Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Rosta. 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 Rosta, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
9.6 C (49.3 F)
-39.6 C (-39.3 F)
n/a
n/a
Feb
9.8 C (49.6 F)
-34.6 C (-30.3 F)
n/a
n/a
Mar
18.0 C (64.4 F)
-29.6 C (-21.3 F)
n/a
n/a
Apr
20.5 C (68.9 F)
-18.2 C (-0.8 F)
n/a
n/a
May
27.5 C (81.5 F)
-7.6 C (18.3 F)
n/a
n/a
Jun
34.3 C (93.7 F)
-2.6 C (27.3 F)
n/a
n/a
Jul
31.5 C (88.7 F)
1.0 C (33.8 F)
n/a
n/a
Aug
31.3 C (88.3 F)
0.0 C (32.0 F)
n/a
n/a
Sep
25.1 C (77.2 F)
-5.0 C (23.0 F)
n/a
n/a
Oct
18.2 C (64.8 F)
-17.1 C (1.2 F)
n/a
n/a
Nov
11.5 C (52.7 F)
-24.1 C (-11.4 F)
n/a
n/a
Dec
10.1 C (50.2 F)
-37.5 C (-35.5 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Rosta still stand. 1966 holds the most, with 46.
Standing records at Rosta by the year they were set
Year set
Standing records
1941
36
1942
37
1943
12
1944
20
1945
17
1946
12
1947
36
1948
20
1949
25
1950
16
1951
17
1952
24
1953
30
1954
4
1955
42
1956
19
1957
20
1958
28
1959
19
1960
13
1961
23
1962
14
1963
13
1964
20
1965
15
1966
46
1967
13
1968
38
1969
22
1970
17
1971
21
1972
11
1973
27
1974
7
1975
21
1976
18
1977
23
1978
28
1979
16
1980
12
1981
31
1982
11
1983
6
1984
9
1985
27
1986
17
1987
22
1988
13
1989
19
1990
24
1991
25
1992
31
1993
27
1994
11
1995
20
1996
8
1997
16
1998
17
1999
25
2000
20
2001
8
2002
41
2003
20
2004
20
2005
23
2006
25
2007
13
2008
9
2009
19
2010
31
2011
24
All-Time Record Progression
5 new records
5 all-time records were set at Rosta between 31 December 1978 and 27 August 2001. Each dot is a new record.
When Rosta set new all-time records
Date
Kind
Detail
1978-12-31
Record low maximum temperature
Record low maximum temperature -33.0 C (-27.4 F)
1978-12-31
Record low minimum temperature
Record low minimum temperature -37.5 C (-35.5 F)
1987-01-10
Record low minimum temperature
Record low minimum temperature -39.6 C (-39.3 F)
2000-07-19
Record daily precipitation
Record daily precipitation 46.1 mm (1.8 in)
2001-08-27
Record daily precipitation
Record daily precipitation 54.2 mm (2.1 in)
Wettest Day of Each Month
Aug: 54.2 mm (2.1 in)
The wettest day on record for each calendar month at Rosta. The most was 54.2 mm (2.1 in) on 27 August 2001.
Record daily precipitation for each month at Rosta
Month
Record daily precipitation (mm)
Date
Jan
21.7 mm (0.9 in)
29 January 1966
Feb
21.2 mm (0.8 in)
11 February 1997
Mar
28.1 mm (1.1 in)
19 March 2002
Apr
31.0 mm (1.2 in)
20 April 1945
May
31.3 mm (1.2 in)
28 May 1982
Jun
38.8 mm (1.5 in)
26 June 1978
Jul
52.4 mm (2.1 in)
20 July 2009
Aug
54.2 mm (2.1 in)
27 August 2001
Sep
37.5 mm (1.5 in)
4 September 1985
Oct
31.0 mm (1.2 in)
7 October 1993
Nov
25.6 mm (1.0 in)
23 November 1981
Dec
25.5 mm (1.0 in)
5 December 1986
Period of Record Coverage
1941 to 2011
Complete yearUnder 90 percent of days
71 years of record at Rosta, 1941 to 2011. Every year has data for at least 90 percent of its days.
