Zeona 10 SSW Weather Records (USC00399537)

Record envelope, standing records and threshold days for Zeona 10 SSW (USC00399537), South Dakota, United States, with 54 years of record.

Key Facts for Zeona 10 SSW

Zeona 10 SSW (USC00399537) is a weather station in South Dakota, United States at 45.07 latitude and -103.00 longitude, 832 m (2,730 ft) above sea level.
The station reports from 1949 to 2002, 54 years of record.
1,464 records set at Zeona 10 SSW still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Zeona 10 SSW set a monthly record high maximum temperature of 42.8 C (109.0 F) on 30 June 2002.

About the Station

Location: South Dakota, United States, 45.07 latitude, -103.00 longitude.
Elevation: 832 m (2,730 ft).
Period of record: 1949 to 2002, 54 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 Zeona 10 SSW. 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 Zeona 10 SSW, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	20.0 C (68.0 F)	-37.8 C (-36.0 F)	n/a	n/a
Feb	22.8 C (73.0 F)	-41.7 C (-43.1 F)	n/a	n/a
Mar	26.7 C (80.1 F)	-38.3 C (-36.9 F)	n/a	n/a
Apr	32.8 C (91.0 F)	-17.8 C (0.0 F)	n/a	n/a
May	36.7 C (98.1 F)	-11.7 C (10.9 F)	n/a	n/a
Jun	42.8 C (109.0 F)	-3.3 C (26.1 F)	n/a	n/a
Jul	43.3 C (109.9 F)	1.7 C (35.1 F)	n/a	n/a
Aug	42.2 C (108.0 F)	0.6 C (33.1 F)	n/a	n/a
Sep	41.1 C (106.0 F)	-7.8 C (18.0 F)	n/a	n/a
Oct	35.6 C (96.1 F)	-25.6 C (-14.1 F)	n/a	n/a
Nov	28.3 C (82.9 F)	-31.1 C (-24.0 F)	n/a	n/a
Dec	21.1 C (70.0 F)	-40.0 C (-40.0 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at Zeona 10 SSW still stand. 1988 holds the most, with 64.

Standing records at Zeona 10 SSW by the year they were set
Year set	Standing records
1953	23
1954	48
1955	44
1956	26
1957	24
1958	55
1959	9
1966	26
1967	32
1968	38
1969	35
1970	41
1971	17
1972	22
1974	2
1975	28
1976	27
1977	37
1978	27
1979	24
1980	32
1981	31
1982	19
1983	39
1984	30
1985	52
1986	39
1987	42
1988	64
1989	53
1990	53
1991	43
1992	56
1993	36
1994	31
1995	36
1996	36
1997	40
1998	34
1999	32
2000	31
2001	28
2002	22

All-Time Record Progression

2 new records

2 all-time records were set at Zeona 10 SSW between 30 June 1988 and 9 February 1994. Each dot is a new record.

When Zeona 10 SSW set new all-time records
Date	Kind	Detail
1988-06-30	Record daily precipitation	Record daily precipitation 92.2 mm (3.6 in)
1994-02-09	Record low minimum temperature	Record low minimum temperature -41.7 C (-43.1 F)

Wettest Day of Each Month

Jun: 92.2 mm (3.6 in)

The wettest day on record for each calendar month at Zeona 10 SSW. The most was 92.2 mm (3.6 in) on 30 June 1988.

Record daily precipitation for each month at Zeona 10 SSW
Month	Record daily precipitation (mm)	Date
Jan	29.7 mm (1.2 in)	4 January 1997
Feb	16.0 mm (0.6 in)	18 February 1991
Mar	57.7 mm (2.3 in)	11 March 1985
Apr	50.8 mm (2.0 in)	27 April 1984
May	62.7 mm (2.5 in)	22 May 1954
Jun	92.2 mm (3.6 in)	30 June 1988
Jul	88.4 mm (3.5 in)	21 July 1966
Aug	61.0 mm (2.4 in)	1 August 1996
Sep	45.0 mm (1.8 in)	20 September 1955
Oct	62.2 mm (2.4 in)	2 October 1971
Nov	35.6 mm (1.4 in)	1 November 2000
Dec	24.1 mm (0.9 in)	5 December 1983

Period of Record Coverage

1952 to 2002

44 years of record at Zeona 10 SSW, 1952 to 2002. 11 years have data for under 90 percent of days and are left out of rankings: 1952, 1959, 1966, 1970, 1971, 1972, 1974, 1979 and others.

