Station Changes in the Temperature Record

4,258 of 7,748 stations tested against their neighbours show a suspected change in annual mean temperature. The largest, and what a shift means.

Data as of 2026-10-12. Last revised 12 October 2026 (2026-10-12).

Key Facts

7,748 stations with at least 40 complete years and at least 3 suitable neighbours were tested; 4,258 have at least one suspected change (55 percent).
Each station's annual mean temperature is compared with up to 5 neighbours within 250 km using the standard normal homogeneity test.
A suspected change is a possible change at the station (a move, a new instrument or a new site); the record is kept as measured.
The largest listed shift is -4.4 C (-8.0 F) at Presa Danxho (Mexico) from 1978, with 5 neighbours.

How Suspected Changes Are Found

A weather station can change without the weather changing: it can be moved, get a new instrument or a new housing, or have its surroundings built up. Any of these can shift its readings up or down. The test looks for such a step by comparing a station with its neighbours, because neighbours share the regional weather and the step stands out in the difference.

Only stations with at least 40 complete years are tested. A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. For each station, up to 5 neighbouring stations are chosen: within 250 km, with at least 30 complete years in common and annual temperature anomalies that move together (a correlation of 0.6 or more). A station with fewer than 3 such neighbours is not tested.

For each year, the station's annual mean temperature is compared with the mean of its neighbours, and the standard normal homogeneity test (Alexandersson, 1986) looks for the year at which that difference most likely steps up or down. A step that passes the test's critical value for the length of the series is listed as a suspected change at that year. A second and third change are searched for only when the remaining segments each have at least 20 years, and at most 3 are listed for a station. How this build's file describes its method: Each station with at least 40 complete years was compared with up to 5 neighbouring stations within 250 km (at least 30 years in common and a correlation of annual mean temperature of at least 0.6; stations with fewer than 3 such neighbours were not tested). The standard normal homogeneity test (Alexandersson 1986) was applied to the difference between the station and its neighbours, with 95 percent (possible) and 99 percent (likely) critical values that depend on the length of the series, up to 3 changes per station, and none in the first or last 5 years. A change is a sign of a move, a new instrument or a new site, not of the weather, and the record is kept as measured.

What a Shift Means, and What It Does Not

The shift is the mean of the station's difference from its neighbours after the year, minus the mean before it, in degrees C. A positive shift means the station's annual mean temperature ran higher relative to its neighbours after that year than before it, and a negative shift lower. It is not a change in the station's own temperature: a station can warm and still show a negative shift if its neighbours warmed more.

A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. The strength depends on the size of the step and on how steady the difference series is, so a small step in a very steady series can be rated higher than a large step in a noisy one.

Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. The test does not know what happened at the station and this site does not claim a cause. A change that all the neighbours share, such as a regional warm spell, cancels out and is not flagged. Records are not adjusted: this site keeps every station record as measured and shows the suspected changes beside it.

Counts

As of 2026-10-12

Stations tested for a change against their neighbours and the suspected changes listed
Measure	Value
Stations tested	7,748
Stations with at least one suspected change	4,258 (55%)
Largest changes listed below	200
Listed as likely	171
Listed as possible	29
Listed with a positive shift	117
Listed with a negative shift	83

The Largest Suspected Changes

200 by size of shift

The table lists the changes with the largest shifts, in either direction. Each is a suspected change, not a confirmed one. Possible change at the station (a move, a new instrument or a new site); the record is kept as measured.

