Record envelope, standing records and threshold days for Irwin 2 SE (USC00104588), Idaho, United States, with 52 years of record.
Key Facts for Irwin 2 SE
Irwin 2 SE (USC00104588) is a weather station in Idaho, United States at 43.40 latitude and -111.30 longitude, 1,617 m (5,305 ft) above sea level.
The station reports from 1909 to 1960, 52 years of record.
1,464 records set at Irwin 2 SE still stand.
Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
Irwin 2 SE tied a daily record high minimum temperature of 11.7 C (53.1 F) on 7 June 1960.
About the Station
Location: Idaho, United States, 43.40 latitude, -111.30 longitude.
Elevation: 1,617 m (5,305 ft).
Period of record: 1909 to 1960, 52 years.
Eligible elements: tmax, tmin, prcp, snow.
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 Irwin 2 SE. 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 Irwin 2 SE, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
14.4 C (57.9 F)
-41.7 C (-43.1 F)
n/a
n/a
Feb
15.0 C (59.0 F)
-42.8 C (-45.0 F)
n/a
n/a
Mar
18.9 C (66.0 F)
-33.3 C (-27.9 F)
n/a
n/a
Apr
27.8 C (82.0 F)
-20.6 C (-5.1 F)
n/a
n/a
May
32.2 C (90.0 F)
-11.1 C (12.0 F)
n/a
n/a
Jun
37.2 C (99.0 F)
-6.7 C (19.9 F)
n/a
n/a
Jul
38.9 C (102.0 F)
-3.3 C (26.1 F)
n/a
n/a
Aug
37.2 C (99.0 F)
-6.7 C (19.9 F)
n/a
n/a
Sep
34.4 C (93.9 F)
-12.8 C (9.0 F)
n/a
n/a
Oct
30.0 C (86.0 F)
-18.3 C (-0.9 F)
n/a
n/a
Nov
20.6 C (69.1 F)
-32.8 C (-27.0 F)
n/a
n/a
Dec
15.0 C (59.0 F)
-40.0 C (-40.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Irwin 2 SE still stand. 1925 holds the most, with 76.
Standing records at Irwin 2 SE by the year they were set
Year set
Standing records
1909
41
1910
66
1911
25
1912
9
1913
6
1914
25
1915
34
1916
30
1917
49
1918
35
1919
71
1920
22
1921
34
1922
26
1923
51
1924
35
1925
76
1926
40
1927
34
1928
18
1929
28
1930
27
1931
32
1932
30
1933
22
1934
55
1935
21
1936
23
1937
18
1938
12
1939
24
1940
19
1941
10
1942
19
1943
17
1944
7
1945
13
1946
18
1947
27
1948
31
1949
24
1950
32
1951
26
1952
20
1953
28
1954
27
1955
38
1956
21
1957
34
1958
13
1959
9
1960
12
Wettest Day of Each Month
Jan: 50.8 mm (2.0 in)
The wettest day on record for each calendar month at Irwin 2 SE. The most was 50.8 mm (2.0 in) on 31 January 1911.
Record daily precipitation for each month at Irwin 2 SE
Month
Record daily precipitation (mm)
Date
Jan
50.8 mm (2.0 in)
31 January 1911
Feb
22.1 mm (0.9 in)
2 February 1945
Mar
38.6 mm (1.5 in)
28 March 1928
Apr
34.0 mm (1.3 in)
15 April 1940
May
29.2 mm (1.1 in)
31 May 1936
Jun
35.8 mm (1.4 in)
5 June 1940
Jul
31.8 mm (1.3 in)
20 July 1922
Aug
43.2 mm (1.7 in)
1 August 1959
Sep
45.2 mm (1.8 in)
30 September 1926
Oct
27.9 mm (1.1 in)
17 October 1949
Nov
23.6 mm (0.9 in)
19 November 1942
Dec
40.6 mm (1.6 in)
12 December 1909
Period of Record Coverage
1909 to 1960
Complete yearUnder 90 percent of days
52 years of record at Irwin 2 SE, 1909 to 1960. 7 years have data for under 90 percent of days and are left out of rankings: 1909, 1911, 1912, 1913, 1917, 1935, 1960.
