Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Porvoo Jernbole. 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 Porvoo Jernbole, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
7.8 C (46.0 F)
-38.0 C (-36.4 F)
n/a
n/a
Feb
9.8 C (49.6 F)
-38.0 C (-36.4 F)
n/a
n/a
Mar
15.2 C (59.4 F)
-33.0 C (-27.4 F)
n/a
n/a
Apr
24.0 C (75.2 F)
-22.0 C (-7.6 F)
n/a
n/a
May
29.1 C (84.4 F)
-7.3 C (18.9 F)
n/a
n/a
Jun
30.7 C (87.3 F)
-2.0 C (28.4 F)
n/a
n/a
Jul
32.5 C (90.5 F)
1.8 C (35.2 F)
n/a
n/a
Aug
31.7 C (89.1 F)
-3.0 C (26.6 F)
n/a
n/a
Sep
27.7 C (81.9 F)
-7.6 C (18.3 F)
n/a
n/a
Oct
18.8 C (65.8 F)
-16.5 C (2.3 F)
n/a
n/a
Nov
11.3 C (52.3 F)
-25.5 C (-13.9 F)
n/a
n/a
Dec
8.1 C (46.6 F)
-34.9 C (-30.8 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Porvoo Jernbole still stand. 2000 holds the most, with 59.
Standing records at Porvoo Jernbole by the year they were set
Year set
Standing records
1959
22
1960
13
1961
24
1962
30
1963
46
1964
20
1965
49
1966
47
1967
51
1968
47
1969
24
1970
19
1971
28
1972
27
1973
49
1974
18
1975
42
1976
21
1977
36
1978
43
1979
21
1980
26
1981
25
1982
32
1983
19
1984
20
1985
29
1986
20
1987
44
1988
31
1989
37
1990
33
1991
16
1992
41
1993
20
1994
17
1995
35
1996
18
1997
33
1998
34
1999
42
2000
59
2001
26
2002
46
2003
32
2004
17
2005
35
All-Time Record Progression
2 new records
2 all-time records were set at Porvoo Jernbole between 18 August 1991 and 29 July 1994. Each dot is a new record.
When Porvoo Jernbole set new all-time records
Date
Kind
Detail
1991-08-18
Record daily precipitation
Record daily precipitation 59.5 mm (2.3 in)
1994-07-29
Record high maximum temperature
Record high maximum temperature 32.5 C (90.5 F)
Wettest Day of Each Month
Aug: 59.5 mm (2.3 in)
The wettest day on record for each calendar month at Porvoo Jernbole. The most was 59.5 mm (2.3 in) on 18 August 1991.
Record daily precipitation for each month at Porvoo Jernbole
Month
Record daily precipitation (mm)
Date
Jan
19.5 mm (0.8 in)
13 January 1983
Feb
23.7 mm (0.9 in)
23 February 1999
Mar
16.0 mm (0.6 in)
21 March 1974
Apr
30.7 mm (1.2 in)
27 April 1962
May
30.6 mm (1.2 in)
14 May 1995
Jun
36.6 mm (1.4 in)
11 June 1998
Jul
55.0 mm (2.2 in)
25 July 1960
Aug
59.5 mm (2.3 in)
18 August 1991
Sep
39.7 mm (1.6 in)
12 September 1962
Oct
34.2 mm (1.3 in)
14 October 1992
Nov
24.9 mm (1.0 in)
30 November 1961
Dec
32.5 mm (1.3 in)
21 December 1984
Period of Record Coverage
1959 to 2005
Complete yearUnder 90 percent of days
47 years of record at Porvoo Jernbole, 1959 to 2005. 1 years have data for under 90 percent of days and are left out of rankings: 1959.
Cooler than the station meanWarmer than the station mean
One stripe for each of 45 complete years at Porvoo Jernbole, 1960 to 2005. Blue stripes are years cooler than the station's own mean of 4.3 C (39.8 F); red stripes are warmer. The coolest year was 1985, at 2.1 C (35.7 F), and the warmest was 2000, at 6.5 C (43.7 F). The strongest colour marks a difference of 2.3 C (4.1 F).
