Record Coverage
1929 to 2003
Complete yearUnder 90 percent of days
75 years of record at Hillsboro, 1929 to 2003. 6 years have data for under 90 percent of days and are left out of rankings: 1929, 1999, 2000, 2001, 2002, 2003.
Cooler than the station meanWarmer than the station mean
One stripe for each of 67 complete years at Hillsboro, 1930 to 1998. Blue stripes are years cooler than the station's own mean of 11.3 C (52.3 F); red stripes are warmer. The coolest year was 1985, at 10.0 C (49.9 F), and the warmest was 1998, at 13.5 C (56.2 F). The strongest colour marks a difference of 2.2 C (4.0 F).
Annual mean temperature at Hillsboro as warming stripes, 1930 to 1998
Year
Annual mean temperature
Difference from the station mean
1930
10.0 C
-1.29 C
1931
11.3 C
+0.03 C
1932
11.1 C
-0.19 C
1935
10.3 C
-1.02 C
1936
11.1 C
-0.23 C
1937
11.1 C
-0.15 C
1938
11.3 C
+0.02 C
1939
11.4 C
+0.14 C
1940
12.2 C
+0.91 C
1941
11.9 C
+0.56 C
1942
10.7 C
-0.60 C
1943
10.7 C
-0.55 C
1944
11.0 C
-0.32 C
1945
11.1 C
-0.19 C
1946
11.0 C
-0.27 C
1947
11.5 C
+0.23 C
1948
10.5 C
-0.79 C
1949
11.0 C
-0.31 C
1950
10.9 C
-0.35 C
1951
11.5 C
+0.21 C
1952
11.6 C
+0.26 C
1953
11.8 C
+0.53 C
1954
10.8 C
-0.48 C
1955
10.1 C
-1.23 C
1956
11.0 C
-0.26 C
1957
11.5 C
+0.19 C
1958
13.3 C
+2.03 C
1959
11.0 C
-0.26 C
1960
11.1 C
-0.20 C
1961
12.3 C
+0.97 C
1962
11.0 C
-0.30 C
1963
11.0 C
-0.30 C
1964
10.0 C
-1.31 C
1965
10.9 C
-0.35 C
1966
11.0 C
-0.25 C
1967
11.9 C
+0.60 C
1968
11.3 C
+0.00 C
1969
11.1 C
-0.23 C
1970
11.3 C
+0.05 C
1971
11.0 C
-0.31 C
1972
11.3 C
+0.00 C
1973
11.3 C
+0.04 C
1974
11.6 C
+0.28 C
1975
11.0 C
-0.29 C
1976
10.9 C
-0.39 C
1977
11.2 C
-0.12 C
1978
11.3 C
+0.04 C
1979
11.4 C
+0.10 C
1980
11.0 C
-0.33 C
1981
11.7 C
+0.38 C
1982
10.7 C
-0.59 C
1983
11.4 C
+0.08 C
1984
10.7 C
-0.58 C
1985
10.0 C
-1.33 C
1986
11.8 C
+0.49 C
1987
12.1 C
+0.80 C
1988
11.4 C
+0.10 C
1989
11.1 C
-0.21 C
1990
11.5 C
+0.16 C
1991
11.5 C
+0.18 C
1992
12.6 C
+1.33 C
1993
11.0 C
-0.30 C
1994
11.6 C
+0.31 C
1995
12.4 C
+1.06 C
1996
11.6 C
+0.33 C
1997
12.5 C
+1.24 C
1998
13.5 C
+2.17 C
The annual mean temperature here has risen by 0.11 C (0.03 to 0.19) per decade over 1930 to 1998. In Fahrenheit: 0.2 F (0.1 to 0.3) per decade. The slope is a straight line fitted to 67 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Hillsboro
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.11 C (0.03 to 0.19) per decade
0.2 F (0.1 to 0.3) per decade
1930 to 1998
67
Rise
Mean daily maximum
-0.01 C (-0.10 to 0.07) per decade
-0.03 F (-0.18 to 0.13) per decade
1930 to 1998
67
Not clearly different from zero
Mean daily minimum
0.2 C (0.1 to 0.3) per decade
0.4 F (0.2 to 0.6) per decade
1930 to 1998
67
Rise
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
1929 to 2003
Yearly extremes at Hillsboro: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
42.2 C (108.0 F)
1956
37.8 C (100.0 F)
75
Coldest night (TNn)
-25.6 C (-14.1 F)
1930
-8.9 C (16.0 F)
75
Wettest day (Rx1day)
86.4 mm (3.4 in)
1996
43.2 mm (1.7 in)
75
Wettest five days (Rx5day)
216.2 mm (8.5 in)
1937
102.6 mm (4.0 in)
75
Longest dry spell (CDD)
97 days
1967
39 days
75
Hottest day (TXx)
The hottest day of the year at Hillsboro, 1929 to 2003. The record is 42.2 C (108.0 F) in 1956, marked on the chart; the median year is 37.8 C (100.0 F).
