Porcupine 11 N Weather Records (USC00396736)

Record envelope, standing records and threshold days for Porcupine 11 N (USC00396736), South Dakota, United States, with 50 years of record.

Key Facts for Porcupine 11 N

Porcupine 11 N (USC00396736) is a weather station in South Dakota, United States at 43.40 latitude and -102.39 longitude, 860 m (2,820 ft) above sea level.
The station reports from 1963 to 2012, 50 years of record.
1,464 records set at Porcupine 11 N still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Porcupine 11 N set a daily record high maximum temperature of 31.7 C (89.1 F) on 25 April 2012.

About the Station

Location: South Dakota, United States, 43.40 latitude, -102.39 longitude.
Elevation: 860 m (2,820 ft).
Period of record: 1963 to 2012, 50 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.

Daily Record Envelope and 2026

0 days at or beyond a record

The band shows the record high and record low for each calendar day at Porcupine 11 N. 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 Porcupine 11 N, 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)	-36.1 C (-33.0 F)	n/a	n/a
Feb	22.8 C (73.0 F)	-42.2 C (-44.0 F)	n/a	n/a
Mar	30.6 C (87.1 F)	-35.6 C (-32.1 F)	n/a	n/a
Apr	35.0 C (95.0 F)	-17.8 C (0.0 F)	n/a	n/a
May	37.8 C (100.0 F)	-10.0 C (14.0 F)	n/a	n/a
Jun	42.8 C (109.0 F)	-3.3 C (26.1 F)	n/a	n/a
Jul	44.4 C (111.9 F)	1.7 C (35.1 F)	n/a	n/a
Aug	45.6 C (114.1 F)	0.6 C (33.1 F)	n/a	n/a
Sep	41.1 C (106.0 F)	-11.1 C (12.0 F)	n/a	n/a
Oct	36.1 C (97.0 F)	-23.9 C (-11.0 F)	n/a	n/a
Nov	29.4 C (84.9 F)	-30.0 C (-22.0 F)	n/a	n/a
Dec	21.1 C (70.0 F)	-43.9 C (-47.0 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at Porcupine 11 N still stand. 1985 holds the most, with 53.

Standing records at Porcupine 11 N by the year they were set
Year set	Standing records
1963	8
1964	23
1965	31
1966	32
1967	24
1968	24
1969	35
1970	24
1971	22
1972	35
1973	24
1974	33
1975	21
1976	42
1977	27
1978	31
1979	34
1980	27
1981	30
1982	19
1983	32
1984	27
1985	53
1986	31
1987	42
1988	40
1989	36
1990	39
1991	33
1992	39
1993	44
1994	31
1995	36
1996	47
1997	45
1998	27
1999	24
2000	13
2001	16
2002	36
2003	24
2004	25
2005	28
2006	30
2007	23
2008	15
2009	33
2010	14
2011	17
2012	18

Wettest Day of Each Month

May: 81.3 mm (3.2 in)

The wettest day on record for each calendar month at Porcupine 11 N. The most was 81.3 mm (3.2 in) on 14 May 1965.

Record daily precipitation for each month at Porcupine 11 N
Month	Record daily precipitation (mm)	Date
Jan	21.8 mm (0.9 in)	30 January 1971
Feb	21.8 mm (0.9 in)	26 February 2000
Mar	44.5 mm (1.8 in)	24 March 2009
Apr	53.6 mm (2.1 in)	19 April 2000
May	81.3 mm (3.2 in)	14 May 1965
Jun	75.4 mm (3.0 in)	18 June 1964
Jul	74.9 mm (2.9 in)	21 July 1976
Aug	46.7 mm (1.8 in)	16 August 1993
Sep	48.3 mm (1.9 in)	23 September 2006
Oct	55.9 mm (2.2 in)	5 October 1998
Nov	47.0 mm (1.9 in)	6 November 2008
Dec	20.3 mm (0.8 in)	17 December 1967

Period of Record Coverage

1963 to 2012

50 years of record at Porcupine 11 N, 1963 to 2012. 11 years have data for under 90 percent of days and are left out of rankings: 1963, 1964, 1965, 1988, 1989, 2000, 2001, 2002 and others.