Cooler than the station meanWarmer than the station mean
One stripe for each of 71 complete years at Rosta, 1941 to 2011. Blue stripes are years cooler than the station's own mean of 2.9 C (37.1 F); red stripes are warmer. The coolest year was 1985, at 0.6 C (33.1 F), and the warmest was 2011, at 5.0 C (40.9 F). The strongest colour marks a difference of 2.3 C (4.1 F).
Annual mean temperature at Rosta as warming stripes, 1941 to 2011
Year
Annual mean temperature
Difference from the station mean
1941
1.3 C
-1.59 C
1942
1.2 C
-1.62 C
1943
3.8 C
+0.96 C
1944
3.2 C
+0.32 C
1945
3.0 C
+0.17 C
1946
3.1 C
+0.28 C
1947
2.7 C
-0.13 C
1948
3.8 C
+0.93 C
1949
4.1 C
+1.25 C
1950
2.8 C
-0.03 C
1951
2.3 C
-0.55 C
1952
1.2 C
-1.62 C
1953
4.3 C
+1.39 C
1954
2.8 C
-0.09 C
1955
1.6 C
-1.27 C
1956
1.7 C
-1.14 C
1957
2.8 C
-0.05 C
1958
1.3 C
-1.60 C
1959
3.7 C
+0.80 C
1960
2.1 C
-0.75 C
1961
3.6 C
+0.71 C
1962
1.5 C
-1.37 C
1963
2.4 C
-0.45 C
1964
3.1 C
+0.28 C
1965
1.9 C
-0.98 C
1966
0.7 C
-2.15 C
1967
2.6 C
-0.26 C
1968
1.7 C
-1.12 C
1969
2.1 C
-0.75 C
1970
1.8 C
-1.03 C
1971
2.9 C
+0.06 C
1972
3.4 C
+0.55 C
1973
3.3 C
+0.42 C
1974
3.5 C
+0.63 C
1975
4.1 C
+1.27 C
1976
2.1 C
-0.76 C
1977
2.0 C
-0.86 C
1978
1.6 C
-1.28 C
1979
1.6 C
-1.26 C
1980
2.1 C
-0.73 C
1981
1.6 C
-1.29 C
1982
2.9 C
+0.02 C
1983
3.2 C
+0.37 C
1984
3.3 C
+0.43 C
1985
0.6 C
-2.24 C
1986
2.1 C
-0.73 C
1987
1.7 C
-1.19 C
1988
3.4 C
+0.52 C
1989
4.5 C
+1.61 C
1990
4.4 C
+1.54 C
1991
3.6 C
+0.76 C
1992
3.6 C
+0.75 C
1993
2.8 C
-0.08 C
1994
2.4 C
-0.43 C
1995
3.1 C
+0.23 C
1996
2.5 C
-0.35 C
1997
3.9 C
+1.00 C
1998
3.3 C
+0.43 C
1999
3.4 C
+0.58 C
2000
4.3 C
+1.43 C
2001
3.0 C
+0.15 C
2002
4.3 C
+1.42 C
2003
4.1 C
+1.21 C
2004
4.0 C
+1.13 C
2005
4.1 C
+1.24 C
2006
4.6 C
+1.74 C
2007
4.1 C
+1.20 C
2008
4.0 C
+1.18 C
2009
3.2 C
+0.31 C
2010
1.1 C
-1.81 C
2011
5.0 C
+2.10 C
The annual mean temperature here has risen by 0.2 C (0.1 to 0.3) per decade over 1941 to 2011. In Fahrenheit: 0.3 F (0.1 to 0.5) per decade. The slope is a straight line fitted to 71 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Rosta
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.2 C (0.1 to 0.3) per decade
0.3 F (0.1 to 0.5) per decade
1941 to 2011
71
Rise
Mean daily maximum
0.08 C (-0.04 to 0.20) per decade
0.1 F (-0.1 to 0.4) per decade
1941 to 2011
71
Not clearly different from zero
Mean daily minimum
0.3 C (0.2 to 0.4) per decade
0.5 F (0.3 to 0.7) per decade
1941 to 2011
71
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
1941 to 2011
Yearly extremes at Rosta: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
34.3 C (93.7 F)
1947
27.9 C (82.2 F)
71
Coldest night (TNn)
-39.6 C (-39.3 F)
1987
-28.0 C (-18.4 F)
71
Wettest day (Rx1day)
54.2 mm (2.1 in)
2001
28.1 mm (1.1 in)
68
Wettest five days (Rx5day)
98.0 mm (3.9 in)
1960
51.3 mm (2.0 in)
68
Longest dry spell (CDD)
52 days
2003
24 days
68
Hottest day (TXx)
The hottest day of the year at Rosta, 1941 to 2011. The record is 34.3 C (93.7 F) in 1947, marked on the chart; the median year is 27.9 C (82.2 F).