Hottest day (TXx) at Hillsboro by year
Year
Hottest day (TXx)
1929
17.8 C (64.0 F)
1930
36.7 C (98.1 F)
1931
40.6 C (105.1 F)
1932
37.8 C (100.0 F)
1933
37.8 C (100.0 F)
1934
35.6 C (96.1 F)
1935
41.7 C (107.1 F)
1936
36.7 C (98.1 F)
1937
36.1 C (97.0 F)
1938
40.6 C (105.1 F)
1939
39.4 C (102.9 F)
1940
36.1 C (97.0 F)
1941
40.0 C (104.0 F)
1942
38.3 C (100.9 F)
1943
34.4 C (93.9 F)
1944
39.4 C (102.9 F)
1945
37.2 C (99.0 F)
1946
39.4 C (102.9 F)
1947
33.3 C (91.9 F)
1948
35.6 C (96.1 F)
1949
36.1 C (97.0 F)
1950
36.7 C (98.1 F)
1951
38.3 C (100.9 F)
1952
40.0 C (104.0 F)
1953
38.3 C (100.9 F)
1954
31.7 C (89.1 F)
1955
37.2 C (99.0 F)
1956
42.2 C (108.0 F)
1957
35.6 C (96.1 F)
1958
40.6 C (105.1 F)
1959
36.1 C (97.0 F)
1960
38.9 C (102.0 F)
1961
40.6 C (105.1 F)
1962
35.6 C (96.1 F)
1963
36.7 C (98.1 F)
1964
33.9 C (93.0 F)
1965
38.9 C (102.0 F)
1966
32.8 C (91.0 F)
1967
37.8 C (100.0 F)
1968
34.4 C (93.9 F)
1969
35.6 C (96.1 F)
1970
37.8 C (100.0 F)
1971
39.4 C (102.9 F)
1972
40.0 C (104.0 F)
1973
36.1 C (97.0 F)
1974
36.7 C (98.1 F)
1975
36.1 C (97.0 F)
1976
34.4 C (93.9 F)
1977
41.1 C (106.0 F)
1978
39.4 C (102.9 F)
1979
38.3 C (100.9 F)
1980
38.3 C (100.9 F)
1981
40.0 C (104.0 F)
1982
36.7 C (98.1 F)
1983
37.8 C (100.0 F)
1984
36.7 C (98.1 F)
1985
38.3 C (100.9 F)
1986
37.8 C (100.0 F)
1987
38.3 C (100.9 F)
1988
39.4 C (102.9 F)
1989
34.4 C (93.9 F)
1990
37.8 C (100.0 F)
1991
36.7 C (98.1 F)
1992
38.9 C (102.0 F)
1993
37.2 C (99.0 F)
1994
38.3 C (100.9 F)
1995
36.7 C (98.1 F)
1996
38.3 C (100.9 F)
1997
35.0 C (95.0 F)
1998
40.6 C (105.1 F)
1999
33.3 C (91.9 F)
2000
27.8 C (82.0 F)
2001
34.4 C (93.9 F)
2002
38.3 C (100.9 F)
2003
31.1 C (88.0 F)
Coldest night (TNn)
The coldest night of the year at Hillsboro, 1929 to 2003. The record is -25.6 C (-14.1 F) in 1930, marked on the chart; the median year is -8.9 C (16.0 F).