Largest suspected changes in station annual mean temperature, relative to neighbouring stations
Station	Country	Year	Shift (C)	Shift (F)	Strength	Neighbours
Presa Danxho	Mexico	1978	-4.4	-8.0	likely	5
Severo-Enisejsk	Russia	1966	-4.4	-7.9	likely	3
Severo-Enisejsk	Russia	1978	+4.1	+7.3	possible	3
Presa Jaripo	Mexico	1975	+3.7	+6.6	likely	5
Hermit 8 SE	United States	2004	-2.3	-4.1	likely	5
Hermit 8 SE	United States	2009	+2.3	+4.1	likely	5
Cheesman	United States	2004	+2.3	+4.1	likely	5
Mt Charleston Fire STN	United States	1991	-2.1	-3.9	likely	5
Cerralvo (Dge)	Mexico	1962	-2.1	-3.8	likely	4
Galeana	Mexico	1984	-2.0	-3.7	likely	5
Progreso	Mexico	2000	-2.0	-3.6	likely	5
El Sabino	Mexico	2001	+1.9	+3.4	likely	5
Yan An	China	2020	-1.9	-3.4	likely	4
Jalacingo	Mexico	1981	+1.9	+3.3	likely	5
Milan	Italy	2002	+1.8	+3.2	likely	5
Bondurant	United States	2019	+1.7	+3.1	likely	5
Circle Hot Springs	United States	2003	-1.7	-3.0	likely	5
Zacualtipan (Smn)	Mexico	1977	+1.7	+3.0	likely	5
Matias Romero (Smn)	Mexico	1975	+1.6	+3.0	likely	5
Miquihuana	Mexico	1994	-1.6	-2.9	likely	4
Villa Victoria (Dge)	Mexico	1965	-1.6	-2.9	likely	5
Sandberg	United States	2013	+1.6	+2.8	likely	5
Hillsdown	Canada	1935	-1.5	-2.8	likely	5
Clayoquot	Canada	1929	+1.5	+2.7	likely	5
Palma de Mallorca Cmt	Spain	1979	+1.5	+2.7	likely	5
Tenosique (Smn)	Mexico	1988	+1.5	+2.7	likely	5
Yushu	China	2020	-1.5	-2.7	likely	4
Hilok	Russia	1952	-1.5	-2.7	likely	5
Elko Rgnl AP	United States	1986	-1.5	-2.7	possible	5
Cheesman	United States	1994	-1.5	-2.7	likely	5
Union Hidalgo	Mexico	1983	+1.5	+2.6	likely	5
Culman	Russia	1966	+1.5	+2.6	likely	4
Tappen	Canada	1921	-1.4	-2.6	possible	5
Morro Bay Fire Dept	United States	2006	+1.4	+2.6	likely	5
Datong	China	2020	-1.4	-2.6	likely	5
Batesville Lvstk	United States	2005	-1.4	-2.6	likely	5
Shoshone 1 WNW	United States	2018	+1.4	+2.5	likely	5
Barrage A Lac Kempt	Canada	1939	+1.4	+2.5	likely	5
San Luis de la Paz	Mexico	1967	+1.4	+2.5	likely	5
Mt Charleston Fire STN	United States	1997	+1.4	+2.5	likely	5
Las Animas	United States	1931	+1.4	+2.5	likely	5
Cuautla (Smn)	Mexico	1955	-1.4	-2.4	likely	5
Tapachula (Dge)	Mexico	1988	+1.4	+2.4	possible	4
Pitiquito	Mexico	1976	+1.3	+2.4	likely	5
Ocean Falls	Canada	1930	-1.3	-2.4	possible	5
Plymouth 2 WSW	United States	1977	-1.3	-2.3	likely	5
Ahuatepec	Mexico	1965	+1.3	+2.3	possible	5
McBride 4SE	Canada	1936	+1.3	+2.3	likely	4
Port Arthur	Canada	1936	-1.3	-2.3	likely	5
Atlanga San Jose	Mexico	1978	+1.3	+2.3	likely	5
Abilene	United States	1988	+1.3	+2.3	likely	5
Rush 1N	United States	2000	+1.3	+2.3	possible	5
Provincetown 3 NW	United States	1932	+1.3	+2.3	possible	5
Washington 2 ESE	United States	1961	-1.2	-2.2	likely	5
