Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Harmattan. 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 Harmattan, 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)
-46.1 C (-51.0 F)
n/a
n/a
Feb
18.9 C (66.0 F)
-45.6 C (-50.1 F)
n/a
n/a
Mar
20.0 C (68.0 F)
-42.2 C (-44.0 F)
n/a
n/a
Apr
27.8 C (82.0 F)
-34.4 C (-29.9 F)
n/a
n/a
May
31.1 C (88.0 F)
-13.3 C (8.1 F)
n/a
n/a
Jun
36.1 C (97.0 F)
-6.1 C (21.0 F)
n/a
n/a
Jul
34.4 C (93.9 F)
-2.8 C (27.0 F)
n/a
n/a
Aug
33.3 C (91.9 F)
-4.4 C (24.1 F)
n/a
n/a
Sep
30.6 C (87.1 F)
-16.7 C (1.9 F)
n/a
n/a
Oct
29.4 C (84.9 F)
-27.8 C (-18.0 F)
n/a
n/a
Nov
21.7 C (71.1 F)
-38.9 C (-38.0 F)
n/a
n/a
Dec
17.8 C (64.0 F)
-50.0 C (-58.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Harmattan still stand. 1936 holds the most, with 77.
Standing records at Harmattan by the year they were set
Year set
Standing records
1908
28
1909
25
1910
57
1911
56
1912
39
1913
49
1914
39
1915
38
1916
52
1917
54
1918
47
1919
66
1920
44
1921
49
1922
40
1923
47
1924
50
1925
46
1926
59
1927
31
1928
41
1929
49
1930
48
1931
54
1932
38
1933
41
1934
68
1935
49
1936
77
1937
39
1938
32
1939
12
Wettest Day of Each Month
Aug: 89.2 mm (3.5 in)
The wettest day on record for each calendar month at Harmattan. The most was 89.2 mm (3.5 in) on 19 August 1932.
Record daily precipitation for each month at Harmattan
Month
Record daily precipitation (mm)
Date
Jan
14.0 mm (0.6 in)
15 January 1920
Feb
15.2 mm (0.6 in)
4 February 1908
Mar
25.4 mm (1.0 in)
19 March 1937
Apr
35.6 mm (1.4 in)
20 April 1932
May
71.1 mm (2.8 in)
31 May 1923
Jun
72.1 mm (2.8 in)
6 June 1928
Jul
59.7 mm (2.4 in)
17 July 1915
Aug
89.2 mm (3.5 in)
19 August 1932
Sep
50.8 mm (2.0 in)
4 September 1916
Oct
30.5 mm (1.2 in)
3 October 1938
Nov
22.9 mm (0.9 in)
14 November 1914
Dec
18.8 mm (0.7 in)
4 December 1918
Period of Record Coverage
1908 to 1939
Complete yearUnder 90 percent of days
32 years of record at Harmattan, 1908 to 1939. 3 years have data for under 90 percent of days and are left out of rankings: 1909, 1919, 1939.
Cooler than the station meanWarmer than the station mean
One stripe for each of 24 complete years at Harmattan, 1910 to 1937. Blue stripes are years cooler than the station's own mean of 1.7 C (35.1 F); red stripes are warmer. The coolest year was 1927, at -0.1 C (31.8 F), and the warmest was 1934, at 3.3 C (38.0 F). The strongest colour marks a difference of 1.9 C (3.4 F).
Annual mean temperature at Harmattan as warming stripes, 1910 to 1937
Year
Annual mean temperature
Difference from the station mean
1910
2.4 C
+0.68 C
1912
2.4 C
+0.66 C
1913
1.4 C
-0.31 C
1914
1.8 C
+0.13 C
1915
3.1 C
+1.41 C
1916
0.1 C
-1.61 C
1917
0.7 C
-1.03 C
1918
2.0 C
+0.26 C
1921
1.0 C
-0.71 C
1922
0.7 C
-1.06 C
1923
2.3 C
+0.62 C
1924
1.5 C
-0.25 C
1925
1.7 C
+0.01 C
1926
2.5 C
+0.79 C
1927
-0.1 C
-1.80 C
1928
3.1 C
+1.36 C
1929
1.3 C
-0.37 C
1930
2.6 C
+0.88 C
1931
3.3 C
+1.59 C
1932
1.3 C
-0.43 C
1933
0.9 C
-0.79 C
1934
3.3 C
+1.63 C
1936
0.8 C
-0.96 C
1937
1.1 C
-0.65 C
This station does not have enough complete years (30 are needed) to fit a temperature trend.