Coldest night (TNn) at Hillsboro by year
Year
Coldest night (TNn)
1929
-5.6 C (21.9 F)
1930
-25.6 C (-14.1 F)
1931
-7.2 C (19.0 F)
1932
-15.0 C (5.0 F)
1933
-11.7 C (10.9 F)
1934
-4.4 C (24.1 F)
1935
-12.2 C (10.0 F)
1936
-10.0 C (14.0 F)
1937
-17.2 C (1.0 F)
1938
-7.8 C (18.0 F)
1939
-5.6 C (21.9 F)
1940
-7.8 C (18.0 F)
1941
-5.0 C (23.0 F)
1942
-11.1 C (12.0 F)
1943
-18.9 C (-2.0 F)
1944
-7.8 C (18.0 F)
1945
-7.8 C (18.0 F)
1946
-7.8 C (18.0 F)
1947
-8.9 C (16.0 F)
1948
-8.3 C (17.1 F)
1949
-16.1 C (3.0 F)
1950
-23.3 C (-9.9 F)
1951
-11.1 C (12.0 F)
1952
-9.4 C (15.1 F)
1953
-3.3 C (26.1 F)
1954
-12.2 C (10.0 F)
1955
-13.3 C (8.1 F)
1956
-13.9 C (7.0 F)
1957
-15.0 C (5.0 F)
1958
-5.6 C (21.9 F)
1959
-10.0 C (14.0 F)
1960
-7.8 C (18.0 F)
1961
-7.2 C (19.0 F)
1962
-12.2 C (10.0 F)
1963
-12.8 C (9.0 F)
1964
-13.3 C (8.1 F)
1965
-8.9 C (16.0 F)
1966
-3.9 C (25.0 F)
1967
-6.1 C (21.0 F)
1968
-13.3 C (8.1 F)
1969
-9.4 C (15.1 F)
1970
-3.9 C (25.0 F)
1971
-6.7 C (19.9 F)
1972
-18.9 C (-2.0 F)
1973
-7.2 C (19.0 F)
1974
-12.2 C (10.0 F)
1975
-4.4 C (24.1 F)
1976
-6.7 C (19.9 F)
1977
-10.6 C (12.9 F)
1978
-10.0 C (14.0 F)
1979
-13.3 C (8.1 F)
1980
-12.2 C (10.0 F)
1981
-3.3 C (26.1 F)
1982
-11.1 C (12.0 F)
1983
-12.2 C (10.0 F)
1984
-9.4 C (15.1 F)
1985
-12.8 C (9.0 F)
1986
-3.9 C (25.0 F)
1987
-5.6 C (21.9 F)
1988
-6.1 C (21.0 F)
1989
-13.3 C (8.1 F)
1990
-14.4 C (6.1 F)
1991
-7.2 C (19.0 F)
1992
-5.0 C (23.0 F)
1993
-10.6 C (12.9 F)
1994
-5.6 C (21.9 F)
1995
-7.8 C (18.0 F)
1996
-10.6 C (12.9 F)
1997
-5.6 C (21.9 F)
1998
-12.2 C (10.0 F)
1999
-2.2 C (28.0 F)
2000
-2.2 C (28.0 F)
2001
-5.6 C (21.9 F)
2002
-6.1 C (21.0 F)
2003
-3.3 C (26.1 F)
Wettest day (Rx1day)
The wettest day of the year at Hillsboro, 1929 to 2003. The record is 86.4 mm (3.4 in) in 1996, marked on the chart; the median year is 43.2 mm (1.7 in).
Wettest day (Rx1day) at Hillsboro by year
Year
Wettest day (Rx1day)
1929
33.8 mm (1.3 in)
1930
34.0 mm (1.3 in)
1931
43.2 mm (1.7 in)
1932
41.9 mm (1.6 in)
1933
54.9 mm (2.2 in)
1934
44.7 mm (1.8 in)
1935
35.6 mm (1.4 in)
1936
69.1 mm (2.7 in)
1937
84.1 mm (3.3 in)
1938
34.3 mm (1.4 in)
1939
38.9 mm (1.5 in)
1940
38.9 mm (1.5 in)
1941
60.2 mm (2.4 in)
1942
50.8 mm (2.0 in)
1943
57.7 mm (2.3 in)
1944
27.9 mm (1.1 in)
1945
68.6 mm (2.7 in)
1946
53.3 mm (2.1 in)
1947
28.2 mm (1.1 in)
1948
42.2 mm (1.7 in)
1949
68.1 mm (2.7 in)
1950
41.4 mm (1.6 in)
1951
45.0 mm (1.8 in)
1952
32.5 mm (1.3 in)
1953
36.8 mm (1.4 in)
1954
56.9 mm (2.2 in)
1955
71.4 mm (2.8 in)
1956
49.3 mm (1.9 in)
1957
33.5 mm (1.3 in)
1958
36.1 mm (1.4 in)
1959
35.1 mm (1.4 in)
1960
55.1 mm (2.2 in)
1961
40.6 mm (1.6 in)
1962
71.1 mm (2.8 in)
1963
50.8 mm (2.0 in)
1964
42.4 mm (1.7 in)
1965
39.9 mm (1.6 in)
1966
46.5 mm (1.8 in)
1967
33.8 mm (1.3 in)
1968
51.1 mm (2.0 in)
1969
35.8 mm (1.4 in)
1970
41.4 mm (1.6 in)
1971