Days with data per year at Porcupine 11 N
Year	Days with data	Share of year	Complete
1963	77	21%	No
1964	328	90%	No
1965	323	88%	No
1966	355	97%	Yes
1967	362	99%	Yes
1968	364	99%	Yes
1969	363	99%	Yes
1970	364	100%	Yes
1971	363	99%	Yes
1972	364	99%	Yes
1973	364	100%	Yes
1974	362	99%	Yes
1975	363	99%	Yes
1976	364	99%	Yes
1977	364	100%	Yes
1978	364	100%	Yes
1979	365	100%	Yes
1980	334	91%	Yes
1981	365	100%	Yes
1982	361	99%	Yes
1983	361	99%	Yes
1984	357	98%	Yes
1985	363	99%	Yes
1986	363	99%	Yes
1987	362	99%	Yes
1988	273	75%	No
1989	267	73%	No
1990	364	100%	Yes
1991	365	100%	Yes
1992	366	100%	Yes
1993	358	98%	Yes
1994	361	99%	Yes
1995	362	99%	Yes
1996	364	99%	Yes
1997	360	99%	Yes
1998	338	93%	Yes
1999	357	98%	Yes
2000	225	61%	No
2001	312	85%	No
2002	322	88%	No
2003	351	96%	Yes
2004	357	98%	Yes
2005	353	97%	Yes
2006	354	97%	Yes
2007	295	81%	No
2008	235	64%	No
2009	332	91%	Yes
2010	361	99%	Yes
2011	363	99%	Yes
2012	120	33%	No

Latest Records

Latest records at Porcupine 11 N
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
25 April 2012	Porcupine 11 N, US	daily high max	31.7 C (89.1 F)	1.7 C (3.1 F)	31 years	16 of 100 (Routine)
15 April 2012	Porcupine 11 N, US	daily rain	22.6 mm (0.9 in)	7.4 mm (0.29 in)	1 year	13 of 100 (Routine)
2 April 2012	Porcupine 11 N, US	daily high max	31.7 C (89.1 F)	2.8 C (5.0 F)	9 years	10 of 100 (Routine)
2 April 2012	Porcupine 11 N, US	daily high min	8.9 C (48.0 F)	1.1 C (2.0 F)	6 years	8 of 100 (Routine)
1 April 2012	Porcupine 11 N, US	daily high min	9.4 C (48.9 F)	3.3 C (5.9 F)	9 years	13 of 100 (Routine)
1 April 2012	Porcupine 11 N, US	daily high max	28.9 C (84.0 F)	1.1 C (2.0 F)	8 years	8 of 100 (Routine)
31 March 2012	Porcupine 11 N, US	daily high min (Tie)	7.2 C (45.0 F)	tie	46 years	4 of 100 (Routine)
27 March 2012	Porcupine 11 N, US	daily high max (Tie)	28.9 C (84.0 F)	tie	24 years	3 of 100 (Routine)
19 March 2012	Porcupine 11 N, US	daily high max	28.3 C (82.9 F)	2.2 C (4.0 F)	5 years	8 of 100 (Routine)
19 March 2012	Porcupine 11 N, US	daily high min (Tie)	3.9 C (39.0 F)	tie	36 years	3 of 100 (Routine)
18 March 2012	Porcupine 11 N, US	daily high max	27.2 C (81.0 F)	1.1 C (2.0 F)	40 years	18 of 100 (Routine)
17 March 2012	Porcupine 11 N, US	daily high max	28.3 C (82.9 F)	2.2 C (4.0 F)	18 years	12 of 100 (Routine)
16 March 2012	Porcupine 11 N, US	daily high min	7.2 C (45.0 F)	0.5 C (0.9 F)	17 years	10 of 100 (Routine)
14 March 2012	Porcupine 11 N, US	daily high max (Tie)	25.6 C (78.1 F)	tie	9 years	1 of 100 (Routine)
11 March 2012	Porcupine 11 N, US	daily high max	23.9 C (75.0 F)	1.1 C (2.0 F)	29 years	14 of 100 (Routine)
11 March 2012	Porcupine 11 N, US	daily high min	5.6 C (42.1 F)	0.6 C (1.1 F)	26 years	12 of 100 (Routine)
7 March 2012	Porcupine 11 N, US	daily high max	25.6 C (78.1 F)	5.0 C (9.0 F)	42 years	22 of 100 (Routine)
29 February 2012	Porcupine 11 N, US	daily snowfall	10.2 cm (4.0 in)	6.4 cm (2.5 in)	32 years	29 of 100 (Routine)
29 February 2012	Porcupine 11 N, US	daily snow depth	10.2 cm (4.0 in)	7.7 cm (3.0 in)	32 years	24 of 100 (Routine)
29 February 2012	Porcupine 11 N, US	daily rain	8.1 mm (0.32 in)	0.2 mm (0.01 in)	8 years	7 of 100 (Routine)