Days with data per year at Zeona 10 SSW
Year	Days with data	Share of year	Complete
1952	61	17%	No
1953	358	98%	Yes
1954	356	98%	Yes
1955	360	99%	Yes
1956	351	96%	Yes
1957	355	97%	Yes
1958	361	99%	Yes
1959	119	33%	No
1966	214	59%	No
1967	364	100%	Yes
1968	358	98%	Yes
1969	338	93%	Yes
1970	309	85%	No
1971	223	61%	No
1972	267	73%	No
1974	68	19%	No
1975	363	99%	Yes
1976	365	100%	Yes
1977	360	99%	Yes
1978	361	99%	Yes
1979	302	83%	No
1980	275	75%	No
1981	358	98%	Yes
1982	364	100%	Yes
1983	364	100%	Yes
1984	362	99%	Yes
1985	362	99%	Yes
1986	364	100%	Yes
1987	364	100%	Yes
1988	366	100%	Yes
1989	363	99%	Yes
1990	362	99%	Yes
1991	361	99%	Yes
1992	364	99%	Yes
1993	304	83%	No
1994	365	100%	Yes
1995	365	100%	Yes
1996	365	100%	Yes
1997	365	100%	Yes
1998	365	100%	Yes
1999	365	100%	Yes
2000	336	92%	Yes
2001	364	100%	Yes
2002	180	49%	No

Latest Records

Latest records at Zeona 10 SSW
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
30 June 2002	Zeona 10 SSW, US	monthly high max	42.8 C (109.0 F)	1.7 C (3.1 F)	14 years	22 of 100 (Routine)
13 June 2002	Zeona 10 SSW, US	daily low min	-1.7 C (28.9 F)	1.7 C (3.1 F)	32 years	18 of 100 (Routine)
11 June 2002	Zeona 10 SSW, US	daily low min	2.8 C (37.0 F)	2.2 C (4.0 F)	44 years	23 of 100 (Routine)
5 June 2002	Zeona 10 SSW, US	daily low min	2.2 C (36.0 F)	1.1 C (2.0 F)	19 years	12 of 100 (Routine)
25 May 2002	Zeona 10 SSW, US	daily low min (Tie)	-0.6 C (30.9 F)	tie	7 years	1 of 100 (Routine)
24 May 2002	Zeona 10 SSW, US	daily low min	-5.6 C (21.9 F)	6.7 C (12.1 F)	0 years	19 of 100 (Routine)
24 May 2002	Zeona 10 SSW, US	daily low max	5.0 C (41.0 F)	5.0 C (9.0 F)	5 years	13 of 100 (Routine)
17 May 2002	Zeona 10 SSW, US	daily low max (Tie)	11.7 C (53.1 F)	tie	32 years	3 of 100 (Routine)
8 May 2002	Zeona 10 SSW, US	daily low max	3.9 C (39.0 F)	1.7 C (3.1 F)	16 years	11 of 100 (Routine)
7 May 2002	Zeona 10 SSW, US	daily low max	7.8 C (46.0 F)	1.6 C (2.9 F)	8 years	9 of 100 (Routine)
15 April 2002	Zeona 10 SSW, US	daily high min	6.7 C (44.1 F)	0.6 C (1.1 F)	25 years	13 of 100 (Routine)
15 April 2002	Zeona 10 SSW, US	daily high max (Tie)	27.2 C (81.0 F)	tie	16 years	2 of 100 (Routine)
3 April 2002	Zeona 10 SSW, US	daily low min	-15.0 C (5.0 F)	1.7 C (3.1 F)	48 years	22 of 100 (Routine)
3 April 2002	Zeona 10 SSW, US	daily low max	-4.4 C (24.1 F)	2.7 C (4.9 F)	3 years	8 of 100 (Routine)
22 March 2002	Zeona 10 SSW, US	daily low min	-20.6 C (-5.1 F)	4.5 C (8.1 F)	33 years	21 of 100 (Routine)
22 March 2002	Zeona 10 SSW, US	daily low max	-9.4 C (15.1 F)	7.7 C (13.9 F)	15 years	18 of 100 (Routine)
21 March 2002	Zeona 10 SSW, US	daily low min	-22.2 C (-8.0 F)	1.1 C (2.0 F)	12 years	9 of 100 (Routine)
21 March 2002	Zeona 10 SSW, US	daily low max (Tie)	-6.7 C (19.9 F)	tie	20 years	2 of 100 (Routine)
13 March 2002	Zeona 10 SSW, US	daily high max	18.3 C (64.9 F)	1.1 C (2.0 F)	19 years	11 of 100 (Routine)
10 March 2002	Zeona 10 SSW, US	daily low min	-21.7 C (-7.1 F)	1.7 C (3.1 F)	5 years	8 of 100 (Routine)