Annual mean temperature at Porvoo Jernbole as warming stripes, 1960 to 2005
Year
Annual mean temperature
Difference from the station mean
1960
3.7 C
-0.62 C
1961
5.3 C
+0.99 C
1962
3.2 C
-1.11 C
1963
3.0 C
-1.31 C
1964
4.0 C
-0.38 C
1965
3.4 C
-0.94 C
1966
2.5 C
-1.82 C
1967
4.0 C
-0.31 C
1968
3.4 C
-0.90 C
1969
2.8 C
-1.55 C
1970
3.0 C
-1.38 C
1971
4.0 C
-0.38 C
1972
4.8 C
+0.50 C
1973
4.1 C
-0.26 C
1974
5.7 C
+1.33 C
1975
5.8 C
+1.45 C
1976
2.7 C
-1.62 C
1977
3.7 C
-0.67 C
1978
2.7 C
-1.68 C
1979
3.7 C
-0.63 C
1980
3.3 C
-1.08 C
1982
4.1 C
-0.22 C
1983
4.8 C
+0.44 C
1984
4.7 C
+0.37 C
1985
2.1 C
-2.28 C
1986
3.8 C
-0.57 C
1987
2.2 C
-2.16 C
1988
4.9 C
+0.56 C
1989
6.3 C
+1.95 C
1990
5.8 C
+1.48 C
1991
5.3 C
+0.94 C
1992
5.4 C
+1.11 C
1993
4.5 C
+0.21 C
1994
4.4 C
+0.03 C
1995
5.3 C
+0.93 C
1996
4.1 C
-0.25 C
1997
5.1 C
+0.75 C
1998
4.6 C
+0.28 C
1999
5.5 C
+1.17 C
2000
6.5 C
+2.19 C
2001
5.3 C
+0.97 C
2002
5.4 C
+1.02 C
2003
5.1 C
+0.80 C
2004
5.3 C
+1.01 C
2005
5.9 C
+1.56 C
The annual mean temperature here has risen by 0.5 C (0.3 to 0.7) per decade over 1960 to 2005. In Fahrenheit: 0.8 F (0.5 to 1.2) 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 Porvoo Jernbole
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.5 C (0.3 to 0.7) per decade
0.8 F (0.5 to 1.2) per decade
1960 to 2005
45
Rise
Mean daily maximum
0.4 C (0.2 to 0.6) per decade
0.7 F (0.3 to 1.0) per decade
1960 to 2005
45
Rise
Mean daily minimum
0.6 C (0.3 to 0.8) per decade
1.0 F (0.6 to 1.5) per decade
1960 to 2005
45
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
1959 to 2005
Yearly extremes at Porvoo Jernbole: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
32.5 C (90.5 F)
1994
28.7 C (83.7 F)
47
Coldest night (TNn)
-38.0 C (-36.4 F)
1967
-30.1 C (-22.2 F)
47
Wettest day (Rx1day)
59.5 mm (2.3 in)
1991
30.0 mm (1.2 in)
47
Wettest five days (Rx5day)
108.5 mm (4.3 in)
2004
55.7 mm (2.2 in)
47
Longest dry spell (CDD)
42 days
1983
24 days
47
Hottest day (TXx)
The hottest day of the year at Porvoo Jernbole, 1959 to 2005. The record is 32.5 C (90.5 F) in 1994, marked on the chart; the median year is 28.7 C (83.7 F).