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
1908 to 1939
Yearly extremes at Harmattan: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
36.1 C (97.0 F)
1937
31.1 C (88.0 F)
32
Coldest night (TNn)
-50.0 C (-58.0 F)
1924
-41.7 C (-43.1 F)
32
Wettest day (Rx1day)
89.2 mm (3.5 in)
1932
35.4 mm (1.4 in)
32
Wettest five days (Rx5day)
136.3 mm (5.4 in)
1928
62.7 mm (2.5 in)
32
Longest dry spell (CDD)
52 days
1931
30 days
32
Hottest day (TXx)
The hottest day of the year at Harmattan, 1908 to 1939. The record is 36.1 C (97.0 F) in 1937, marked on the chart; the median year is 31.1 C (88.0 F).
Hottest day (TXx) at Harmattan by year
Year
Hottest day (TXx)
1908
26.7 C (80.1 F)
1909
24.4 C (75.9 F)
1910
30.0 C (86.0 F)
1911
28.9 C (84.0 F)
1912
31.1 C (88.0 F)
1913
28.9 C (84.0 F)
1914
32.2 C (90.0 F)
1915
27.8 C (82.0 F)
1916
27.2 C (81.0 F)
1917
29.4 C (84.9 F)
1918
31.7 C (89.1 F)
1919
33.9 C (93.0 F)
1920
31.1 C (88.0 F)
1921
32.8 C (91.0 F)
1922
33.3 C (91.9 F)
1923
28.3 C (82.9 F)
1924
32.2 C (90.0 F)
1925
31.7 C (89.1 F)
1926
32.8 C (91.0 F)
1927
28.3 C (82.9 F)
1928
30.0 C (86.0 F)
1929
32.2 C (90.0 F)
1930
32.2 C (90.0 F)
1931
30.0 C (86.0 F)
1932
29.4 C (84.9 F)
1933
33.9 C (93.0 F)
1934
33.9 C (93.0 F)
1935
30.6 C (87.1 F)
1936
33.3 C (91.9 F)
1937
36.1 C (97.0 F)
1938
34.4 C (93.9 F)
1939
20.0 C (68.0 F)
Coldest night (TNn)
The coldest night of the year at Harmattan, 1908 to 1939. The record is -50.0 C (-58.0 F) in 1924, marked on the chart; the median year is -41.7 C (-43.1 F).
Coldest night (TNn) at Harmattan by year
Year
Coldest night (TNn)
1908
-33.3 C (-27.9 F)
1909
-45.6 C (-50.1 F)
1910
-41.7 C (-43.1 F)
1911
-44.4 C (-47.9 F)
1912
-35.6 C (-32.1 F)
1913
-38.9 C (-38.0 F)
1914
-42.2 C (-44.0 F)
1915
-33.3 C (-27.9 F)
1916
-46.1 C (-51.0 F)
1917
-45.6 C (-50.1 F)
1918
-40.6 C (-41.1 F)
1919
-41.7 C (-43.1 F)
1920
-45.0 C (-49.0 F)
1921
-42.2 C (-44.0 F)
1922
-40.0 C (-40.0 F)
1923
-45.0 C (-49.0 F)
1924
-50.0 C (-58.0 F)
1925
-36.7 C (-34.1 F)
1926
-35.6 C (-32.1 F)
1927
-43.3 C (-45.9 F)
1928
-41.1 C (-42.0 F)
1929
-46.1 C (-51.0 F)
1930
-43.3 C (-45.9 F)
1931
-33.3 C (-27.9 F)
1932
-42.8 C (-45.0 F)
1933
-37.8 C (-36.0 F)
1934
-40.0 C (-40.0 F)
1935
-42.8 C (-45.0 F)
1936
-45.6 C (-50.1 F)
1937
-41.1 C (-42.0 F)
1938
-37.8 C (-36.0 F)
1939
-36.7 C (-34.1 F)
Wettest day (Rx1day)
The wettest day of the year at Harmattan, 1908 to 1939. The record is 89.2 mm (3.5 in) in 1932, marked on the chart; the median year is 35.4 mm (1.4 in).