Climate Trend

36 complete years, 1966 to 2011

One stripe for each of 36 complete years at Porcupine 11 N, 1966 to 2011. Blue stripes are years cooler than the station's own mean of 8.5 C (47.3 F); red stripes are warmer. The coolest year was 1993, at 5.4 C (41.6 F), and the warmest was 1987, at 10.6 C (51.1 F). The strongest colour marks a difference of 3.2 C (5.8 F).

Annual mean temperature at Porcupine 11 N as warming stripes, 1966 to 2011
Year	Annual mean temperature	Difference from the station mean
1966	8.6 C	+0.16 C
1967	8.6 C	+0.16 C
1968	8.3 C	-0.17 C
1969	9.1 C	+0.64 C
1970	8.6 C	+0.11 C
1971	8.3 C	-0.15 C
1972	7.7 C	-0.82 C
1973	9.0 C	+0.49 C
1974	9.7 C	+1.21 C
1975	8.6 C	+0.17 C
1976	9.8 C	+1.32 C
1977	9.8 C	+1.32 C
1978	7.9 C	-0.54 C
1979	8.3 C	-0.15 C
1981	10.6 C	+2.10 C
1982	7.8 C	-0.67 C
1983	8.6 C	+0.16 C
1984	9.4 C	+0.91 C
1985	8.4 C	-0.06 C
1986	9.7 C	+1.27 C
1987	10.6 C	+2.15 C
1990	7.9 C	-0.60 C
1991	7.7 C	-0.78 C
1992	7.3 C	-1.18 C
1993	5.4 C	-3.11 C
1994	7.7 C	-0.82 C
1995	7.0 C	-1.46 C
1996	5.8 C	-2.70 C
1997	7.2 C	-1.24 C
1999	9.3 C	+0.83 C
2003	8.9 C	+0.41 C
2004	9.2 C	+0.76 C
2005	9.2 C	+0.72 C
2006	9.4 C	+0.90 C
2010	7.8 C	-0.72 C
2011	8.0 C	-0.49 C

The fitted trend in annual mean temperature here over 1966 to 2011 is -0.2 C (-0.5 to 0.1) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: -0.3 F (-0.9 to 0.2) per decade. The slope is a straight line fitted to 36 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Porcupine 11 N
Measure	Per decade (C)	Per decade (F)	Period	Complete years	Reading
Annual mean temperature	-0.2 C (-0.5 to 0.1) per decade	-0.3 F (-0.9 to 0.2) per decade	1966 to 2011	36	Not clearly different from zero
Mean daily maximum	-0.1 C (-0.4 to 0.2) per decade	-0.2 F (-0.7 to 0.4) per decade	1966 to 2011	36	Not clearly different from zero
Mean daily minimum	-0.29 C (-0.60 to 0.02) per decade	-0.53 F (-1.09 to 0.03) per decade	1966 to 2011	36	Not clearly different from zero

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

1963 to 2012

Yearly extremes at Porcupine 11 N: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	45.6 C (114.1 F)	1980	40.6 C (105.1 F)	50
Coldest night (TNn)	-43.9 C (-47.0 F)	1983	-31.7 C (-25.1 F)	50
Wettest day (Rx1day)	81.3 mm (3.2 in)	1965	40.1 mm (1.6 in)	50
Wettest five days (Rx5day)	123.4 mm (4.9 in)	1964	62.0 mm (2.4 in)	50
Longest dry spell (CDD)	80 days	1969	38 days	50

Hottest day (TXx)

The hottest day of the year at Porcupine 11 N, 1963 to 2012. The record is 45.6 C (114.1 F) in 1980, marked on the chart; the median year is 40.6 C (105.1 F).