Crane	United States	1974	+1.3	+2.3	likely	5
Shelby 2 NW	United States	1959	-1.2	-2.2	possible	5
El Boqueron	Mexico	1974	+1.2	+2.2	likely	5
Collegeville	Canada	1951	-1.2	-2.2	likely	5
Palmer Job Corps	United States	2005	+1.2	+2.2	likely	5
Ruxton Park	United States	2020	-1.2	-2.2	likely	5
Presa Guaracha	Mexico	1966	+1.2	+2.2	likely	5
Hermit 8 SE	United States	1994	+1.2	+2.2	likely	5
Grand Lake Stream	United States	2007	+1.2	+2.2	possible	5
Irwin 2 SE	United States	1927	+1.2	+2.2	likely	5
Riito	Mexico	1995	+1.2	+2.2	likely	5
Presa Danxho	Mexico	1972	+1.2	+2.1	likely	5
San Isidro	Mexico	1981	+1.2	+2.1	likely	5
Salamanca Obs.	Spain	2001	+1.2	+2.1	likely	5
Clayoquot	Canada	1918	-1.2	-2.1	likely	5
Tatlayoko Lake	Canada	1956	-1.2	-2.1	possible	5
South Pass City	United States	1978	-1.2	-2.1	likely	5
Moose Lake 1 SSE	United States	1991	+1.2	+2.1	likely	5
Dzaore	Russia	1993	-1.2	-2.1	likely	5
Wildrose 3NW	United States	1969	+1.2	+2.1	likely	5
Bakersfield AP	United States	1983	-1.2	-2.1	likely	5
Beulah 1 W	United States	1987	+1.2	+2.1	possible	5
Sybille Rsch Unit	United States	1999	-1.2	-2.1	likely	5
Old Forge	United States	1969	-1.2	-2.1	likely	5
Drummond Aviation	United States	1965	+1.2	+2.1	likely	5
Tapachula (Dge)	Mexico	1996	+1.2	+2.1	likely	4
El Tigre	Mexico	1997	+1.2	+2.1	likely	5
Fuerteventura/Aeropuerto	Spain	2003	+1.1	+2.1	possible	3
Puntilla	United States	2017	+1.1	+2.1	likely	5
Eufaula	United States	1927	+1.1	+2.0	likely	5
Jalostotitlan	Mexico	1960	-1.1	-2.0	likely	5
Rogers Pass 9 NNE	United States	1970	-1.1	-2.0	possible	5
Xining	China	1995	-1.1	-2.0	likely	3
Burney	United States	2002	+1.1	+2.0	possible	5
Las Plumas	United States	1932	+1.1	+2.0	likely	5
Atequiza	Mexico	1960	-1.1	-2.0	likely	5
Barre Falls Dam	United States	2016	+1.1	+2.0	likely	5
Lovelock	United States	1939	+1.1	+2.0	likely	5
Towner 2 NE	United States	1979	-1.1	-2.0	possible	5
Presa El Giron	Mexico	1993	+1.1	+2.0	likely	5
Ruxton Park	United States	1998	+1.1	+2.0	likely	5
Colotlan (Dge)	Mexico	1969	-1.1	-2.0	likely	5
Bagdarin	Russia	1992	-1.1	-2.0	likely	5
Milford	United States	1996	+1.1	+2.0	likely	5
Chickamauga 2 SW	United States	2017	+1.1	+2.0	likely	5
Baddeck	Canada	1950	+1.1	+1.9	likely	5
XI Ujimqin Qi	China	1959	-1.1	-1.9	possible	5
Pickens	United States	1997	+1.1	+1.9	possible	5
Nenana Muni AP	United States	1946	-1.1	-1.9	likely	5
Tappen	Canada	1951	-1.1	-1.9	likely	5
Terra Alta #1	United States	1974	+1.1	+1.9	likely	5
Sevierville	United States	1982	+1.1	+1.9	likely	5
Sam Rayburn Dam	United States	2000	+1.1	+1.9	likely	5
Tenerife/Los Rodeos	Spain	2002	-1.1	-1.9	possible	5
Salina 3 W	United States	2004	+1.1	+1.9	likely	5
Big Spring	United States	1971	-1.0	-1.9	likely	5