Climate Trend

32 complete years, 1953 to 2001

One stripe for each of 32 complete years at Zeona 10 SSW, 1953 to 2001. Blue stripes are years cooler than the station's own mean of 7.0 C (44.7 F); red stripes are warmer. The coolest year was 1996, at 4.6 C (40.3 F), and the warmest was 1987, at 8.8 C (47.8 F). The strongest colour marks a difference of 2.5 C (4.5 F).

Annual mean temperature at Zeona 10 SSW as warming stripes, 1953 to 2001
Year	Annual mean temperature	Difference from the station mean
1953	7.4 C	+0.32 C
1954	7.4 C	+0.33 C
1955	6.5 C	-0.54 C
1956	7.0 C	-0.03 C
1957	6.5 C	-0.55 C
1958	6.7 C	-0.33 C
1967	6.6 C	-0.46 C
1968	6.3 C	-0.72 C
1969	5.8 C	-1.20 C
1975	6.4 C	-0.60 C
1976	7.8 C	+0.73 C
1977	7.5 C	+0.43 C
1978	5.1 C	-1.90 C
1981	8.5 C	+1.41 C
1982	5.7 C	-1.33 C
1983	7.2 C	+0.17 C
1984	7.1 C	+0.01 C
1985	5.7 C	-1.35 C
1986	7.3 C	+0.28 C
1987	8.8 C	+1.73 C
1988	8.0 C	+0.91 C
1989	6.5 C	-0.56 C
1990	8.0 C	+0.96 C
1991	7.8 C	+0.79 C
1992	7.7 C	+0.64 C
1994	6.9 C	-0.16 C
1995	7.1 C	+0.06 C
1996	4.6 C	-2.43 C
1997	7.1 C	+0.03 C
1998	8.3 C	+1.24 C
1999	8.5 C	+1.43 C
2001	7.8 C	+0.77 C

The fitted trend in annual mean temperature here over 1953 to 2001 is 0.2 C (-0.1 to 0.4) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.3 F (-0.1 to 0.7) per decade. The slope is a straight line fitted to 32 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Zeona 10 SSW
Measure	Per decade (C)	Per decade (F)	Period	Complete years	Reading
Annual mean temperature	0.2 C (-0.1 to 0.4) per decade	0.3 F (-0.1 to 0.7) per decade	1953 to 2001	32	Not clearly different from zero
Mean daily maximum	-0.1 C (-0.4 to 0.2) per decade	-0.1 F (-0.7 to 0.4) per decade	1953 to 2001	32	Not clearly different from zero
Mean daily minimum	0.4 C (0.2 to 0.6) per decade	0.7 F (0.3 to 1.1) per decade	1953 to 2001	32	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

1949 to 2002

Yearly extremes at Zeona 10 SSW: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	43.3 C (109.9 F)	1981	40.0 C (104.0 F)	44
Coldest night (TNn)	-41.7 C (-43.1 F)	1994	-32.8 C (-27.0 F)	44
Wettest day (Rx1day)	92.2 mm (3.6 in)	1988	38.1 mm (1.5 in)	53
Wettest five days (Rx5day)	118.9 mm (4.7 in)	1988	59.7 mm (2.4 in)	53
Longest dry spell (CDD)	80 days	1952	39 days	53

Hottest day (TXx)

The hottest day of the year at Zeona 10 SSW, 1949 to 2002. The record is 43.3 C (109.9 F) in 1981, marked on the chart; the median year is 40.0 C (104.0 F).

