Record envelope, standing records and threshold days for Helena Wb City (USW00094104), Montana, United States, with 63 years of record.
Key Facts for Helena Wb City
Helena Wb City (USW00094104) is a weather station in Montana, United States at 46.58 latitude and -112.03 longitude, 1,263 m (4,144 ft) above sea level.
The station reports from 1893 to 1955, 63 years of record.
1,464 records set at Helena Wb City still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Helena Wb City set a daily record snowfall of 26.7 cm (10.5 in) on 27 November 1954.
About the Station
Location: Montana, United States, 46.58 latitude, -112.03 longitude.
Elevation: 1,263 m (4,144 ft).
Period of record: 1893 to 1955, 63 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.
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 Helena Wb City. 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 Helena Wb City, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
17.2 C (63.0 F)
-41.1 C (-42.0 F)
n/a
n/a
Feb
20.6 C (69.1 F)
-40.6 C (-41.1 F)
n/a
n/a
Mar
22.8 C (73.0 F)
-28.9 C (-20.0 F)
n/a
n/a
Apr
30.0 C (86.0 F)
-23.3 C (-9.9 F)
n/a
n/a
May
35.0 C (95.0 F)
-9.4 C (15.1 F)
n/a
n/a
Jun
38.9 C (102.0 F)
-0.6 C (30.9 F)
n/a
n/a
Jul
38.9 C (102.0 F)
2.2 C (36.0 F)
n/a
n/a
Aug
37.2 C (99.0 F)
-1.7 C (28.9 F)
n/a
n/a
Sep
33.3 C (91.9 F)
-14.4 C (6.1 F)
n/a
n/a
Oct
28.9 C (84.0 F)
-22.2 C (-8.0 F)
n/a
n/a
Nov
21.7 C (71.1 F)
-30.0 C (-22.0 F)
n/a
n/a
Dec
17.8 C (64.0 F)
-34.4 C (-29.9 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Helena Wb City still stand. 1919 holds the most, with 70.
Standing records at Helena Wb City by the year they were set
Year set
Standing records
1893
45
1894
33
1895
26
1896
62
1897
32
1898
28
1899
41
1900
45
1901
15
1902
16
1903
30
1904
22
1905
32
1906
33
1907
20
1908
19
1909
33
1910
39
1911
24
1912
18
1913
26
1914
13
1915
11
1916
48
1917
27
1918
55
1919
70
1920
16
1921
35
1922
19
1923
13
1924
40
1925
26
1926
29
1927
20
1928
23
1929
20
1930
26
1931
32
1932
31
1933
29
1934
31
1935
35
1936
67
1937
16
1938
10
1939
29
1940
3
1953
25
1954
26
All-Time Record Progression
1 new records
1 all-time records were set at Helena Wb City between 23 July 1936 and 23 July 1936. Each dot is a new record.
When Helena Wb City set new all-time records
Date
Kind
Detail
1936-07-23
Record high minimum temperature
Record high minimum temperature 23.3 C (73.9 F)
Wettest Day of Each Month
Jun: 54.9 mm (2.2 in)
The wettest day on record for each calendar month at Helena Wb City. The most was 54.9 mm (2.2 in) on 11 June 1915.
Record daily precipitation for each month at Helena Wb City
Month
Record daily precipitation (mm)
Date
Jan
15.7 mm (0.6 in)
27 January 1893
Feb
20.8 mm (0.8 in)
2 February 1895
Mar
19.8 mm (0.8 in)
20 March 1898
Apr
27.7 mm (1.1 in)
24 April 1900
May
50.8 mm (2.0 in)
12 May 1900
Jun
54.9 mm (2.2 in)
11 June 1915
Jul
32.5 mm (1.3 in)
1 July 1898
Aug
48.0 mm (1.9 in)
20 August 1933
Sep
41.4 mm (1.6 in)
30 September 1893
Oct
29.5 mm (1.2 in)
12 October 1920
Nov
33.0 mm (1.3 in)
25 November 1896
Dec
20.6 mm (0.8 in)
6 December 1901
Period of Record Coverage
1893 to 1955
Complete yearUnder 90 percent of days
52 years of record at Helena Wb City, 1893 to 1955. 3 years have data for under 90 percent of days and are left out of rankings: 1940, 1952, 1955.