Hottest day (TXx) at Porcupine 11 N by year
Year	Hottest day (TXx)
1963	34.4 C (93.9 F)
1964	41.7 C (107.1 F)
1965	39.4 C (102.9 F)
1966	41.7 C (107.1 F)
1967	38.3 C (100.9 F)
1968	38.3 C (100.9 F)
1969	41.1 C (106.0 F)
1970	42.2 C (108.0 F)
1971	41.1 C (106.0 F)
1972	39.4 C (102.9 F)
1973	43.3 C (109.9 F)
1974	42.8 C (109.0 F)
1975	44.4 C (111.9 F)
1976	41.7 C (107.1 F)
1977	42.2 C (108.0 F)
1978	42.2 C (108.0 F)
1979	42.2 C (108.0 F)
1980	45.6 C (114.1 F)
1981	40.6 C (105.1 F)
1982	41.7 C (107.1 F)
1983	40.6 C (105.1 F)
1984	40.0 C (104.0 F)
1985	43.3 C (109.9 F)
1986	40.0 C (104.0 F)
1987	42.8 C (109.0 F)
1988	41.7 C (107.1 F)
1989	41.7 C (107.1 F)
1990	43.3 C (109.9 F)
1991	39.4 C (102.9 F)
1992	38.3 C (100.9 F)
1993	35.0 C (95.0 F)
1994	38.9 C (102.0 F)
1995	40.6 C (105.1 F)
1996	38.3 C (100.9 F)
1997	36.1 C (97.0 F)
1998	40.6 C (105.1 F)
1999	37.2 C (99.0 F)
2000	39.4 C (102.9 F)
2001	38.3 C (100.9 F)
2002	41.1 C (106.0 F)
2003	42.2 C (108.0 F)
2004	40.0 C (104.0 F)
2005	41.1 C (106.0 F)
2006	42.8 C (109.0 F)
2007	41.7 C (107.1 F)
2008	37.8 C (100.0 F)
2009	37.8 C (100.0 F)
2010	40.0 C (104.0 F)
2011	39.4 C (102.9 F)
2012	31.7 C (89.1 F)

Coldest night (TNn)

The coldest night of the year at Porcupine 11 N, 1963 to 2012. The record is -43.9 C (-47.0 F) in 1983, marked on the chart; the median year is -31.7 C (-25.1 F).

Coldest night (TNn) at Porcupine 11 N by year
Year	Coldest night (TNn)
1963	-30.6 C (-23.1 F)
1964	-31.7 C (-25.1 F)
1965	-26.1 C (-15.0 F)
1966	-32.8 C (-27.0 F)
1967	-31.7 C (-25.1 F)
1968	-32.2 C (-26.0 F)
1969	-28.3 C (-18.9 F)
1970	-31.7 C (-25.1 F)
1971	-34.4 C (-29.9 F)
1972	-31.7 C (-25.1 F)
1973	-36.1 C (-33.0 F)
1974	-34.4 C (-29.9 F)
1975	-31.1 C (-24.0 F)
1976	-30.0 C (-22.0 F)
1977	-30.6 C (-23.1 F)
1978	-32.8 C (-27.0 F)
1979	-34.4 C (-29.9 F)
1980	-29.4 C (-20.9 F)
1981	-26.1 C (-15.0 F)
1982	-36.1 C (-33.0 F)
1983	-43.9 C (-47.0 F)
1984	-30.0 C (-22.0 F)
1985	-33.3 C (-27.9 F)
1986	-27.2 C (-17.0 F)
1987	-25.0 C (-13.0 F)
1988	-33.3 C (-27.9 F)
1989	-42.8 C (-45.0 F)
1990	-42.8 C (-45.0 F)
1991	-31.7 C (-25.1 F)
1992	-32.2 C (-26.0 F)
1993	-36.1 C (-33.0 F)
1994	-37.8 C (-36.0 F)
1995	-34.4 C (-29.9 F)
1996	-42.2 C (-44.0 F)
1997	-28.3 C (-18.9 F)
1998	-35.6 C (-32.1 F)
1999	-27.8 C (-18.0 F)
2000	-25.0 C (-13.0 F)
2001	-27.8 C (-18.0 F)
2002	-30.0 C (-22.0 F)
2003	-28.9 C (-20.0 F)
2004	-29.4 C (-20.9 F)
2005	-30.6 C (-23.1 F)
2006	-34.4 C (-29.9 F)
2007	-35.6 C (-32.1 F)
2008	-30.0 C (-22.0 F)
2009	-28.9 C (-20.0 F)
2010	-31.7 C (-25.1 F)
2011	-30.6 C (-23.1 F)
2012	-25.6 C (-14.1 F)