33.5 mm (1.3 in)
1972
50.8 mm (2.0 in)
1973
68.3 mm (2.7 in)
1974
72.1 mm (2.8 in)
1975
35.1 mm (1.4 in)
1976
37.8 mm (1.5 in)
1977
49.0 mm (1.9 in)
1978
29.7 mm (1.2 in)
1979
38.1 mm (1.5 in)
1980
48.0 mm (1.9 in)
1981
36.3 mm (1.4 in)
1982
65.5 mm (2.6 in)
1983
43.2 mm (1.7 in)
1984
48.5 mm (1.9 in)
1985
51.8 mm (2.0 in)
1986
34.3 mm (1.4 in)
1987
59.2 mm (2.3 in)
1988
27.9 mm (1.1 in)
1989
29.2 mm (1.1 in)
1990
40.1 mm (1.6 in)
1991
46.2 mm (1.8 in)
1992
38.4 mm (1.5 in)
1993
40.1 mm (1.6 in)
1994
66.0 mm (2.6 in)
1995
48.3 mm (1.9 in)
1996
86.4 mm (3.4 in)
1997
40.9 mm (1.6 in)
1998
48.8 mm (1.9 in)
1999
44.2 mm (1.7 in)
2000
27.4 mm (1.1 in)
2001
45.5 mm (1.8 in)
2002
43.2 mm (1.7 in)
2003
41.4 mm (1.6 in)
Wettest five days (Rx5day)
The wettest five days of the year at Hillsboro, 1929 to 2003. The record is 216.2 mm (8.5 in) in 1937, marked on the chart; the median year is 102.6 mm (4.0 in).
Wettest five days (Rx5day) at Hillsboro by year
Year
Wettest five days (Rx5day)
1929
95.9 mm (3.8 in)
1930
49.4 mm (1.9 in)
1931
88.9 mm (3.5 in)
1932
123.7 mm (4.9 in)
1933
144.0 mm (5.7 in)
1934
152.9 mm (6.0 in)
1935
66.9 mm (2.6 in)
1936
105.4 mm (4.1 in)
1937
216.2 mm (8.5 in)
1938
94.1 mm (3.7 in)
1939
89.9 mm (3.5 in)
1940
92.5 mm (3.6 in)
1941
155.7 mm (6.1 in)
1942
111.5 mm (4.4 in)
1943
136.5 mm (5.4 in)
1944
60.4 mm (2.4 in)
1945
136.9 mm (5.4 in)
1946
121.9 mm (4.8 in)
1947
102.6 mm (4.0 in)
1948
88.7 mm (3.5 in)
1949
108.0 mm (4.3 in)
1950
112.5 mm (4.4 in)
1951
91.0 mm (3.6 in)
1952
83.6 mm (3.3 in)
1953
96.6 mm (3.8 in)
1954
83.0 mm (3.3 in)
1955
140.9 mm (5.5 in)
1956
118.3 mm (4.7 in)
1957
85.6 mm (3.4 in)
1958
64.5 mm (2.5 in)
1959
126.5 mm (5.0 in)
1960
125.4 mm (4.9 in)
1961
91.5 mm (3.6 in)
1962
90.7 mm (3.6 in)
1963
104.8 mm (4.1 in)
1964
155.0 mm (6.1 in)
1965
112.1 mm (4.4 in)
1966
115.6 mm (4.6 in)
1967
79.5 mm (3.1 in)
1968
103.9 mm (4.1 in)
1969
92.3 mm (3.6 in)
1970
89.8 mm (3.5 in)
1971
89.4 mm (3.5 in)
1972
117.4 mm (4.6 in)
1973
130.2 mm (5.1 in)
1974
172.9 mm (6.8 in)
1975
77.2 mm (3.0 in)
1976
79.0 mm (3.1 in)
1977
132.8 mm (5.2 in)
1978
61.5 mm (2.4 in)
1979
72.7 mm (2.9 in)
1980
106.9 mm (4.2 in)
1981
73.5 mm (2.9 in)
1982
130.5 mm (5.1 in)
1983
91.2 mm (3.6 in)
1984
98.8 mm (3.9 in)
1985
65.6 mm (2.6 in)
1986
80.0 mm (3.1 in)
1987
119.3 mm (4.7 in)
1988
83.1 mm (3.3 in)
1989
60.0 mm (2.4 in)
1990
120.6 mm (4.7 in)
1991
79.2 mm (3.1 in)
1992
71.9 mm (2.8 in)
1993
111.8 mm (4.4 in)
1994
106.7 mm (4.2 in)
1995
110.4 mm (4.3 in)
1996
180.5 mm (7.1 in)
1997
149.0 mm (5.9 in)
1998
137.1 mm (5.4 in)
1999
94.8 mm (3.7 in)
2000
61.0 mm (2.4 in)
2001
102.8 mm (4.0 in)
2002
125.5 mm (4.9 in)
2003
91.9 mm (3.6 in)
Longest dry spell (CDD)
The longest dry spell of the year at Hillsboro, 1929 to 2003. The record is 97 days in 1967, marked on the chart; the median year is 39 days.