Cooler than the station meanWarmer than the station mean
One stripe for each of 49 complete years at Helena Wb City, 1893 to 1954. Blue stripes are years cooler than the station's own mean of 6.7 C (44.0 F); red stripes are warmer. The coolest year was 1916, at 4.7 C (40.4 F), and the warmest was 1934, at 8.8 C (47.8 F). The strongest colour marks a difference of 2.1 C (3.8 F).
Annual mean temperature at Helena Wb City as warming stripes, 1893 to 1954
Year
Annual mean temperature
Difference from the station mean
1893
5.7 C
-0.96 C
1894
6.8 C
+0.14 C
1895
6.1 C
-0.58 C
1896
6.5 C
-0.19 C
1897
6.3 C
-0.42 C
1898
6.1 C
-0.60 C
1899
5.2 C
-1.49 C
1900
7.8 C
+1.11 C
1901
7.2 C
+0.55 C
1902
6.4 C
-0.29 C
1903
6.7 C
-0.01 C
1904
7.7 C
+1.03 C
1905
6.2 C
-0.50 C
1906
6.8 C
+0.13 C
1907
5.9 C
-0.81 C
1908
6.7 C
+0.00 C
1909
5.3 C
-1.36 C
1910
7.2 C
+0.52 C
1911
5.1 C
-1.63 C
1912
6.3 C
-0.43 C
1913
6.0 C
-0.65 C
1914
7.2 C
+0.55 C
1915
7.4 C
+0.75 C
1916
4.7 C
-2.04 C
1917
5.9 C
-0.75 C
1918
7.0 C
+0.30 C
1919
6.6 C
-0.13 C
1920
6.3 C
-0.42 C
1921
7.6 C
+0.88 C
1922
5.9 C
-0.79 C
1923
6.7 C
-0.01 C
1924
6.4 C
-0.33 C
1925
7.8 C
+1.13 C
1926
7.7 C
+1.05 C
1927
5.7 C
-1.02 C
1928
6.8 C
+0.15 C
1929
5.8 C
-0.85 C
1930
7.1 C
+0.42 C
1931
8.2 C
+1.52 C
1932
6.8 C
+0.10 C
1933
7.6 C
+0.94 C
1934
8.8 C
+2.08 C
1935
6.5 C
-0.23 C
1936
6.5 C
-0.23 C
1937
6.3 C
-0.42 C
1938
7.0 C
+0.34 C
1939
8.1 C
+1.37 C
1953
8.6 C
+1.90 C
1954
6.7 C
-0.01 C
The annual mean temperature here has risen by 0.2 C (0.1 to 0.4) per decade over 1893 to 1954. In Fahrenheit: 0.4 F (0.1 to 0.7) per decade. The slope is a straight line fitted to 49 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Helena Wb City
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.2 C (0.1 to 0.4) per decade
0.4 F (0.1 to 0.7) per decade
1893 to 1954
49
Rise
Mean daily maximum
0.3 C (0.1 to 0.5) per decade
0.6 F (0.3 to 0.8) per decade
1893 to 1954
49
Rise
Mean daily minimum
0.12 C (-0.05 to 0.28) per decade
0.2 F (-0.1 to 0.5) per decade
1893 to 1954
49
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
1893 to 1955
Yearly extremes at Helena Wb City: 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)
1893
35.0 C (95.0 F)
52
Coldest night (TNn)
-41.1 C (-42.0 F)
1893
-30.8 C (-23.5 F)
52
Wettest day (Rx1day)
54.9 mm (2.2 in)
1915
23.3 mm (0.9 in)
52
Wettest five days (Rx5day)
106.9 mm (4.2 in)
1908
43.0 mm (1.7 in)
52
Longest dry spell (CDD)
53 days
1904
32 days
52
Hottest day (TXx)
The hottest day of the year at Helena Wb City, 1893 to 1955. The record is 38.9 C (102.0 F) in 1893, marked on the chart; the median year is 35.0 C (95.0 F).