Wettest day (Rx1day) at Harmattan by year
Year
Wettest day (Rx1day)
1908
55.6 mm (2.2 in)
1909
63.5 mm (2.5 in)
1910
20.3 mm (0.8 in)
1911
36.8 mm (1.4 in)
1912
51.1 mm (2.0 in)
1913
30.0 mm (1.2 in)
1914
22.9 mm (0.9 in)
1915
59.7 mm (2.4 in)
1916
61.0 mm (2.4 in)
1917
40.6 mm (1.6 in)
1918
34.0 mm (1.3 in)
1919
40.4 mm (1.6 in)
1920
37.1 mm (1.5 in)
1921
21.8 mm (0.9 in)
1922
28.7 mm (1.1 in)
1923
71.1 mm (2.8 in)
1924
59.2 mm (2.3 in)
1925
32.5 mm (1.3 in)
1926
69.9 mm (2.8 in)
1927
53.8 mm (2.1 in)
1928
72.1 mm (2.8 in)
1929
31.8 mm (1.3 in)
1930
29.5 mm (1.2 in)
1931
54.4 mm (2.1 in)
1932
89.2 mm (3.5 in)
1933
20.3 mm (0.8 in)
1934
17.8 mm (0.7 in)
1935
31.8 mm (1.3 in)
1936
23.1 mm (0.9 in)
1937
31.8 mm (1.3 in)
1938
31.0 mm (1.2 in)
1939
17.8 mm (0.7 in)
Wettest five days (Rx5day)
The wettest five days of the year at Harmattan, 1908 to 1939. The record is 136.3 mm (5.4 in) in 1928, marked on the chart; the median year is 62.7 mm (2.5 in).
Wettest five days (Rx5day) at Harmattan by year
Year
Wettest five days (Rx5day)
1908
81.5 mm (3.2 in)
1909
88.9 mm (3.5 in)
1910
51.5 mm (2.0 in)
1911
77.4 mm (3.0 in)
1912
108.3 mm (4.3 in)
1913
73.9 mm (2.9 in)
1914
44.9 mm (1.8 in)
1915
133.1 mm (5.2 in)
1916
97.5 mm (3.8 in)
1917
70.5 mm (2.8 in)
1918
47.8 mm (1.9 in)
1919
41.3 mm (1.6 in)
1920
37.4 mm (1.5 in)
1921
33.1 mm (1.3 in)
1922
51.6 mm (2.0 in)
1923
120.1 mm (4.7 in)
1924
106.5 mm (4.2 in)
1925
74.1 mm (2.9 in)
1926
106.9 mm (4.2 in)
1927
62.7 mm (2.5 in)
1928
136.3 mm (5.4 in)
1929
48.1 mm (1.9 in)
1930
37.8 mm (1.5 in)
1931
97.3 mm (3.8 in)
1932
110.7 mm (4.4 in)
1933
42.9 mm (1.7 in)
1934
23.8 mm (0.9 in)
1935
41.9 mm (1.6 in)
1936
33.8 mm (1.3 in)
1937
47.8 mm (1.9 in)
1938
62.7 mm (2.5 in)
1939
17.8 mm (0.7 in)
Longest dry spell (CDD)
The longest dry spell of the year at Harmattan, 1908 to 1939. The record is 52 days in 1931, marked on the chart; the median year is 30 days.
Longest dry spell (CDD) at Harmattan by year
Year
Longest dry spell (CDD)
1908
39 days
1909
26 days
1910
24 days
1911
20 days
1912
33 days
1913
43 days
1914
27 days
1915
32 days
1916
28 days
1917
43 days
1918
20 days
1919
21 days
1920
39 days
1921
18 days
1922
32 days
1923
31 days
1924
28 days
1925
26 days
1926
32 days
1927
26 days
1928
45 days
1929
23 days
1930
30 days
1931
52 days
1932
17 days
1933
30 days
1934
35 days
1935
32 days
1936
17 days
1937
39 days
1938
36 days
1939
19 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
24 years with a frost
Across 24 years with a frost, the median last spring frost at Harmattan falls on 22 June and the median first autumn frost on 19 July, which leaves a median of 29 days between them.
Frost dates and growing season at Harmattan
Measure
Median, all years
Earliest period
Recent period (1910 to 1937)
Recent against earliest
Fitted trend
Last spring frost
22 June
n/a
22 June
n/a
n/a
First autumn frost
19 July
n/a
19 July
n/a
n/a
Growing days
29 days
n/a
29 days
n/a
n/a
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.
Download the Data
Data for Harmattan standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Harmattan 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.