Weather Records on 18 August 1999

888 weather records were set or tied worldwide on 18 August 1999. Highest significance: Sedgwick 5 S, US.

Key Facts for 18 August 1999

On 18 August 1999, 888 weather records were set or tied at long-record stations worldwide.
386 were record highs and 200 were record lows, counting maximum and minimum temperature.
By timescale, 0 were all-time records, 19 monthly and 869 daily.
Sedgwick 5 S set a monthly record daily precipitation of 87.1 mm (3.4 in) on 18 August 1999.
Across 171 earlier years (1797 to 2026) the same calendar date averaged 438 records.

Record Map

888 stations

888 station records on 18 August 1999 are marked on the map, coloured by record type. Dot size shows the significance score. Made with Natural Earth.

Weather records on 18 August 1999: highest significance records shown on the map
Station	Country	Type	Value	Significance
Sedgwick 5 S	United States	Record daily precipitation	87.1 mm (3.4 in)	65 of 100 (Major)
Wongan Hills	Australia	Record daily precipitation	30.7 mm (1.2 in)	63 of 100 (Major)
Lake Hinds	Australia	Record daily precipitation	33.4 mm (1.3 in)	61 of 100 (Major)
Hoogwoud	Netherlands	Record daily precipitation	30.9 mm (1.2 in)	59 of 100 (Notable)
Goomalling	Australia	Record daily precipitation	27.4 mm (1.1 in)	58 of 100 (Notable)
Mindalla	Australia	Record daily precipitation	28.2 mm (1.1 in)	56 of 100 (Notable)
Rustefjelbma	Norway	Record daily precipitation	35.2 mm (1.4 in)	56 of 100 (Notable)
Fort Hill	Australia	Record daily precipitation	26.0 mm (1.0 in)	52 of 100 (Notable)
Postville	United States	Record daily precipitation	50.8 mm (2.0 in)	52 of 100 (Notable)
Myakka Rvr Sp	United States	Record daily precipitation	101.6 mm (4.0 in)	49 of 100 (Notable)
Colquitt 2 W	United States	Record daily precipitation	82.0 mm (3.2 in)	49 of 100 (Notable)
San Pedro	Mexico	Record daily precipitation	83.3 mm (3.3 in)	48 of 100 (Notable)
Strawberry North	Australia	Record daily precipitation	27.0 mm (1.1 in)	47 of 100 (Notable)
Velikie Luki	Russia	Record daily precipitation	26.6 mm (1.0 in)	47 of 100 (Notable)
Buracica	Brazil	Record daily precipitation	60.3 mm (2.4 in)	46 of 100 (Notable)
Wijk_Aan_Zee_1	Netherlands	Record daily precipitation	38.7 mm (1.5 in)	46 of 100 (Notable)
Monticello	United States	Record high minimum temperature	26.7 C (80.1 F)	46 of 100 (Notable)
Poplarville Exp STN	United States	Record high maximum temperature	38.3 C (100.9 F)	46 of 100 (Notable)
Ygoola	Australia	Record daily precipitation	25.0 mm (1.0 in)	45 of 100 (Notable)
Zverinogolovskaja	Russia	Record daily precipitation	27.9 mm (1.1 in)	45 of 100 (Notable)
Kearney 4 NE	United States	Record daily precipitation	52.3 mm (2.1 in)	45 of 100 (Notable)
Moora	Australia	Record daily precipitation	46.0 mm (1.8 in)	44 of 100 (Notable)
Teodoro Sampaio	Brazil	Record daily precipitation	44.5 mm (1.8 in)	44 of 100 (Notable)
Barabinsk	Russia	Record high minimum temperature	19.9 C (67.8 F)	43 of 100 (Notable)
Aalsmeer	Netherlands	Record daily precipitation	32.6 mm (1.3 in)	42 of 100 (Notable)