Hottest day (TXx) at Rosta by year
Year
Hottest day (TXx)
1941
30.2 C (86.4 F)
1942
28.0 C (82.4 F)
1943
29.8 C (85.6 F)
1944
30.2 C (86.4 F)
1945
31.5 C (88.7 F)
1946
28.0 C (82.4 F)
1947
34.3 C (93.7 F)
1948
28.0 C (82.4 F)
1949
28.0 C (82.4 F)
1950
26.0 C (78.8 F)
1951
25.5 C (77.9 F)
1952
29.5 C (85.1 F)
1953
30.0 C (86.0 F)
1954
26.0 C (78.8 F)
1955
31.0 C (87.8 F)
1956
28.0 C (82.4 F)
1957
27.0 C (80.6 F)
1958
28.5 C (83.3 F)
1959
26.0 C (78.8 F)
1960
26.8 C (80.2 F)
1961
27.0 C (80.6 F)
1962
22.0 C (71.6 F)
1963
25.7 C (78.3 F)
1964
25.1 C (77.2 F)
1965
26.3 C (79.3 F)
1966
28.9 C (84.0 F)
1967
25.2 C (77.4 F)
1968
29.4 C (84.9 F)
1969
28.3 C (82.9 F)
1970
27.2 C (81.0 F)
1971
27.3 C (81.1 F)
1972
28.4 C (83.1 F)
1973
29.0 C (84.2 F)
1974
28.0 C (82.4 F)
1975
28.9 C (84.0 F)
1976
26.0 C (78.8 F)
1977
27.5 C (81.5 F)
1978
28.0 C (82.4 F)
1979
27.0 C (80.6 F)
1980
27.7 C (81.9 F)
1981
27.9 C (82.2 F)
1982
28.2 C (82.8 F)
1983
27.6 C (81.7 F)
1984
27.1 C (80.8 F)
1985
25.8 C (78.4 F)
1986
28.5 C (83.3 F)
1987
24.8 C (76.6 F)
1988
28.9 C (84.0 F)
1989
29.0 C (84.2 F)
1990
25.4 C (77.7 F)
1991
29.8 C (85.6 F)
1992
26.8 C (80.2 F)
1993
25.0 C (77.0 F)
1994
29.1 C (84.4 F)
1995
26.8 C (80.2 F)
1996
25.7 C (78.3 F)
1997
27.4 C (81.3 F)
1998
24.1 C (75.4 F)
1999
27.7 C (81.9 F)
2000
26.9 C (80.4 F)
2001
27.1 C (80.8 F)
2002
27.5 C (81.5 F)
2003
30.9 C (87.6 F)
2004
28.3 C (82.9 F)
2005
28.7 C (83.7 F)
2006
29.5 C (85.1 F)
2007
28.6 C (83.5 F)
2008
30.3 C (86.5 F)
2009
27.6 C (81.7 F)
2010
26.6 C (79.9 F)
2011
28.6 C (83.5 F)
Coldest night (TNn)
The coldest night of the year at Rosta, 1941 to 2011. The record is -39.6 C (-39.3 F) in 1987, marked on the chart; the median year is -28.0 C (-18.4 F).