Hottest day (TXx) at Porvoo Jernbole by year
Year
Hottest day (TXx)
1959
30.3 C (86.5 F)
1960
28.4 C (83.1 F)
1961
27.7 C (81.9 F)
1962
24.0 C (75.2 F)
1963
29.9 C (85.8 F)
1964
29.3 C (84.7 F)
1965
27.2 C (81.0 F)
1966
29.1 C (84.4 F)
1967
29.3 C (84.7 F)
1968
28.6 C (83.5 F)
1969
29.2 C (84.6 F)
1970
27.7 C (81.9 F)
1971
27.2 C (81.0 F)
1972
30.7 C (87.3 F)
1973
32.3 C (90.1 F)
1974
24.8 C (76.6 F)
1975
31.7 C (89.1 F)
1976
26.0 C (78.8 F)
1977
29.9 C (85.8 F)
1978
27.5 C (81.5 F)
1979
28.0 C (82.4 F)
1980
30.5 C (86.9 F)
1981
26.5 C (79.7 F)
1982
28.4 C (83.1 F)
1983
30.0 C (86.0 F)
1984
26.7 C (80.1 F)
1985
27.6 C (81.7 F)
1986
29.5 C (85.1 F)
1987
27.5 C (81.5 F)
1988
30.4 C (86.7 F)
1989
28.5 C (83.3 F)
1990
25.5 C (77.9 F)
1991
28.0 C (82.4 F)
1992
30.1 C (86.2 F)
1993
28.5 C (83.3 F)
1994
32.5 C (90.5 F)
1995
29.6 C (85.3 F)
1996
26.6 C (79.9 F)
1997
30.0 C (86.0 F)
1998
27.6 C (81.7 F)
1999
31.1 C (88.0 F)
2000
29.7 C (85.5 F)
2001
28.5 C (83.3 F)
2002
28.7 C (83.7 F)
2003
31.2 C (88.2 F)
2004
29.0 C (84.2 F)
2005
30.0 C (86.0 F)
Coldest night (TNn)
The coldest night of the year at Porvoo Jernbole, 1959 to 2005. The record is -38.0 C (-36.4 F) in 1967, marked on the chart; the median year is -30.1 C (-22.2 F).
Coldest night (TNn) at Porvoo Jernbole by year
Year
Coldest night (TNn)
1959
-30.0 C (-22.0 F)
1960
-31.0 C (-23.8 F)
1961
-30.6 C (-23.1 F)
1962
-28.1 C (-18.6 F)
1963
-34.5 C (-30.1 F)
1964
-31.3 C (-24.3 F)
1965
-31.8 C (-25.2 F)
1966
-37.2 C (-35.0 F)
1967
-38.0 C (-36.4 F)
1968
-36.0 C (-32.8 F)
1969
-31.5 C (-24.7 F)
1970
-33.5 C (-28.3 F)
1971
-27.5 C (-17.5 F)
1972
-29.0 C (-20.2 F)
1973
-31.0 C (-23.8 F)
1974
-19.2 C (-2.6 F)
1975
-26.0 C (-14.8 F)
1976
-30.4 C (-22.7 F)
1977
-33.2 C (-27.8 F)
1978
-34.9 C (-30.8 F)
1979
-38.0 C (-36.4 F)
1980
-35.0 C (-31.0 F)
1981
-30.0 C (-22.0 F)
1982
-35.5 C (-31.9 F)
1983
-26.0 C (-14.8 F)
1984
-25.5 C (-13.9 F)
1985
-37.0 C (-34.6 F)
1986
-31.5 C (-24.7 F)
1987
-37.0 C (-34.6 F)
1988
-23.8 C (-10.8 F)
1989
-28.1 C (-18.6 F)
1990
-23.7 C (-10.7 F)
1991
-22.7 C (-8.9 F)
1992
-21.7 C (-7.1 F)
1993
-23.6 C (-10.5 F)
1994
-30.1 C (-22.2 F)
1995
-30.1 C (-22.2 F)
1996
-30.7 C (-23.3 F)
1997
-23.9 C (-11.0 F)
1998
-25.5 C (-13.9 F)
1999
-31.0 C (-23.8 F)
2000
-22.5 C (-8.5 F)
2001
-26.2 C (-15.2 F)
2002
-28.7 C (-19.7 F)
2003
-32.1 C (-25.8 F)
2004
-23.4 C (-10.1 F)
2005
-24.9 C (-12.8 F)
Wettest day (Rx1day)
The wettest day of the year at Porvoo Jernbole, 1959 to 2005. The record is 59.5 mm (2.3 in) in 1991, marked on the chart; the median year is 30.0 mm (1.2 in).