Wettest day (Rx1day)

The wettest day of the year at Porcupine 11 N, 1963 to 2012. The record is 81.3 mm (3.2 in) in 1965, marked on the chart; the median year is 40.1 mm (1.6 in).

Wettest day (Rx1day) at Porcupine 11 N by year
Year	Wettest day (Rx1day)
1963	12.7 mm (0.5 in)
1964	75.4 mm (3.0 in)
1965	81.3 mm (3.2 in)
1966	27.7 mm (1.1 in)
1967	52.3 mm (2.1 in)
1968	54.1 mm (2.1 in)
1969	27.9 mm (1.1 in)
1970	32.0 mm (1.3 in)
1971	28.4 mm (1.1 in)
1972	31.0 mm (1.2 in)
1973	31.8 mm (1.3 in)
1974	47.0 mm (1.9 in)
1975	50.8 mm (2.0 in)
1976	74.9 mm (2.9 in)
1977	59.9 mm (2.4 in)
1978	39.6 mm (1.6 in)
1979	55.6 mm (2.2 in)
1980	33.0 mm (1.3 in)
1981	29.7 mm (1.2 in)
1982	52.6 mm (2.1 in)
1983	53.1 mm (2.1 in)
1984	30.5 mm (1.2 in)
1985	31.0 mm (1.2 in)
1986	39.4 mm (1.6 in)
1987	30.5 mm (1.2 in)
1988	54.9 mm (2.2 in)
1989	38.1 mm (1.5 in)
1990	25.9 mm (1.0 in)
1991	36.6 mm (1.4 in)
1992	27.9 mm (1.1 in)
1993	46.7 mm (1.8 in)
1994	40.6 mm (1.6 in)
1995	33.0 mm (1.3 in)
1996	50.8 mm (2.0 in)
1997	47.0 mm (1.9 in)
1998	55.9 mm (2.2 in)
1999	34.5 mm (1.4 in)
2000	53.6 mm (2.1 in)
2001	35.3 mm (1.4 in)
2002	27.4 mm (1.1 in)
2003	31.8 mm (1.3 in)
2004	30.7 mm (1.2 in)
2005	41.7 mm (1.6 in)
2006	48.3 mm (1.9 in)
2007	40.6 mm (1.6 in)
2008	47.0 mm (1.9 in)
2009	44.5 mm (1.8 in)
2010	50.8 mm (2.0 in)
2011	57.9 mm (2.3 in)
2012	22.6 mm (0.9 in)

Wettest five days (Rx5day)

The wettest five days of the year at Porcupine 11 N, 1963 to 2012. The record is 123.4 mm (4.9 in) in 1964, marked on the chart; the median year is 62.0 mm (2.4 in).