Coldest night (TNn) at Rosta by year
Year
Coldest night (TNn)
1941
-29.3 C (-20.7 F)
1942
-31.5 C (-24.7 F)
1943
-26.0 C (-14.8 F)
1944
-22.0 C (-7.6 F)
1945
-31.0 C (-23.8 F)
1946
-26.0 C (-14.8 F)
1947
-31.0 C (-23.8 F)
1948
-28.0 C (-18.4 F)
1949
-26.2 C (-15.2 F)
1950
-34.5 C (-30.1 F)
1951
-27.3 C (-17.1 F)
1952
-27.7 C (-17.9 F)
1953
-28.0 C (-18.4 F)
1954
-28.5 C (-19.3 F)
1955
-31.0 C (-23.8 F)
1956
-32.0 C (-25.6 F)
1957
-23.5 C (-10.3 F)
1958
-30.0 C (-22.0 F)
1959
-27.0 C (-16.6 F)
1960
-29.0 C (-20.2 F)
1961
-28.5 C (-19.3 F)
1962
-25.3 C (-13.5 F)
1963
-30.0 C (-22.0 F)
1964
-27.0 C (-16.6 F)
1965
-28.3 C (-18.9 F)
1966
-34.6 C (-30.3 F)
1967
-31.7 C (-25.1 F)
1968
-25.8 C (-14.4 F)
1969
-32.9 C (-27.2 F)
1970
-29.7 C (-21.5 F)
1971
-29.6 C (-21.3 F)
1972
-24.8 C (-12.6 F)
1973
-26.3 C (-15.3 F)
1974
-26.4 C (-15.5 F)
1975
-20.9 C (-5.6 F)
1976
-29.7 C (-21.5 F)
1977
-29.4 C (-20.9 F)
1978
-37.5 C (-35.5 F)
1979
-33.9 C (-29.0 F)
1980
-31.7 C (-25.1 F)
1981
-31.4 C (-24.5 F)
1982
-31.8 C (-25.2 F)
1983
-27.0 C (-16.6 F)
1984
-30.4 C (-22.7 F)
1985
-34.2 C (-29.6 F)
1986
-30.6 C (-23.1 F)
1987
-39.6 C (-39.3 F)
1988
-25.0 C (-13.0 F)
1989
-27.0 C (-16.6 F)
1990
-24.1 C (-11.4 F)
1991
-24.2 C (-11.6 F)
1992
-17.1 C (1.2 F)
1993
-28.0 C (-18.4 F)
1994
-28.0 C (-18.4 F)
1995
-21.2 C (-6.2 F)
1996
-23.6 C (-10.5 F)
1997
-26.0 C (-14.8 F)
1998
-21.4 C (-6.5 F)
1999
-32.7 C (-26.9 F)
2000
-25.5 C (-13.9 F)
2001
-30.8 C (-23.4 F)
2002
-25.7 C (-14.3 F)
2003
-28.0 C (-18.4 F)
2004
-27.2 C (-17.0 F)
2005
-25.4 C (-13.7 F)
2006
-24.8 C (-12.6 F)
2007
-24.7 C (-12.5 F)
2008
-22.5 C (-8.5 F)
2009
-26.5 C (-15.7 F)
2010
-33.0 C (-27.4 F)
2011
-24.1 C (-11.4 F)
Wettest day (Rx1day)
The wettest day of the year at Rosta, 1941 to 2011. The record is 54.2 mm (2.1 in) in 2001, marked on the chart; the median year is 28.1 mm (1.1 in).