Wettest day (Rx1day) at Porvoo Jernbole by year
Year
Wettest day (Rx1day)
1959
35.3 mm (1.4 in)
1960
55.0 mm (2.2 in)
1961
38.8 mm (1.5 in)
1962
39.7 mm (1.6 in)
1963
41.3 mm (1.6 in)
1964
26.6 mm (1.0 in)
1965
23.5 mm (0.9 in)
1966
26.6 mm (1.0 in)
1967
28.0 mm (1.1 in)
1968
26.0 mm (1.0 in)
1969
30.0 mm (1.2 in)
1970
30.5 mm (1.2 in)
1971
19.8 mm (0.8 in)
1972
47.5 mm (1.9 in)
1973
32.7 mm (1.3 in)
1974
22.0 mm (0.9 in)
1975
18.2 mm (0.7 in)
1976
44.0 mm (1.7 in)
1977
26.6 mm (1.0 in)
1978
29.5 mm (1.2 in)
1979
41.0 mm (1.6 in)
1980
22.8 mm (0.9 in)
1981
22.5 mm (0.9 in)
1982
29.5 mm (1.2 in)
1983
38.3 mm (1.5 in)
1984
32.5 mm (1.3 in)
1985
19.3 mm (0.8 in)
1986
41.0 mm (1.6 in)
1987
27.5 mm (1.1 in)
1988
37.0 mm (1.5 in)
1989
20.5 mm (0.8 in)
1990
39.7 mm (1.6 in)
1991
59.5 mm (2.3 in)
1992
34.2 mm (1.3 in)
1993
46.8 mm (1.8 in)
1994
21.8 mm (0.9 in)
1995
30.6 mm (1.2 in)
1996
30.8 mm (1.2 in)
1997
19.4 mm (0.8 in)
1998
36.6 mm (1.4 in)
1999
24.5 mm (1.0 in)
2000
16.8 mm (0.7 in)
2001
28.3 mm (1.1 in)
2002
27.4 mm (1.1 in)
2003
27.6 mm (1.1 in)
2004
37.3 mm (1.5 in)
2005
32.2 mm (1.3 in)
Wettest five days (Rx5day)
The wettest five days of the year at Porvoo Jernbole, 1959 to 2005. The record is 108.5 mm (4.3 in) in 2004, marked on the chart; the median year is 55.7 mm (2.2 in).
Wettest five days (Rx5day) at Porvoo Jernbole by year
Year
Wettest five days (Rx5day)
1959
51.3 mm (2.0 in)
1960
67.8 mm (2.7 in)
1961
59.3 mm (2.3 in)
1962
63.6 mm (2.5 in)
1963
69.3 mm (2.7 in)
1964
36.8 mm (1.4 in)
1965
61.6 mm (2.4 in)
1966
45.1 mm (1.8 in)
1967
45.9 mm (1.8 in)
1968
40.4 mm (1.6 in)
1969
65.5 mm (2.6 in)
1970
76.2 mm (3.0 in)
1971
55.7 mm (2.2 in)
1972
66.2 mm (2.6 in)
1973
49.5 mm (1.9 in)
1974
58.9 mm (2.3 in)
1975
31.5 mm (1.2 in)
1976
63.9 mm (2.5 in)
1977
51.6 mm (2.0 in)
1978
57.5 mm (2.3 in)
1979
52.8 mm (2.1 in)
1980
47.4 mm (1.9 in)
1981
59.0 mm (2.3 in)
1982
58.0 mm (2.3 in)
1983
68.5 mm (2.7 in)
1984
58.0 mm (2.3 in)
1985
55.1 mm (2.2 in)
1986
56.6 mm (2.2 in)
1987
42.9 mm (1.7 in)
1988
42.8 mm (1.7 in)
1989
45.8 mm (1.8 in)
1990
71.1 mm (2.8 in)
1991
61.4 mm (2.4 in)
1992
69.7 mm (2.7 in)
1993
76.6 mm (3.0 in)
1994
54.4 mm (2.1 in)
1995
44.0 mm (1.7 in)
1996
55.2 mm (2.2 in)
1997
38.9 mm (1.5 in)
1998
53.5 mm (2.1 in)
1999
50.7 mm (2.0 in)
2000
43.7 mm (1.7 in)
2001
71.0 mm (2.8 in)
2002
60.1 mm (2.4 in)
2003
50.2 mm (2.0 in)
2004
108.5 mm (4.3 in)
2005
47.3 mm (1.9 in)
Longest dry spell (CDD)
The longest dry spell of the year at Porvoo Jernbole, 1959 to 2005. The record is 42 days in 1983, marked on the chart; the median year is 24 days.