Hottest day (TXx) at Zeona 10 SSW by year
Year	Hottest day (TXx)
1949	n/a
1950	n/a
1951	n/a
1952	22.2 C (72.0 F)
1953	38.3 C (100.9 F)
1954	40.0 C (104.0 F)
1955	39.4 C (102.9 F)
1956	38.9 C (102.0 F)
1957	40.6 C (105.1 F)
1958	41.7 C (107.1 F)
1959	29.4 C (84.9 F)
1960	n/a
1961	n/a
1962	n/a
1963	n/a
1964	n/a
1965	n/a
1966	40.6 C (105.1 F)
1967	38.3 C (100.9 F)
1968	37.8 C (100.0 F)
1969	40.0 C (104.0 F)
1970	40.6 C (105.1 F)
1971	40.6 C (105.1 F)
1972	39.4 C (102.9 F)
1974	21.1 C (70.0 F)
1975	42.2 C (108.0 F)
1976	40.0 C (104.0 F)
1977	40.6 C (105.1 F)
1978	41.1 C (106.0 F)
1979	37.8 C (100.0 F)
1980	41.1 C (106.0 F)
1981	43.3 C (109.9 F)
1982	37.2 C (99.0 F)
1983	39.4 C (102.9 F)
1984	39.4 C (102.9 F)
1985	41.1 C (106.0 F)
1986	40.6 C (105.1 F)
1987	40.6 C (105.1 F)
1988	41.1 C (106.0 F)
1989	42.8 C (109.0 F)
1990	41.7 C (107.1 F)
1991	40.0 C (104.0 F)
1992	37.2 C (99.0 F)
1993	34.4 C (93.9 F)
1994	38.9 C (102.0 F)
1995	38.9 C (102.0 F)
1996	36.7 C (98.1 F)
1997	38.3 C (100.9 F)
1998	40.6 C (105.1 F)
1999	41.1 C (106.0 F)
2000	40.6 C (105.1 F)
2001	41.7 C (107.1 F)
2002	42.8 C (109.0 F)

Coldest night (TNn)

The coldest night of the year at Zeona 10 SSW, 1949 to 2002. The record is -41.7 C (-43.1 F) in 1994, marked on the chart; the median year is -32.8 C (-27.0 F).

Coldest night (TNn) at Zeona 10 SSW by year
Year	Coldest night (TNn)
1949	n/a
1950	n/a
1951	n/a
1952	-22.8 C (-9.0 F)
1953	-27.2 C (-17.0 F)
1954	-37.2 C (-35.0 F)
1955	-28.9 C (-20.0 F)
1956	-32.2 C (-26.0 F)
1957	-33.3 C (-27.9 F)
1958	-34.4 C (-29.9 F)
1959	-34.4 C (-29.9 F)
1960	n/a
1961	n/a
1962	n/a
1963	n/a
1964	n/a
1965	n/a
1966	-30.0 C (-22.0 F)
1967	-32.8 C (-27.0 F)
1968	-33.9 C (-29.0 F)
1969	-35.0 C (-31.0 F)
1970	-37.8 C (-36.0 F)
1971	-33.9 C (-29.0 F)
1972	-36.1 C (-33.0 F)
1974	-19.4 C (-2.9 F)
1975	-32.2 C (-26.0 F)
1976	-35.0 C (-31.0 F)
1977	-32.8 C (-27.0 F)
1978	-33.9 C (-29.0 F)
1979	-33.9 C (-29.0 F)
1980	-31.1 C (-24.0 F)
1981	-28.9 C (-20.0 F)
1982	-34.4 C (-29.9 F)
1983	-36.7 C (-34.1 F)
1984	-30.0 C (-22.0 F)
1985	-33.9 C (-29.0 F)
1986	-31.1 C (-24.0 F)
1987	-21.7 C (-7.1 F)
1988	-35.6 C (-32.1 F)
1989	-40.0 C (-40.0 F)
1990	-38.3 C (-36.9 F)
1991	-31.7 C (-25.1 F)
1992	-27.2 C (-17.0 F)
1993	-31.7 C (-25.1 F)
1994	-41.7 C (-43.1 F)
1995	-30.0 C (-22.0 F)
1996	-36.7 C (-34.1 F)
1997	-32.2 C (-26.0 F)
1998	-38.3 C (-36.9 F)
1999	-28.9 C (-20.0 F)
2000	-30.0 C (-22.0 F)
2001	-29.4 C (-20.9 F)
2002	-27.2 C (-17.0 F)

Wettest day (Rx1day)

The wettest day of the year at Zeona 10 SSW, 1949 to 2002. The record is 92.2 mm (3.6 in) in 1988, marked on the chart; the median year is 38.1 mm (1.5 in).