Cooler than the station meanWarmer than the station mean
One stripe for each of 40 complete years at Irwin 2 SE, 1910 to 1959. Blue stripes are years cooler than the station's own mean of 5.7 C (42.2 F); red stripes are warmer. The coolest year was 1923, at 2.5 C (36.5 F), and the warmest was 1934, at 7.9 C (46.2 F). The strongest colour marks a difference of 3.2 C (5.8 F).
Annual mean temperature at Irwin 2 SE as warming stripes, 1910 to 1959
Year
Annual mean temperature
Difference from the station mean
1910
6.8 C
+1.14 C
1915
5.3 C
-0.37 C
1918
5.6 C
-0.12 C
1919
4.3 C
-1.42 C
1920
4.3 C
-1.35 C
1921
5.2 C
-0.51 C
1923
2.5 C
-3.19 C
1924
3.3 C
-2.40 C
1925
2.8 C
-2.86 C
1926
5.0 C
-0.73 C
1927
5.7 C
+0.03 C
1928
5.2 C
-0.47 C
1929
4.9 C
-0.77 C
1931
5.8 C
+0.11 C
1932
4.5 C
-1.14 C
1933
6.0 C
+0.35 C
1934
7.9 C
+2.20 C
1936
5.6 C
-0.04 C
1937
5.8 C
+0.10 C
1938
6.1 C
+0.42 C
1939
6.4 C
+0.71 C
1940
6.9 C
+1.23 C
1941
6.1 C
+0.40 C
1942
4.9 C
-0.80 C
1943
5.9 C
+0.25 C
1944
5.0 C
-0.69 C
1945
5.7 C
-0.03 C
1946
6.5 C
+0.77 C
1947
6.5 C
+0.82 C
1948
5.9 C
+0.19 C
1949
6.3 C
+0.59 C
1950
6.5 C
+0.84 C
1951
5.8 C
+0.13 C
1952
6.2 C
+0.47 C
1953
7.3 C
+1.64 C
1954
7.1 C
+1.42 C
1956
6.0 C
+0.35 C
1957
6.3 C
+0.63 C
1958
7.1 C
+1.41 C
1959
6.4 C
+0.73 C
The annual mean temperature here has risen by 0.5 C (0.2 to 0.7) per decade over 1910 to 1959. In Fahrenheit: 0.8 F (0.4 to 1.3) per decade. The slope is a straight line fitted to 40 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Irwin 2 SE
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.5 C (0.2 to 0.7) per decade
0.8 F (0.4 to 1.3) per decade
1910 to 1959
40
Rise
Mean daily maximum
0.2 C (-0.1 to 0.6) per decade
0.4 F (-0.2 to 1.0) per decade
1910 to 1959
40
Not clearly different from zero
Mean daily minimum
0.7 C (0.4 to 1.0) per decade
1.3 F (0.8 to 1.8) per decade
1910 to 1959
40
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
1909 to 1960
Yearly extremes at Irwin 2 SE: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
38.9 C (102.0 F)
1931
33.9 C (93.0 F)
52
Coldest night (TNn)
-42.8 C (-45.0 F)
1933
-29.4 C (-20.9 F)
52
Wettest day (Rx1day)
50.8 mm (2.0 in)
1911
23.3 mm (0.9 in)
52
Wettest five days (Rx5day)
70.6 mm (2.8 in)
1943
40.2 mm (1.6 in)
52
Longest dry spell (CDD)
85 days
1935
31 days
52
Hottest day (TXx)
The hottest day of the year at Irwin 2 SE, 1909 to 1960. The record is 38.9 C (102.0 F) in 1931, marked on the chart; the median year is 33.9 C (93.0 F).