Wettest day (Rx1day) at Rosta by year
Year
Wettest day (Rx1day)
1941
n/a
1942
n/a
1943
4.1 mm (0.16 in)
1944
n/a
1945
45.5 mm (1.8 in)
1946
21.4 mm (0.8 in)
1947
27.1 mm (1.1 in)
1948
21.4 mm (0.8 in)
1949
14.0 mm (0.6 in)
1950
43.2 mm (1.7 in)
1951
18.8 mm (0.7 in)
1952
28.4 mm (1.1 in)
1953
27.8 mm (1.1 in)
1954
31.2 mm (1.2 in)
1955
24.6 mm (1.0 in)
1956
29.2 mm (1.1 in)
1957
22.5 mm (0.9 in)
1958
25.8 mm (1.0 in)
1959
17.4 mm (0.7 in)
1960
42.7 mm (1.7 in)
1961
29.8 mm (1.2 in)
1962
19.8 mm (0.8 in)
1963
18.3 mm (0.7 in)
1964
32.2 mm (1.3 in)
1965
26.8 mm (1.1 in)
1966
28.0 mm (1.1 in)
1967
34.8 mm (1.4 in)
1968
16.4 mm (0.6 in)
1969
25.5 mm (1.0 in)
1970
22.3 mm (0.9 in)
1971
24.2 mm (1.0 in)
1972
30.0 mm (1.2 in)
1973
25.6 mm (1.0 in)
1974
44.6 mm (1.8 in)
1975
30.1 mm (1.2 in)
1976
30.7 mm (1.2 in)
1977
17.4 mm (0.7 in)
1978
38.8 mm (1.5 in)
1979
30.8 mm (1.2 in)
1980
31.8 mm (1.3 in)
1981
38.5 mm (1.5 in)
1982
31.3 mm (1.2 in)
1983
27.4 mm (1.1 in)
1984
23.9 mm (0.9 in)
1985
37.5 mm (1.5 in)
1986
27.3 mm (1.1 in)
1987
28.5 mm (1.1 in)
1988
36.7 mm (1.4 in)
1989
14.4 mm (0.6 in)
1990
20.4 mm (0.8 in)
1991
26.1 mm (1.0 in)
1992
31.5 mm (1.2 in)
1993
31.0 mm (1.2 in)
1994
19.1 mm (0.8 in)
1995
23.0 mm (0.9 in)
1996
22.0 mm (0.9 in)
1997
28.1 mm (1.1 in)
1998
35.3 mm (1.4 in)
1999
24.9 mm (1.0 in)
2000
46.1 mm (1.8 in)
2001
54.2 mm (2.1 in)
2002
28.1 mm (1.1 in)
2003
32.3 mm (1.3 in)
2004
21.9 mm (0.9 in)
2005
35.1 mm (1.4 in)
2006
35.0 mm (1.4 in)
2007
19.3 mm (0.8 in)
2008
37.2 mm (1.5 in)
2009
52.4 mm (2.1 in)
2010
29.8 mm (1.2 in)
2011
31.4 mm (1.2 in)
Wettest five days (Rx5day)
The wettest five days of the year at Rosta, 1941 to 2011. The record is 98.0 mm (3.9 in) in 1960, marked on the chart; the median year is 51.3 mm (2.0 in).
Wettest five days (Rx5day) at Rosta by year
Year
Wettest five days (Rx5day)
1941
n/a
1942
n/a
1943
15.4 mm (0.6 in)
1944
n/a
1945
64.5 mm (2.5 in)
1946
43.7 mm (1.7 in)
1947
33.9 mm (1.3 in)
1948
30.5 mm (1.2 in)
1949
27.7 mm (1.1 in)
1950
75.4 mm (3.0 in)
1951
28.8 mm (1.1 in)
1952
47.3 mm (1.9 in)
1953
51.9 mm (2.0 in)
1954
66.4 mm (2.6 in)
1955
40.2 mm (1.6 in)
1956
40.5 mm (1.6 in)
1957
65.8 mm (2.6 in)
1958
50.8 mm (2.0 in)
1959
29.8 mm (1.2 in)
1960
98.0 mm (3.9 in)
1961
64.5 mm (2.5 in)
1962
74.6 mm (2.9 in)
1963
35.2 mm (1.4 in)
1964
49.9 mm (2.0 in)
1965
58.5 mm (2.3 in)
1966
55.7 mm (2.2 in)
1967
45.5 mm (1.8 in)
1968
31.2 mm (1.2 in)
1969
28.5 mm (1.1 in)
1970
52.4 mm (2.1 in)
1971
40.9 mm (1.6 in)
1972
51.7 mm (2.0 in)
1973
54.3 mm (2.1 in)
1974
54.6 mm (2.1 in)
1975
41.8 mm (1.6 in)
1976
44.0 mm (1.7 in)
1977
35.5 mm (1.4 in)
1978
58.6 mm (2.3 in)
1979
56.5 mm (2.2 in)
1980
38.8 mm (1.5 in)
1981
60.4 mm (2.4 in)
1982
36.8 mm (1.4 in)
1983
59.5 mm (2.3 in)
1984
61.6 mm (2.4 in)
1985
63.1 mm (2.5 in)
1986
50.7 mm (2.0 in)
1987
68.9 mm (2.7 in)
1988
71.0 mm (2.8 in)
1989
43.8 mm (1.7 in)
1990
34.7 mm (1.4 in)
1991
50.4 mm (2.0 in)
1992
56.5 mm (2.2 in)
1993
57.4 mm (2.3 in)
1994
33.0 mm (1.3 in)
1995
48.4 mm (1.9 in)
1996
44.5 mm (1.8 in)
1997
54.5 mm (2.1 in)
1998
74.9 mm (2.9 in)
1999
45.2 mm (1.8 in)
2000
79.0 mm (3.1 in)
2001
77.6 mm (3.1 in)
2002
35.4 mm (1.4 in)
2003
61.9 mm (2.4 in)
2004
43.5 mm (1.7 in)
2005
65.0 mm (2.6 in)
2006
85.7 mm (3.4 in)
2007
35.8 mm (1.4 in)
2008
65.6 mm (2.6 in)
2009
78.3 mm (3.1 in)
2010
71.9 mm (2.8 in)
2011
40.8 mm (1.6 in)
Longest dry spell (CDD)
The longest dry spell of the year at Rosta, 1941 to 2011. The record is 52 days in 2003, marked on the chart; the median year is 24 days.