Longest dry spell (CDD) at Porvoo Jernbole by year
Year
Longest dry spell (CDD)
1959
24 days
1960
35 days
1961
29 days
1962
17 days
1963
24 days
1964
28 days
1965
14 days
1966
19 days
1967
13 days
1968
19 days
1969
30 days
1970
15 days
1971
18 days
1972
38 days
1973
19 days
1974
25 days
1975
17 days
1976
24 days
1977
14 days
1978
31 days
1979
18 days
1980
24 days
1981
18 days
1982
22 days
1983
42 days
1984
31 days
1985
12 days
1986
24 days
1987
42 days
1988
16 days
1989
13 days
1990
25 days
1991
22 days
1992
32 days
1993
25 days
1994
37 days
1995
13 days
1996
25 days
1997
25 days
1998
15 days
1999
26 days
2000
31 days
2001
20 days
2002
33 days
2003
23 days
2004
13 days
2005
25 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
45 years with a frost
Across 45 years with a frost, the median last spring frost at Porvoo Jernbole falls on 25 May and the median first autumn frost on 15 September, which leaves a median of 110 days between them.
Fitted over all years, the growing season changes by +5.3 days per decade at this station.
Frost dates and growing season at Porvoo Jernbole
Measure
Median, all years
Earliest period
Recent period (1975 to 2005)
Recent against earliest
Fitted trend
Last spring frost
25 May
n/a
25 May
n/a
-2.6 days per decade
First autumn frost
15 September
n/a
17 September
n/a
+2.7 days per decade
Growing days
110 days
n/a
115 days
n/a
+5.3 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, 1959 to 2005
A day with at least 30.2 mm (1.2 in) of rain is expected about once in 2 years. A day with at least 61.1 mm (2.4 in) of rain is expected about once in 100 years.
Rainfall return levels at Porvoo Jernbole: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
30.2 mm (1.2 in)
5 years
38.9 mm (1.5 in)
10 years
44.5 mm (1.8 in)
25 years
51.4 mm (2.0 in)
50 years
56.3 mm (2.2 in)
Longer than the 47 years of record
100 years
61.1 mm (2.4 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 1959 to 2005.
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: 59.5 mm (2.3 in) in 1991; 55.0 mm (2.2 in) in 1960; 47.5 mm (1.9 in) in 1972.
Station Changes
2 suspected
2 changes were suspected in the annual mean temperature of Porvoo Jernbole, at 1979 and 1988. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1979 ran 0.1 C (0.3 F) lower than in the years before (possible change).
Relative to 5 neighbouring stations, the station's annual mean temperature from 1988 ran 0.3 C (0.5 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at Porvoo Jernbole, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1979
-0.1
-0.3
possible
5
1988
+0.3
+0.5
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 Porvoo Jernbole standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Porvoo Jernbole 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 2026-10-17 (17 October 2026). Records are computed by this site and are not official.