Hottest day (TXx) at Irwin 2 SE by year
Year
Hottest day (TXx)
1909
37.2 C (99.0 F)
1910
36.7 C (98.1 F)
1911
32.2 C (90.0 F)
1912
33.3 C (91.9 F)
1913
15.6 C (60.1 F)
1914
32.2 C (90.0 F)
1915
32.2 C (90.0 F)
1916
31.7 C (89.1 F)
1917
35.0 C (95.0 F)
1918
35.0 C (95.0 F)
1919
37.2 C (99.0 F)
1920
35.0 C (95.0 F)
1921
33.9 C (93.0 F)
1922
33.9 C (93.0 F)
1923
31.7 C (89.1 F)
1924
32.8 C (91.0 F)
1925
28.9 C (84.0 F)
1926
35.6 C (96.1 F)
1927
33.9 C (93.0 F)
1928
35.0 C (95.0 F)
1929
36.1 C (97.0 F)
1930
35.0 C (95.0 F)
1931
38.9 C (102.0 F)
1932
33.3 C (91.9 F)
1933
35.0 C (95.0 F)
1934
38.9 C (102.0 F)
1935
36.7 C (98.1 F)
1936
34.4 C (93.9 F)
1937
33.3 C (91.9 F)
1938
31.7 C (89.1 F)
1939
33.9 C (93.0 F)
1940
35.0 C (95.0 F)
1941
33.9 C (93.0 F)
1942
35.0 C (95.0 F)
1943
34.4 C (93.9 F)
1944
33.3 C (91.9 F)
1945
33.3 C (91.9 F)
1946
35.0 C (95.0 F)
1947
33.9 C (93.0 F)
1948
33.3 C (91.9 F)
1949
34.4 C (93.9 F)
1950
34.4 C (93.9 F)
1951
33.9 C (93.0 F)
1952
33.9 C (93.0 F)
1953
33.9 C (93.0 F)
1954
35.0 C (95.0 F)
1955
35.6 C (96.1 F)
1956
33.9 C (93.0 F)
1957
32.8 C (91.0 F)
1958
35.0 C (95.0 F)
1959
35.0 C (95.0 F)
1960
31.1 C (88.0 F)
Coldest night (TNn)
The coldest night of the year at Irwin 2 SE, 1909 to 1960. The record is -42.8 C (-45.0 F) in 1933, marked on the chart; the median year is -29.4 C (-20.9 F).
Coldest night (TNn) at Irwin 2 SE by year
Year
Coldest night (TNn)
1909
-37.8 C (-36.0 F)
1910
-29.4 C (-20.9 F)
1911
-28.9 C (-20.0 F)
1912
-37.8 C (-36.0 F)
1913
-20.6 C (-5.1 F)
1914
-30.6 C (-23.1 F)
1915
-34.4 C (-29.9 F)
1916
-31.1 C (-24.0 F)
1917
-41.7 C (-43.1 F)
1918
-33.9 C (-29.0 F)
1919
-40.0 C (-40.0 F)
1920
-31.1 C (-24.0 F)
1921
-35.0 C (-31.0 F)
1922
-40.0 C (-40.0 F)
1923
-33.9 C (-29.0 F)
1924
-36.7 C (-34.1 F)
1925
-22.2 C (-8.0 F)
1926
-26.7 C (-16.1 F)
1927
-35.0 C (-31.0 F)
1928
-26.7 C (-16.1 F)
1929
-35.0 C (-31.0 F)
1930
-36.7 C (-34.1 F)
1931
-26.7 C (-16.1 F)
1932
-31.1 C (-24.0 F)
1933
-42.8 C (-45.0 F)
1934
-24.4 C (-11.9 F)
1935
-31.7 C (-25.1 F)
1936
-31.1 C (-24.0 F)
1937
-37.2 C (-35.0 F)
1938
-21.7 C (-7.1 F)
1939
-23.9 C (-11.0 F)
1940
-26.1 C (-15.0 F)
1941
-25.0 C (-13.0 F)
1942
-32.8 C (-27.0 F)
1943
-27.8 C (-18.0 F)
1944
-24.4 C (-11.9 F)
1945
-29.4 C (-20.9 F)
1946
-23.3 C (-9.9 F)
1947
-22.8 C (-9.0 F)
1948
-27.8 C (-18.0 F)
1949
-32.8 C (-27.0 F)
1950
-26.7 C (-16.1 F)
1951
-29.4 C (-20.9 F)
1952
-27.2 C (-17.0 F)
1953
-21.7 C (-7.1 F)
1954
-23.9 C (-11.0 F)
1955
-27.8 C (-18.0 F)
1956
-33.9 C (-29.0 F)
1957
-28.3 C (-18.9 F)
1958
-22.2 C (-8.0 F)
1959
-26.1 C (-15.0 F)
1960
-27.8 C (-18.0 F)
Wettest day (Rx1day)
The wettest day of the year at Irwin 2 SE, 1909 to 1960. The record is 50.8 mm (2.0 in) in 1911, marked on the chart; the median year is 23.3 mm (0.9 in).