Longest dry spell (CDD) at Rosta by year
Year
Longest dry spell (CDD)
1941
n/a
1942
n/a
1943
8 days
1944
n/a
1945
14 days
1946
19 days
1947
26 days
1948
32 days
1949
19 days
1950
28 days
1951
32 days
1952
37 days
1953
27 days
1954
35 days
1955
21 days
1956
22 days
1957
19 days
1958
27 days
1959
23 days
1960
23 days
1961
19 days
1962
26 days
1963
26 days
1964
51 days
1965
28 days
1966
28 days
1967
20 days
1968
19 days
1969
29 days
1970
22 days
1971
21 days
1972
31 days
1973
18 days
1974
23 days
1975
22 days
1976
34 days
1977
22 days
1978
28 days
1979
26 days
1980
23 days
1981
25 days
1982
23 days
1983
32 days
1984
19 days
1985
16 days
1986
25 days
1987
21 days
1988
16 days
1989
17 days
1990
21 days
1991
23 days
1992
28 days
1993
25 days
1994
33 days
1995
19 days
1996
24 days
1997
23 days
1998
22 days
1999
21 days
2000
24 days
2001
16 days
2002
28 days
2003
52 days
2004
18 days
2005
16 days
2006
25 days
2007
30 days
2008
27 days
2009
26 days
2010
27 days
2011
26 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
71 years with a frost
Across 71 years with a frost, the median last spring frost at Rosta falls on 24 May and the median first autumn frost on 27 September, which leaves a median of 124 days between them.
In 1982 to 2011 the median growing season was 130 days. That is 13 days more than in 1941 to 1970.
Fitted over all years, the growing season changes by +4.7 days per decade at this station.
Frost dates and growing season at Rosta
Measure
Median, all years
Earliest period (1941 to 1970)
Recent period (1982 to 2011)
Recent against earliest
Fitted trend
Last spring frost
24 May
29 May
21 May
8 days earlier
-2.9 days per decade
First autumn frost
27 September
24 September
30 September
6 days later
+1.8 days per decade
Growing days
124 days
117 days
130 days
13 days more
+4.7 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
67 years, 1945 to 2011
A day with at least 28.0 mm (1.1 in) of rain is expected about once in 2 years. A day with at least 54.2 mm (2.1 in) of rain is expected about once in 100 years.
Rainfall return levels at Rosta: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
28.0 mm (1.1 in)
5 years
35.8 mm (1.4 in)
10 years
40.6 mm (1.6 in)
25 years
46.4 mm (1.8 in)
50 years
50.4 mm (2.0 in)
100 years
54.2 mm (2.1 in)
Longer than the 67 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, 67 years of values from 1945 to 2011.
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: 54.2 mm (2.1 in) in 2001; 52.4 mm (2.1 in) in 2009; 46.1 mm (1.8 in) in 2000.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Rosta, at 2006. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 2006 ran 0.2 C (0.3 F) lower than in the years before (possible change).
Suspected changes in the annual mean temperature at Rosta, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
2006
-0.2
-0.3
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 Rosta standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Rosta 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 2026-10-16 (16 October 2026). Records are computed by this site and are not official.