Ponyri	Russia	Record daily precipitation	42.7 mm (1.7 in)	42 of 100 (Notable)
Osceola	United States	Record daily precipitation	38.4 mm (1.5 in)	41 of 100 (Notable)
Benkelman 1N	United States	Record daily precipitation	54.9 mm (2.2 in)	41 of 100 (Notable)
Trenton Dam 1N	United States	Record daily precipitation	44.2 mm (1.7 in)	41 of 100 (Notable)
Manston	United Kingdom	Record daily precipitation	25.1 mm (1.0 in)	40 of 100 (Notable)
Waverly	United States	Record high maximum temperature	34.4 C (93.9 F)	40 of 100 (Notable)
Newberry	United States	Record high maximum temperature	38.9 C (102.0 F)	40 of 100 (Notable)
Seward	United States	Record daily precipitation	57.2 mm (2.3 in)	39 of 100 (Notable)
Port Lincoln	Australia	Record high maximum temperature	25.7 C (78.3 F)	38 of 100 (Notable)
Presa Taxhimay	Mexico	Record high minimum temperature	17.8 C (64.0 F)	38 of 100 (Notable)
Chipley	United States	Record daily precipitation	54.4 mm (2.1 in)	38 of 100 (Notable)
Grace	United States	Record high maximum temperature	35.0 C (95.0 F)	38 of 100 (Notable)
Minden	United States	Record daily precipitation	54.1 mm (2.1 in)	38 of 100 (Notable)
Valga	Estonia	Record daily precipitation	30.8 mm (1.2 in)	37 of 100 (Notable)
Hoek_van_Holland_1	Netherlands	Record daily precipitation	25.4 mm (1.0 in)	37 of 100 (Notable)
Yuanping	China	Record daily precipitation	68.4 mm (2.7 in)	36 of 100 (Notable)
Tangancicuaro	Mexico	Record high maximum temperature	35.6 C (96.1 F)	36 of 100 (Notable)
Beverwijk	Netherlands	Record daily precipitation	38.0 mm (1.5 in)	36 of 100 (Notable)
Atlanta 2 WNW	United States	Record daily precipitation	49.8 mm (2.0 in)	36 of 100 (Notable)
Bertrand	United States	Record daily precipitation	38.6 mm (1.5 in)	35 of 100 (Notable)
Nuuk	Greenland [Denmark]	Record daily precipitation	63.0 mm (2.5 in)	34 of 100 (Routine)
Apuka	Russia	Record daily precipitation	31.6 mm (1.2 in)	34 of 100 (Routine)
Omsk	Russia	Record high maximum temperature	35.2 C (95.4 F)	34 of 100 (Routine)
Mc Cook	United States	Record daily precipitation	35.8 mm (1.4 in)	34 of 100 (Routine)
Newington	Australia	Record daily precipitation	25.0 mm (1.0 in)	33 of 100 (Routine)
Wangerooge	Germany	Record daily precipitation	31.4 mm (1.2 in)	33 of 100 (Routine)
Palizada	Mexico	Record low maximum temperature	27.8 C (82.0 F)	33 of 100 (Routine)
Huahuaxtla (Cfe)	Mexico	Record daily precipitation	50.8 mm (2.0 in)	33 of 100 (Routine)
Nachiki	Russia	Record daily precipitation	39.0 mm (1.5 in)	33 of 100 (Routine)
Duolun	China	Record daily precipitation	38.7 mm (1.5 in)	32 of 100 (Routine)
Sotuta (Dge)	Mexico	Record daily precipitation	45.0 mm (1.8 in)	32 of 100 (Routine)
Heber (Black Mesa) Rs	United States	Record daily precipitation	60.7 mm (2.4 in)	32 of 100 (Routine)
Boone	United States	Record daily precipitation	77.0 mm (3.0 in)	32 of 100 (Routine)
Siliguri	India	Record daily precipitation	109.0 mm (4.3 in)	31 of 100 (Routine)
La Tinaja	Mexico	Record high maximum temperature	31.7 C (89.1 F)	31 of 100 (Routine)