Wettest day (Rx1day) at Irwin 2 SE by year
Year
Wettest day (Rx1day)
1909
40.6 mm (1.6 in)
1910
20.3 mm (0.8 in)
1911
50.8 mm (2.0 in)
1912
25.4 mm (1.0 in)
1913
12.7 mm (0.5 in)
1914
29.5 mm (1.2 in)
1915
30.5 mm (1.2 in)
1916
32.0 mm (1.3 in)
1917
25.4 mm (1.0 in)
1918
23.6 mm (0.9 in)
1919
22.9 mm (0.9 in)
1920
17.8 mm (0.7 in)
1921
19.1 mm (0.8 in)
1922
31.8 mm (1.3 in)
1923
18.3 mm (0.7 in)
1924
15.5 mm (0.6 in)
1925
19.1 mm (0.8 in)
1926
45.2 mm (1.8 in)
1927
22.6 mm (0.9 in)
1928
38.6 mm (1.5 in)
1929
21.6 mm (0.9 in)
1930
21.1 mm (0.8 in)
1931
29.2 mm (1.1 in)
1932
33.8 mm (1.3 in)
1933
11.9 mm (0.5 in)
1934
16.5 mm (0.6 in)
1935
11.2 mm (0.4 in)
1936
29.2 mm (1.1 in)
1937
26.7 mm (1.1 in)
1938
22.9 mm (0.9 in)
1939
17.0 mm (0.7 in)
1940
35.8 mm (1.4 in)
1941
32.0 mm (1.3 in)
1942
23.6 mm (0.9 in)
1943
33.5 mm (1.3 in)
1944
20.6 mm (0.8 in)
1945
36.1 mm (1.4 in)
1946
21.1 mm (0.8 in)
1947
26.7 mm (1.1 in)
1948
25.1 mm (1.0 in)
1949
27.9 mm (1.1 in)
1950
26.4 mm (1.0 in)
1951
29.0 mm (1.1 in)
1952
20.8 mm (0.8 in)
1953
15.2 mm (0.6 in)
1954
21.8 mm (0.9 in)
1955
19.6 mm (0.8 in)
1956
16.8 mm (0.7 in)
1957
20.8 mm (0.8 in)
1958
20.1 mm (0.8 in)
1959
43.2 mm (1.7 in)
1960
15.2 mm (0.6 in)
Wettest five days (Rx5day)
The wettest five days of the year at Irwin 2 SE, 1909 to 1960. The record is 70.6 mm (2.8 in) in 1943, marked on the chart; the median year is 40.2 mm (1.6 in).
Wettest five days (Rx5day) at Irwin 2 SE by year
Year
Wettest five days (Rx5day)
1909
50.3 mm (2.0 in)
1910
22.9 mm (0.9 in)
1911
70.4 mm (2.8 in)
1912
43.3 mm (1.7 in)
1913
20.3 mm (0.8 in)
1914
58.0 mm (2.3 in)
1915
65.4 mm (2.6 in)
1916
46.2 mm (1.8 in)
1917
34.1 mm (1.3 in)
1918
38.7 mm (1.5 in)
1919
46.8 mm (1.8 in)
1920
34.7 mm (1.4 in)
1921
22.9 mm (0.9 in)
1922
47.0 mm (1.9 in)
1923
41.7 mm (1.6 in)
1924
20.5 mm (0.8 in)
1925
36.0 mm (1.4 in)
1926
45.2 mm (1.8 in)
1927
32.0 mm (1.3 in)
1928
46.7 mm (1.8 in)
1929
24.4 mm (1.0 in)
1930
30.5 mm (1.2 in)
1931
37.3 mm (1.5 in)
1932
33.8 mm (1.3 in)
1933
15.3 mm (0.6 in)
1934
25.4 mm (1.0 in)
1935
19.1 mm (0.8 in)
1936
53.1 mm (2.1 in)
1937
49.3 mm (1.9 in)
1938
45.4 mm (1.8 in)
1939
32.8 mm (1.3 in)
1940
52.3 mm (2.1 in)
1941
44.9 mm (1.8 in)
1942
46.7 mm (1.8 in)
1943
70.6 mm (2.8 in)
1944
55.6 mm (2.2 in)
1945
48.1 mm (1.9 in)
1946
38.1 mm (1.5 in)
1947
45.2 mm (1.8 in)
1948
69.6 mm (2.7 in)
1949
44.1 mm (1.7 in)
1950
38.1 mm (1.5 in)
1951
32.5 mm (1.3 in)
1952
42.0 mm (1.7 in)
1953
31.5 mm (1.2 in)
1954
37.6 mm (1.5 in)
1955
60.2 mm (2.4 in)
1956
26.4 mm (1.0 in)
1957
35.5 mm (1.4 in)
1958
36.3 mm (1.4 in)
1959
46.0 mm (1.8 in)
1960
27.4 mm (1.1 in)
Longest dry spell (CDD)
The longest dry spell of the year at Irwin 2 SE, 1909 to 1960. The record is 85 days in 1935, marked on the chart; the median year is 31 days.
