Built 2026-10-19 (19 October 2026)

Harmattan Threshold Days by Year (CA003023055)

14 fixed thresholds counted per year at Harmattan (CA003023055): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Harmattan Thresholds

  • Harmattan: days with a maximum temperature at or below 0 C (32 F) in 29 years, most in 1937 with 98.
  • Harmattan: nights with a minimum temperature at or below 0 C (32 F) in 29 years, most in 1921 with 265.
  • Harmattan: nights with a minimum temperature at or below -10 C (14 F) in 29 years, most in 1922 with 138.
  • Harmattan: nights with a minimum temperature at or below -20 C (-4 F) in 29 years, most in 1936 with 74.
  • 14 fixed thresholds have at least one qualifying day at Harmattan.
20 years with a qualifying day
Days at or above 30 C (86 F) per year at Harmattan Days per year at Harmattan with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 15 in 1936. 0510151910: 21912: 11914: 61918: 51920: 21921: 21922: 31924: 21925: 41926: 61928: 21929: 91930: 21931: 11933: 81934: 101935: 31936: 151937: 31938: 51910191419201922192519281930193319351937
Days per year at Harmattan with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 15 in 1936.
Days at or above 30 C (86 F) per year at Harmattan
YearDaysDecade average
191023.5
191213.5
191463.5
191853.5
192023.8
192123.8
192233.8
192423.8
192543.8
192663.8
192823.8
192993.8
193025.9
193115.9
193385.9
1934105.9
193535.9
1936155.9
193735.9
193855.9
First to last qualifying date each year at Harmattan For each year, a bar from the first to the last day at Harmattan meeting 30 C (86 F). 1910: 14 July 1910 to 17 July 19101912: 27 June 1912 to 27 June 19121914: 4 July 1914 to 4 August 19141918: 17 July 1918 to 1 August 19181920: 17 July 1920 to 13 August 19201921: 20 July 1921 to 2 August 19211922: 3 June 1922 to 2 August 19221924: 1 July 1924 to 2 July 19241925: 11 July 1925 to 2 August 19251926: 26 June 1926 to 13 July 19261928: 25 May 1928 to 26 May 19281929: 2 July 1929 to 31 August 19291930: 12 July 1930 to 13 July 19301931: 22 July 1931 to 22 July 19311933: 13 June 1933 to 18 August 19331934: 28 May 1934 to 28 August 19341935: 14 July 1935 to 12 August 19351936: 27 May 1936 to 6 August 19361937: 28 June 1937 to 25 July 19371938: 22 July 1938 to 21 September 19381910191819221926193019341937JanFebMarAprMayJunJulAugSepOctNovDec
For each year, a bar from the first to the last day at Harmattan meeting 30 C (86 F).
First to last qualifying date each year at Harmattan
YearFirst dateLast date
19101910-07-141910-07-17
19121912-06-271912-06-27
19141914-07-041914-08-04
19181918-07-171918-08-01
19201920-07-171920-08-13
19211921-07-201921-08-02
19221922-06-031922-08-02
19241924-07-011924-07-02
19251925-07-111925-08-02
19261926-06-261926-07-13
19281928-05-251928-05-26
19291929-07-021929-08-31
19301930-07-121930-07-13
19311931-07-221931-07-22
19331933-06-131933-08-18
19341934-05-281934-08-28
19351935-07-141935-08-12
19361936-05-271936-08-06
19371937-06-281937-07-25
19381938-07-221938-09-21

Every Fixed Threshold

Fixed thresholds at Harmattan
ThresholdYears with a qualifying dayMost days in a yearYearLatest year days
30 C (86 F): Days201519365
35 C (95 F): Days1119371
90 F (32.2 C): Days12519331
0 C (32 F): Ice days (max2998193761
0 C (32 F): Frost days (min292651921220
-10 C (14 F): Days with min29138192298
-20 C (-4 F): Days with min2974193638
-30 C (-22 F): Days with min2934193612
-40 C (-40 F): Days with min20919362
10 mm (0.39 in): Days with 10 mm or more rain2922191512
25 mm (0.98 in): Days with 25 mm or more rain231019164
50 mm (1.97 in): Days with 50 mm or more rain11219161
10 cm (3.9 in): Days with 10 cm or more snowfall23719243
25 cm (9.8 in): Days with 25 cm or more snowfall2119321

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1910.

Download the Data

  • 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 2026-10-17 (17 October 2026). Threshold counts are computed by this site.

Data as of . Last revised (2026-10-17).