Counts by Type and Timescale

888 records

Records set or tied on 18 August 1999 by type: Highest daily maximum 231, Lowest daily maximum 83, Highest daily minimum 155, Lowest daily minimum 117, Heaviest daily rainfall 302.

Records on 18 August 1999 by type
Record type	Records
Highest daily maximum	231
Lowest daily maximum	83
Highest daily minimum	155
Lowest daily minimum	117
Heaviest daily rainfall	302
Heaviest daily snowfall	0
Deepest snow cover	0

Records on 18 August 1999 by timescale: all-time 0, monthly 19, daily 869.

How Much Records Were Beaten By

656 broken records

Margins by which the 656 broken records beat the old ones, in degrees Celsius for temperature and millimetres for precipitation and snow; the largest margin was 71.3. Ties are not counted.

Top 20 by Significance

18 August 1999

Top 20 records on 18 August 1999 by significance
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
18 August 1999	Sedgwick 5 S, US	monthly rain	87.1 mm (3.4 in)	45.2 mm (1.8 in)	37 years	65 of 100 (Major)
18 August 1999	Wongan Hills, AU	daily rain	30.7 mm (1.2 in)	17.5 mm (0.7 in)	68 years	63 of 100 (Major)
18 August 1999	Lake Hinds, AU	daily rain	33.4 mm (1.3 in)	18.4 mm (0.7 in)	68 years	61 of 100 (Major)
18 August 1999	Hoogwoud, NL	daily rain	30.9 mm (1.2 in)	30.9 mm (1.2 in)	48 years	59 of 100 (Notable)
18 August 1999	Goomalling, AU	daily rain	27.4 mm (1.1 in)	13.9 mm (0.5 in)	68 years	58 of 100 (Notable)
18 August 1999	Mindalla, AU	daily rain	28.2 mm (1.1 in)	17.0 mm (0.7 in)	44 years	56 of 100 (Notable)
18 August 1999	Rustefjelbma, NO	daily rain	35.2 mm (1.4 in)	27.9 mm (1.1 in)	40 years	56 of 100 (Notable)
18 August 1999	Fort Hill, AU	daily rain	26.0 mm (1.0 in)	11.3 mm (0.4 in)	68 years	52 of 100 (Notable)
18 August 1999	Postville, US	daily rain	50.8 mm (2.0 in)	24.6 mm (1.0 in)	86 years	52 of 100 (Notable)
18 August 1999	Myakka Rvr Sp, US	daily rain	101.6 mm (4.0 in)	55.9 mm (2.2 in)	36 years	49 of 100 (Notable)
18 August 1999	Colquitt 2 W, US	daily rain	82.0 mm (3.2 in)	71.3 mm (2.8 in)	16 years	49 of 100 (Notable)
18 August 1999	San Pedro, MX	daily rain	83.3 mm (3.3 in)	38.3 mm (1.5 in)	38 years	48 of 100 (Notable)
18 August 1999	Strawberry North, AU	daily rain	27.0 mm (1.1 in)	7.9 mm (0.31 in)	89 years	47 of 100 (Notable)
18 August 1999	Velikie Luki, RU	daily rain	26.6 mm (1.0 in)	13.6 mm (0.5 in)	65 years	47 of 100 (Notable)
18 August 1999	Buracica, BR	monthly rain	60.3 mm (2.4 in)	14.3 mm (0.6 in)	24 years	46 of 100 (Notable)
18 August 1999	Wijk_Aan_Zee_1, NL	daily rain	38.7 mm (1.5 in)	20.2 mm (0.8 in)	34 years	46 of 100 (Notable)
18 August 1999	Monticello, US	daily high min	26.7 C (80.1 F)	2.8 C (5.0 F)	84 years	46 of 100 (Notable)
18 August 1999	Poplarville Exp STN, US	daily high max	38.3 C (100.9 F)	1.6 C (2.9 F)	96 years	46 of 100 (Notable)
18 August 1999	Ygoola, AU	daily rain	25.0 mm (1.0 in)	15.9 mm (0.6 in)	28 years	45 of 100 (Notable)
18 August 1999	Zverinogolovskaja, RU	daily rain	27.9 mm (1.1 in)	20.3 mm (0.8 in)	18 years	45 of 100 (Notable)

Significance is a score from 0 to 100 combining margin, the age of the old record and the length of the station's record. How it is computed.

The Same Date in Other Years

1797 to 1999

Records set or tied on this calendar date in each year from 1797 to 1999. 1999 had 888 records.

Counts for years before the ledger starts come from the same station rules.

Records on 08-18 in each year
Year	Records
1797	2
1805	1
1816	1
1827	1
1829	1
1830	1
1833	1
1841	1
1844	1
1845	3
1846	1
1847	1
1849	1
1851	1
1852	1
1853	1
1854	2
1855	1
1856	1
1861	1
1864	2
1866	1
1868	2
1869	1
1870	2
1872	1
1873	1
1875	3
1876	1
1878	1
1879	2
1883	3
1885	3
1886	3
1887	3
1888	2
1889	1
1890	1
1891	2
1892	6
1893	4
1894	4
1895	1
1898	4
1899	6
1900	2
1901	10
1902	8
1903	6
1904	8
1905	10
1906	40
1907	7
1908	21
1909	24
1910	16
1911	11
1912	21
1913	43
1914	37
1915	60
1916	71
1917	70
1918	53
1919	34
1920	51
1921	39
1922	129
1923	90
1924	225
1925	300
1926	168
1927	269
1928	141
1929	181
1930	150
1931	241
1932	382
1933	431
1934	638
1935	424
1936	766
1937	308
1938	243
1939	381
1940	434
1941	467
1942	333
1943	738
1944	325
1945	400
1946	416
1947	958
1948	315
1949	393
1950	683
1951	355
1952	405
1953	323
1954	622
1955	795
1956	580
1957	380
1958	580
1959	537
1960	599
1961	415
1962	428
1963	760
1964	443
1965	525
1966	573
1967	623
1968	795
1969	530
1970	597
1971	381
1972	493
1973	734
1974	639
1975	844
1976	917
1977	1,112
1978	854
1979	1,309
1980	771
1981	1,386
1982	563
1983	1,420
1984	600
1985	765
1986	861
1987	1,609
1988	1,351
1989	952
1990	920
1991	533
1992	1,497
1993	706
1994	1,027
1995	1,882
1996	760
1997	1,191
1998	923
1999	888
2000	1,183
2001	1,036
2002	1,306
2003	860
2004	1,050
2005	865
2006	842
2007	1,116
2008	1,265
2009	839
2010	1,167
2011	1,239
2012	1,247
2013	752
2014	751
2015	880
2016	704
2017	565
2018	462
2019	615
2020	1,541
2021	1,118
2022	1,237
2023	1,094
2024	696
2025	455
2026	545

Download the Data

Data for records on 1999-08-18: CSV or JSON. Field meanings are on the data page.

Sources: 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)) Made with Natural Earth. Public domain map data. Borders are Natural Earth's de facto depiction. Data as of 2026-10-17 (17 October 2026). Records are computed by this site and are not official.

Data as of 2026-10-16. Last revised 16 October 2026 (2026-10-16).

Margin	Records
0 to 10	556
10 to 20	59
20 to 30	31
30 to 40	6
40 to 50	2
50 to 60	1
60 to 70	0
70 to 80	1