Longest dry spell (CDD) at Irwin 2 SE by year
Year
Longest dry spell (CDD)
1909
18 days
1910
39 days
1911
18 days
1912
40 days
1913
30 days
1914
40 days
1915
24 days
1916
31 days
1917
44 days
1918
18 days
1919
57 days
1920
28 days
1921
27 days
1922
35 days
1923
54 days
1924
43 days
1925
18 days
1926
51 days
1927
25 days
1928
33 days
1929
30 days
1930
19 days
1931
46 days
1932
49 days
1933
42 days
1934
41 days
1935
85 days
1936
61 days
1937
29 days
1938
26 days
1939
44 days
1940
30 days
1941
28 days
1942
40 days
1943
36 days
1944
43 days
1945
19 days
1946
31 days
1947
30 days
1948
25 days
1949
48 days
1950
26 days
1951
30 days
1952
60 days
1953
28 days
1954
20 days
1955
23 days
1956
35 days
1957
19 days
1958
42 days
1959
25 days
1960
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
40 years with a frost
Across 40 years with a frost, the median last spring frost at Irwin 2 SE falls on 16 June and the median first autumn frost on 1 September, which leaves a median of 73 days between them.
Fitted over all years, the growing season changes by +12.2 days per decade at this station.
Frost dates and growing season at Irwin 2 SE
Measure
Median, all years
Earliest period
Recent period (1927 to 1959)
Recent against earliest
Fitted trend
Last spring frost
16 June
n/a
7 June
n/a
-4.1 days per decade
First autumn frost
1 September
n/a
9 September
n/a
+8.1 days per decade
Growing days
73 days
n/a
86 days
n/a
+12.2 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, 1910 to 1959
A day with at least 23.7 mm (0.9 in) of rain is expected about once in 2 years. A day with at least 49.1 mm (1.9 in) of rain is expected about once in 100 years.
Rainfall return levels at Irwin 2 SE: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
23.7 mm (0.9 in)
5 years
30.9 mm (1.2 in)
10 years
35.5 mm (1.4 in)
25 years
41.2 mm (1.6 in)
50 years
45.2 mm (1.8 in)
Longer than the 44 years of record
100 years
49.1 mm (1.9 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 1910 to 1959.
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: 45.2 mm (1.8 in) in 1926; 43.2 mm (1.7 in) in 1959; 38.6 mm (1.5 in) in 1928.
Station Changes
2 suspected
2 changes were suspected in the annual mean temperature of Irwin 2 SE, at 1927 and 1946. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1927 ran 1.2 C (2.2 F) higher than in the years before (likely change).
Relative to 5 neighbouring stations, the station's annual mean temperature from 1946 ran 0.4 C (0.7 F) higher than in the years before (possible change).
Suspected changes in the annual mean temperature at Irwin 2 SE, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1927
+1.2
+2.2
likely
5
1946
+0.4
+0.7
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 Irwin 2 SE standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Irwin 2 SE 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 2026-10-13 (13 October 2026). Records are computed by this site and are not official.