Hottest day (TXx) at Helena Wb City by year
Year
Hottest day (TXx)
1893
38.9 C (102.0 F)
1894
35.0 C (95.0 F)
1895
34.4 C (93.9 F)
1896
35.6 C (96.1 F)
1897
35.6 C (96.1 F)
1898
33.9 C (93.0 F)
1899
36.7 C (98.1 F)
1900
38.9 C (102.0 F)
1901
36.1 C (97.0 F)
1902
33.3 C (91.9 F)
1903
32.8 C (91.0 F)
1904
35.0 C (95.0 F)
1905
33.9 C (93.0 F)
1906
36.1 C (97.0 F)
1907
30.6 C (87.1 F)
1908
36.7 C (98.1 F)
1909
35.0 C (95.0 F)
1910
35.6 C (96.1 F)
1911
33.9 C (93.0 F)
1912
34.4 C (93.9 F)
1913
33.3 C (91.9 F)
1914
35.0 C (95.0 F)
1915
33.3 C (91.9 F)
1916
33.9 C (93.0 F)
1917
35.6 C (96.1 F)
1918
34.4 C (93.9 F)
1919
37.2 C (99.0 F)
1920
35.6 C (96.1 F)
1921
36.7 C (98.1 F)
1922
33.9 C (93.0 F)
1923
33.9 C (93.0 F)
1924
35.6 C (96.1 F)
1925
36.1 C (97.0 F)
1926
35.0 C (95.0 F)
1927
33.3 C (91.9 F)
1928
36.7 C (98.1 F)
1929
37.8 C (100.0 F)
1930
35.6 C (96.1 F)
1931
38.9 C (102.0 F)
1932
35.0 C (95.0 F)
1933
37.2 C (99.0 F)
1934
37.2 C (99.0 F)
1935
37.2 C (99.0 F)
1936
37.8 C (100.0 F)
1937
36.1 C (97.0 F)
1938
33.9 C (93.0 F)
1939
35.0 C (95.0 F)
1940
23.9 C (75.0 F)
1952
11.7 C (53.1 F)
1953
36.7 C (98.1 F)
1954
34.4 C (93.9 F)
1955
5.0 C (41.0 F)
Coldest night (TNn)
The coldest night of the year at Helena Wb City, 1893 to 1955. The record is -41.1 C (-42.0 F) in 1893, marked on the chart; the median year is -30.8 C (-23.5 F).
Coldest night (TNn) at Helena Wb City by year
Year
Coldest night (TNn)
1893
-41.1 C (-42.0 F)
1894
-32.2 C (-26.0 F)
1895
-27.2 C (-17.0 F)
1896
-30.0 C (-22.0 F)
1897
-31.1 C (-24.0 F)
1898
-26.7 C (-16.1 F)
1899
-34.4 C (-29.9 F)
1900
-30.6 C (-23.1 F)
1901
-24.4 C (-11.9 F)
1902
-31.1 C (-24.0 F)
1903
-26.7 C (-16.1 F)
1904
-22.8 C (-9.0 F)
1905
-34.4 C (-29.9 F)
1906
-28.9 C (-20.0 F)
1907
-29.4 C (-20.9 F)
1908
-25.6 C (-14.1 F)
1909
-34.4 C (-29.9 F)
1910
-33.9 C (-29.0 F)
1911
-32.8 C (-27.0 F)
1912
-27.8 C (-18.0 F)
1913
-27.2 C (-17.0 F)
1914
-32.2 C (-26.0 F)
1915
-23.9 C (-11.0 F)
1916
-35.6 C (-32.1 F)
1917
-31.7 C (-25.1 F)
1918
-33.9 C (-29.0 F)
1919
-33.3 C (-27.9 F)
1920
-28.9 C (-20.0 F)
1921
-27.2 C (-17.0 F)
1922
-30.6 C (-23.1 F)
1923
-34.4 C (-29.9 F)
1924
-34.4 C (-29.9 F)
1925
-17.8 C (0.0 F)
1926
-28.9 C (-20.0 F)
1927
-33.3 C (-27.9 F)
1928
-28.9 C (-20.0 F)
1929
-35.6 C (-32.1 F)
1930
-35.6 C (-32.1 F)
1931
-21.1 C (-6.0 F)
1932
-33.3 C (-27.9 F)
1933
-37.2 C (-35.0 F)
1934
-25.6 C (-14.1 F)
1935
-33.9 C (-29.0 F)
1936
-37.8 C (-36.0 F)
1937
-34.4 C (-29.9 F)
1938
-29.4 C (-20.9 F)
1939
-34.4 C (-29.9 F)
1940
-27.2 C (-17.0 F)
1952
-20.6 C (-5.1 F)
1953
-18.9 C (-2.0 F)
1954
-32.8 C (-27.0 F)
1955
-20.0 C (-4.0 F)
Wettest day (Rx1day)
The wettest day of the year at Helena Wb City, 1893 to 1955. The record is 54.9 mm (2.2 in) in 1915, marked on the chart; the median year is 23.3 mm (0.9 in).