Wettest day (Rx1day) at Zeona 10 SSW by year
Year	Wettest day (Rx1day)
1949	13.2 mm (0.5 in)
1950	38.1 mm (1.5 in)
1951	50.3 mm (2.0 in)
1952	29.2 mm (1.1 in)
1953	38.1 mm (1.5 in)
1954	62.7 mm (2.5 in)
1955	45.0 mm (1.8 in)
1956	35.6 mm (1.4 in)
1957	39.9 mm (1.6 in)
1958	25.4 mm (1.0 in)
1959	26.9 mm (1.1 in)
1960	49.5 mm (1.9 in)
1961	33.8 mm (1.3 in)
1962	39.4 mm (1.6 in)
1963	41.9 mm (1.6 in)
1964	48.8 mm (1.9 in)
1965	27.9 mm (1.1 in)
1966	88.4 mm (3.5 in)
1967	33.8 mm (1.3 in)
1968	31.2 mm (1.2 in)
1969	54.9 mm (2.2 in)
1970	43.7 mm (1.7 in)
1971	62.2 mm (2.4 in)
1972	56.6 mm (2.2 in)
1974	13.7 mm (0.5 in)
1975	46.7 mm (1.8 in)
1976	68.6 mm (2.7 in)
1977	31.2 mm (1.2 in)
1978	44.2 mm (1.7 in)
1979	27.9 mm (1.1 in)
1980	52.6 mm (2.1 in)
1981	34.5 mm (1.4 in)
1982	52.1 mm (2.1 in)
1983	44.5 mm (1.8 in)
1984	50.8 mm (2.0 in)
1985	57.7 mm (2.3 in)
1986	41.4 mm (1.6 in)
1987	29.0 mm (1.1 in)
1988	92.2 mm (3.6 in)
1989	41.7 mm (1.6 in)
1990	29.2 mm (1.1 in)
1991	36.6 mm (1.4 in)
1992	28.4 mm (1.1 in)
1993	30.7 mm (1.2 in)
1994	19.3 mm (0.8 in)
1995	45.7 mm (1.8 in)
1996	61.0 mm (2.4 in)
1997	30.5 mm (1.2 in)
1998	31.2 mm (1.2 in)
1999	36.8 mm (1.4 in)
2000	35.6 mm (1.4 in)
2001	21.6 mm (0.9 in)
2002	21.6 mm (0.9 in)

Wettest five days (Rx5day)

The wettest five days of the year at Zeona 10 SSW, 1949 to 2002. The record is 118.9 mm (4.7 in) in 1988, marked on the chart; the median year is 59.7 mm (2.4 in).