Longest dry spell (CDD) at Hillsboro by year
Year
Longest dry spell (CDD)
1929
14 days
1930
49 days
1931
71 days
1932
27 days
1933
38 days
1934
36 days
1935
28 days
1936
42 days
1937
17 days
1938
42 days
1939
50 days
1940
50 days
1941
39 days
1942
33 days
1943
27 days
1944
36 days
1945
37 days
1946
51 days
1947
33 days
1948
20 days
1949
38 days
1950
31 days
1951
76 days
1952
54 days
1953
39 days
1954
39 days
1955
48 days
1956
26 days
1957
34 days
1958
63 days
1959
54 days
1960
56 days
1961
39 days
1962
50 days
1963
26 days
1964
25 days
1965
45 days
1966
55 days
1967
97 days
1968
24 days
1969
76 days
1970
62 days
1971
54 days
1972
34 days
1973
59 days
1974
30 days
1975
33 days
1976
26 days
1977
28 days
1978
29 days
1979
38 days
1980
57 days
1981
47 days
1982
16 days
1983
35 days
1984
62 days
1985
53 days
1986
61 days
1987
42 days
1988
74 days
1989
34 days
1990
41 days
1991
51 days
1992
39 days
1993
52 days
1994
49 days
1995
31 days
1996
31 days
1997
19 days
1998
48 days
1999
28 days
2000
21 days
2001
32 days
2002
79 days
2003
12 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
67 years with a frost
Across 67 years with a frost, the median last spring frost at Hillsboro falls on 29 April and the median first autumn frost on 23 October, which leaves a median of 182 days between them.
In 1969 to 1998 the median growing season was 196 days. That is 19 days more than in 1930 to 1961.
Fitted over all years, the growing season changes by +9.0 days per decade at this station.
Frost dates and growing season at Hillsboro
Measure
Median, all years
Earliest period (1930 to 1961)
Recent period (1969 to 1998)
Recent against earliest
Fitted trend
Last spring frost
29 April
1 May
16 April
15 days earlier
-5.5 days per decade
First autumn frost
23 October
23 October
27 October
4 days later
+3.5 days per decade
Growing days
182 days
177 days
196 days
19 days more
+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
70 years, 1930 to 2002
A day with at least 44.1 mm (1.7 in) of rain is expected about once in 2 years. A day with at least 94.7 mm (3.7 in) of rain is expected about once in 100 years.
Rainfall return levels at Hillsboro: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
44.1 mm (1.7 in)
5 years
56.2 mm (2.2 in)
10 years
64.8 mm (2.6 in)
25 years
76.3 mm (3.0 in)
50 years
85.3 mm (3.4 in)
100 years
94.7 mm (3.7 in)
Longer than the 70 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, 70 years of values from 1930 to 2002.
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: 86.4 mm (3.4 in) in 1996; 84.1 mm (3.3 in) in 1937; 72.1 mm (2.8 in) in 1974.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Hillsboro, at 1959. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1959 ran 0.4 C (0.6 F) lower than in the years before (possible change).
Suspected changes in the annual mean temperature at Hillsboro, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1959
-0.3
-0.6
possible
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 Hillsboro standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Hillsboro 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.