Wettest day (Rx1day) at Helena Wb City by year
Year
Wettest day (Rx1day)
1893
41.4 mm (1.6 in)
1894
20.3 mm (0.8 in)
1895
20.8 mm (0.8 in)
1896
33.0 mm (1.3 in)
1897
19.1 mm (0.8 in)
1898
38.4 mm (1.5 in)
1899
19.3 mm (0.8 in)
1900
50.8 mm (2.0 in)
1901
40.4 mm (1.6 in)
1902
42.2 mm (1.7 in)
1903
12.7 mm (0.5 in)
1904
19.3 mm (0.8 in)
1905
28.4 mm (1.1 in)
1906
26.7 mm (1.1 in)
1907
46.2 mm (1.8 in)
1908
49.3 mm (1.9 in)
1909
30.2 mm (1.2 in)
1910
23.1 mm (0.9 in)
1911
38.6 mm (1.5 in)
1912
29.0 mm (1.1 in)
1913
18.3 mm (0.7 in)
1914
36.8 mm (1.4 in)
1915
54.9 mm (2.2 in)
1916
24.9 mm (1.0 in)
1917
19.8 mm (0.8 in)
1918
22.9 mm (0.9 in)
1919
13.7 mm (0.5 in)
1920
30.5 mm (1.2 in)
1921
19.6 mm (0.8 in)
1922
20.8 mm (0.8 in)
1923
23.4 mm (0.9 in)
1924
11.9 mm (0.5 in)
1925
24.4 mm (1.0 in)
1926
28.2 mm (1.1 in)
1927
38.4 mm (1.5 in)
1928
17.8 mm (0.7 in)
1929
17.5 mm (0.7 in)
1930
13.0 mm (0.5 in)
1931
15.2 mm (0.6 in)
1932
21.3 mm (0.8 in)
1933
48.0 mm (1.9 in)
1934
22.1 mm (0.9 in)
1935
14.2 mm (0.6 in)
1936
16.0 mm (0.6 in)
1937
33.0 mm (1.3 in)
1938
23.4 mm (0.9 in)
1939
16.5 mm (0.6 in)
1940
8.9 mm (0.35 in)
1952
17.5 mm (0.7 in)
1953
50.0 mm (2.0 in)
1954
33.0 mm (1.3 in)
1955
6.6 mm (0.26 in)
Wettest five days (Rx5day)
The wettest five days of the year at Helena Wb City, 1893 to 1955. The record is 106.9 mm (4.2 in) in 1908, marked on the chart; the median year is 43.0 mm (1.7 in).