Wettest five days (Rx5day) at Zeona 10 SSW by year
Year	Wettest five days (Rx5day)
1949	20.8 mm (0.8 in)
1950	35.6 mm (1.4 in)
1951	56.1 mm (2.2 in)
1952	44.2 mm (1.7 in)
1953	49.0 mm (1.9 in)
1954	104.9 mm (4.1 in)
1955	55.2 mm (2.2 in)
1956	54.1 mm (2.1 in)
1957	49.8 mm (2.0 in)
1958	41.3 mm (1.6 in)
1959	48.2 mm (1.9 in)
1960	63.9 mm (2.5 in)
1961	34.3 mm (1.4 in)
1962	95.6 mm (3.8 in)
1963	53.3 mm (2.1 in)
1964	81.9 mm (3.2 in)
1965	57.1 mm (2.2 in)
1966	91.2 mm (3.6 in)
1967	57.9 mm (2.3 in)
1968	85.7 mm (3.4 in)
1969	88.7 mm (3.5 in)
1970	65.8 mm (2.6 in)
1971	63.5 mm (2.5 in)
1972	56.6 mm (2.2 in)
1974	14.8 mm (0.6 in)
1975	74.9 mm (2.9 in)
1976	91.7 mm (3.6 in)
1977	41.6 mm (1.6 in)
1978	52.1 mm (2.1 in)
1979	68.6 mm (2.7 in)
1980	69.9 mm (2.8 in)
1981	75.6 mm (3.0 in)
1982	91.7 mm (3.6 in)
1983	52.2 mm (2.1 in)
1984	103.5 mm (4.1 in)
1985	74.2 mm (2.9 in)
1986	70.6 mm (2.8 in)
1987	71.9 mm (2.8 in)
1988	118.9 mm (4.7 in)
1989	72.7 mm (2.9 in)
1990	36.1 mm (1.4 in)
1991	59.7 mm (2.4 in)
1992	54.6 mm (2.1 in)
1993	61.3 mm (2.4 in)
1994	37.4 mm (1.5 in)
1995	67.1 mm (2.6 in)
1996	115.9 mm (4.6 in)
1997	50.5 mm (2.0 in)
1998	53.0 mm (2.1 in)
1999	60.0 mm (2.4 in)
2000	69.9 mm (2.8 in)
2001	39.1 mm (1.5 in)
2002	22.4 mm (0.9 in)

Longest dry spell (CDD)

The longest dry spell of the year at Zeona 10 SSW, 1949 to 2002. The record is 80 days in 1952, marked on the chart; the median year is 39 days.

Longest dry spell (CDD) at Zeona 10 SSW by year
Year	Longest dry spell (CDD)
1949	51 days
1950	45 days
1951	37 days
1952	80 days
1953	43 days
1954	46 days
1955	30 days
1956	35 days
1957	45 days
1958	30 days
1959	47 days
1960	42 days
1961	30 days
1962	43 days
1963	30 days
1964	48 days
1965	42 days
1966	24 days
1967	40 days
1968	53 days
1969	35 days
1970	23 days
1971	24 days
1972	43 days
1974	30 days
1975	39 days
1976	42 days
1977	39 days
1978	35 days
1979	41 days
1980	33 days
1981	77 days
1982	22 days
1983	34 days
1984	64 days
1985	49 days
1986	31 days
1987	46 days
1988	40 days
1989	26 days
1990	62 days
1991	46 days
1992	64 days
1993	28 days
1994	34 days
1995	32 days
1996	20 days
1997	67 days
1998	26 days
1999	30 days
2000	28 days
2001	34 days
2002	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

32 years with a frost

Across 32 years with a frost, the median last spring frost at Zeona 10 SSW falls on 14 May and the median first autumn frost on 19 September, which leaves a median of 125 days between them.

Fitted over all years, the growing season changes by +3.9 days per decade at this station.

Frost dates and growing season at Zeona 10 SSW
Measure	Median, all years	Earliest period	Recent period (1955 to 2001)	Recent against earliest	Fitted trend
Last spring frost	14 May	n/a	13 May	n/a	-3.0 days per decade
First autumn frost	19 September	n/a	19 September	n/a	+0.9 days per decade
Growing days	125 days	n/a	127 days	n/a	+3.9 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

44 years, 1951 to 2001

A day with at least 38.9 mm (1.5 in) of rain is expected about once in 2 years. A day with at least 97.1 mm (3.8 in) of rain is expected about once in 100 years.

Rainfall return levels at Zeona 10 SSW: the daily rain expected about once in a given number of years
Expected about once in	A day with at least	Note
2 years	38.9 mm (1.5 in)
5 years	52.0 mm (2.0 in)
10 years	61.7 mm (2.4 in)
25 years	74.9 mm (2.9 in)
50 years	85.6 mm (3.4 in)	Longer than the 44 years of record
100 years	97.1 mm (3.8 in)	Longer than the 44 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, 44 years of values from 1951 to 2001.

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: 92.2 mm (3.6 in) in 1988; 88.4 mm (3.5 in) in 1966; 68.6 mm (2.7 in) in 1976.

Download the Data

Data for Zeona 10 SSW standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Zeona 10 SSW 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.

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