Wettest five days (Rx5day) at Porcupine 11 N by year
Year	Wettest five days (Rx5day)
1963	17.0 mm (0.7 in)
1964	123.4 mm (4.9 in)
1965	102.9 mm (4.1 in)
1966	51.9 mm (2.0 in)
1967	104.8 mm (4.1 in)
1968	97.4 mm (3.8 in)
1969	59.4 mm (2.3 in)
1970	46.5 mm (1.8 in)
1971	62.7 mm (2.5 in)
1972	53.3 mm (2.1 in)
1973	55.6 mm (2.2 in)
1974	63.5 mm (2.5 in)
1975	61.7 mm (2.4 in)
1976	75.7 mm (3.0 in)
1977	60.7 mm (2.4 in)
1978	42.1 mm (1.7 in)
1979	55.6 mm (2.2 in)
1980	43.4 mm (1.7 in)
1981	34.3 mm (1.4 in)
1982	102.6 mm (4.0 in)
1983	82.1 mm (3.2 in)
1984	44.5 mm (1.8 in)
1985	59.5 mm (2.3 in)
1986	68.6 mm (2.7 in)
1987	48.0 mm (1.9 in)
1988	75.2 mm (3.0 in)
1989	41.0 mm (1.6 in)
1990	38.6 mm (1.5 in)
1991	74.3 mm (2.9 in)
1992	45.7 mm (1.8 in)
1993	65.5 mm (2.6 in)
1994	60.0 mm (2.4 in)
1995	71.8 mm (2.8 in)
1996	95.5 mm (3.8 in)
1997	60.2 mm (2.4 in)
1998	80.3 mm (3.2 in)
1999	70.6 mm (2.8 in)
2000	90.2 mm (3.6 in)
2001	65.3 mm (2.6 in)
2002	62.2 mm (2.4 in)
2003	50.3 mm (2.0 in)
2004	52.0 mm (2.0 in)
2005	79.3 mm (3.1 in)
2006	90.2 mm (3.6 in)
2007	63.5 mm (2.5 in)
2008	66.7 mm (2.6 in)
2009	50.3 mm (2.0 in)
2010	59.9 mm (2.4 in)
2011	69.1 mm (2.7 in)
2012	39.9 mm (1.6 in)

Longest dry spell (CDD)

The longest dry spell of the year at Porcupine 11 N, 1963 to 2012. The record is 80 days in 1969, marked on the chart; the median year is 38 days.

Longest dry spell (CDD) at Porcupine 11 N by year
Year	Longest dry spell (CDD)
1963	38 days
1964	41 days
1965	43 days
1966	24 days
1967	35 days
1968	55 days
1969	80 days
1970	65 days
1971	21 days
1972	39 days
1973	43 days
1974	60 days
1975	41 days
1976	50 days
1977	45 days
1978	35 days
1979	40 days
1980	44 days
1981	79 days
1982	35 days
1983	32 days
1984	31 days
1985	37 days
1986	31 days
1987	49 days
1988	41 days
1989	30 days
1990	38 days
1991	47 days
1992	33 days
1993	21 days
1994	30 days
1995	20 days
1996	31 days
1997	45 days
1998	51 days
1999	30 days
2000	25 days
2001	21 days
2002	40 days
2003	22 days
2004	24 days
2005	40 days
2006	28 days
2007	73 days
2008	27 days
2009	40 days
2010	28 days
2011	31 days
2012	35 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

36 years with a frost

Across 36 years with a frost, the median last spring frost at Porcupine 11 N falls on 17 May and the median first autumn frost on 19 September, which leaves a median of 126 days between them.

Fitted over all years, the growing season changes by -0.4 days per decade at this station.

Frost dates and growing season at Porcupine 11 N
Measure	Median, all years	Earliest period	Recent period (1972 to 2011)	Recent against earliest	Fitted trend
Last spring frost	17 May	n/a	16 May	n/a	0.0 days per decade
First autumn frost	19 September	n/a	18 September	n/a	-0.4 days per decade
Growing days	126 days	n/a	126 days	n/a	-0.4 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

41 years, 1965 to 2011

A day with at least 39.5 mm (1.6 in) of rain is expected about once in 2 years. A day with at least 87.4 mm (3.4 in) of rain is expected about once in 100 years.

Rainfall return levels at Porcupine 11 N: the daily rain expected about once in a given number of years
Expected about once in	A day with at least	Note
2 years	39.5 mm (1.6 in)
5 years	51.5 mm (2.0 in)
10 years	59.7 mm (2.4 in)
25 years	70.5 mm (2.8 in)
50 years	78.9 mm (3.1 in)	Longer than the 41 years of record
100 years	87.4 mm (3.4 in)	Longer than the 41 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, 41 years of values from 1965 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: 81.3 mm (3.2 in) in 1965; 74.9 mm (2.9 in) in 1976; 59.9 mm (2.4 in) in 1977.

Download the Data

Data for Porcupine 11 N standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Porcupine 11 N 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 2026-10-15 (15 October 2026). Records are computed by this site and are not official.

Data as of 2025-12-31. Last revised 31 December 2025 (2025-12-31).