Wettest five days (Rx5day) at Helena Wb City by year
Year
Wettest five days (Rx5day)
1893
52.8 mm (2.1 in)
1894
26.9 mm (1.1 in)
1895
41.4 mm (1.6 in)
1896
44.1 mm (1.7 in)
1897
38.4 mm (1.5 in)
1898
63.5 mm (2.5 in)
1899
30.6 mm (1.2 in)
1900
59.4 mm (2.3 in)
1901
48.6 mm (1.9 in)
1902
50.3 mm (2.0 in)
1903
30.3 mm (1.2 in)
1904
19.8 mm (0.8 in)
1905
36.8 mm (1.4 in)
1906
43.0 mm (1.7 in)
1907
95.2 mm (3.7 in)
1908
106.9 mm (4.2 in)
1909
60.6 mm (2.4 in)
1910
33.0 mm (1.3 in)
1911
52.3 mm (2.1 in)
1912
49.4 mm (1.9 in)
1913
34.2 mm (1.3 in)
1914
47.7 mm (1.9 in)
1915
63.6 mm (2.5 in)
1916
50.5 mm (2.0 in)
1917
47.5 mm (1.9 in)
1918
46.5 mm (1.8 in)
1919
18.2 mm (0.7 in)
1920
45.0 mm (1.8 in)
1921
30.8 mm (1.2 in)
1922
32.5 mm (1.3 in)
1923
35.9 mm (1.4 in)
1924
17.5 mm (0.7 in)
1925
40.1 mm (1.6 in)
1926
45.6 mm (1.8 in)
1927
80.7 mm (3.2 in)
1928
33.3 mm (1.3 in)
1929
44.3 mm (1.7 in)
1930
21.6 mm (0.9 in)
1931
26.9 mm (1.1 in)
1932
34.0 mm (1.3 in)
1933
75.0 mm (3.0 in)
1934
42.9 mm (1.7 in)
1935
17.2 mm (0.7 in)
1936
32.2 mm (1.3 in)
1937
47.4 mm (1.9 in)
1938
52.8 mm (2.1 in)
1939
32.0 mm (1.3 in)
1940
12.0 mm (0.5 in)
1952
22.1 mm (0.9 in)
1953
65.2 mm (2.6 in)
1954
62.0 mm (2.4 in)
1955
9.1 mm (0.36 in)
Longest dry spell (CDD)
The longest dry spell of the year at Helena Wb City, 1893 to 1955. The record is 53 days in 1904, marked on the chart; the median year is 32 days.
Longest dry spell (CDD) at Helena Wb City by year
Year
Longest dry spell (CDD)
1893
40 days
1894
21 days
1895
26 days
1896
26 days
1897
25 days
1898
35 days
1899
26 days
1900
37 days
1901
31 days
1902
26 days
1903
32 days
1904
53 days
1905
38 days
1906
26 days
1907
27 days
1908
27 days
1909
23 days
1910
33 days
1911
23 days
1912
24 days
1913
40 days
1914
32 days
1915
47 days
1916
24 days
1917
39 days
1918
39 days
1919
36 days
1920
17 days
1921
40 days
1922
32 days
1923
28 days
1924
23 days
1925
22 days
1926
30 days
1927
21 days
1928
44 days
1929
36 days
1930
47 days
1931
41 days
1932
37 days
1933
24 days
1934
46 days
1935
39 days
1936
23 days
1937
40 days
1938
34 days
1939
43 days
1940
13 days
1952
24 days
1953
48 days
1954
34 days
1955
29 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
49 years with a frost
Across 49 years with a frost, the median last spring frost at Helena Wb City falls on 10 May and the median first autumn frost on 24 September, which leaves a median of 139 days between them.
Fitted over all years, the growing season changes by +1.9 days per decade at this station.
Frost dates and growing season at Helena Wb City
Measure
Median, all years
Earliest period
Recent period (1912 to 1954)
Recent against earliest
Fitted trend
Last spring frost
10 May
n/a
9 May
n/a
-0.3 days per decade
First autumn frost
24 September
n/a
25 September
n/a
+1.6 days per decade
Growing days
139 days
n/a
140 days
n/a
+1.9 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
49 years, 1893 to 1954
A day with at least 25.4 mm (1.0 in) of rain is expected about once in 2 years. A day with at least 68.2 mm (2.7 in) of rain is expected about once in 100 years.
Rainfall return levels at Helena Wb City: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
25.4 mm (1.0 in)
5 years
36.2 mm (1.4 in)
10 years
43.6 mm (1.7 in)
25 years
53.2 mm (2.1 in)
50 years
60.7 mm (2.4 in)
Longer than the 49 years of record
100 years
68.2 mm (2.7 in)
Longer than the 49 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, 49 years of values from 1893 to 1954.
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: 54.9 mm (2.2 in) in 1915; 50.8 mm (2.0 in) in 1900; 50.0 mm (2.0 in) in 1953.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Helena Wb City, at 1934. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1934 ran 0.4 C (0.7 F) lower than in the years before (possible change).
Suspected changes in the annual mean temperature at Helena Wb City, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1934
-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 Helena Wb City standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Helena Wb City 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.