Miquihuana	Mexico	1982	+1.1	+1.9	likely	4
Huntingdon Wtp	United States	1994	-1.0	-1.9	possible	5
Lindong	China	2003	+1.1	+1.9	likely	5
Weifang	China	2011	+1.1	+1.9	likely	5
Tajique 4 N	United States	1935	+1.0	+1.9	likely	5
Karamay	China	1961	+1.0	+1.9	possible	3
Guerrero (Smn)	Mexico	1981	+1.0	+1.9	likely	4
Mahackala	Russia	1992	-1.0	-1.9	likely	5
Xinyang	China	2020	+1.0	+1.9	likely	4
Shelby 2 NW	United States	1969	+1.0	+1.9	likely	5
Pocomoke City	United States	1971	+1.0	+1.9	possible	5
Padilla	Mexico	1989	+1.0	+1.9	possible	5
Reno AP	United States	1999	+1.0	+1.9	likely	5
Yinchuan	China	2004	+1.0	+1.9	likely	3
La Paz (Dge)	Mexico	1992	+1.0	+1.8	likely	5
Coonabarabran (Namoi Street)	Australia	1994	-1.0	-1.8	likely	5
Valentine Nwr	United States	2006	+1.0	+1.8	likely	5
Desert Nwr	United States	2013	-1.0	-1.8	likely	5
Slippery Rock 1 SSW	United States	2016	-1.0	-1.8	likely	5
Bella Coola	Canada	1957	+1.0	+1.8	likely	5
Yautepec	Mexico	1967	-1.0	-1.8	likely	5
Custer	United States	1968	+1.0	+1.8	likely	5
Jerecuaro	Mexico	1970	+1.0	+1.8	likely	5
Apaseo	Mexico	1972	-1.0	-1.8	likely	5
Rogers Pass 9 NNE	United States	1978	+1.0	+1.8	likely	5
Hilland 2 NW	United States	1939	-1.0	-1.8	likely	5
Cameron Falls	Canada	1950	+1.0	+1.8	likely	4
Nueva Casas Grandes	Mexico	1958	-1.0	-1.8	likely	5
Ciudad Real	Spain	1980	+1.0	+1.8	likely	5
Omaha Eppley Airfield	United States	1980	-1.0	-1.8	likely	5
Santa Rosa	Mexico	1984	-1.0	-1.8	possible	3
Oceanside Marina	United States	1985	-1.0	-1.8	likely	5
San Luis Potosi (Dge)	Mexico	1986	+1.0	+1.8	likely	5
Lovelock Derby Fld AP	United States	1989	-1.0	-1.8	likely	5
Copper Camp	United States	1990	-1.0	-1.8	possible	5
Presa Danxho	Mexico	1994	-1.0	-1.8	likely	5
Mammoth Cave	United States	2000	+1.0	+1.8	likely	5
Enshi	China	2020	+1.0	+1.8	likely	3
Samaria	Mexico	1959	+1.0	+1.8	likely	5
El Puerto	Mexico	1983	+1.0	+1.8	likely	5
Stuttgart-Stadt	Germany	1984	-1.0	-1.8	likely	5
Grafton 1 NE	United States	1942	-1.0	-1.8	likely	5
Hanty-Mansijsk	Russia	1964	-1.0	-1.8	likely	3
Agassiz Refuge	United States	1969	+1.0	+1.8	likely	5
Hardin	United States	1971	+1.0	+1.8	likely	5
Sion 2	Switzerland	1977	-1.0	-1.8	likely	5
Libby 32 SSE	United States	1981	-1.0	-1.8	likely	5
Livingston Radio Wliv	United States	1999	-1.0	-1.8	likely	5
Dobbins Colgate Foreba	United States	1931	-1.0	-1.7	likely	5
Galeana	Mexico	1965	+1.0	+1.7	likely	5
Ysleta	United States	1981	+1.0	+1.7	likely	5
Rush 1N	United States	1991	-1.0	-1.7	likely	5
Tustin Irvine Rch	United States	1996	+1.0	+1.7	likely	5
Cortez	United States	1998	+1.0	+1.7	likely	5
Otog Qi	China	2012	-1.0	-1.7	likely	4
Linxi	China	2020	-1.0	-1.7	likely	5
Provincetown 3 NW	United States	1919	-1.0	-1.7	likely	5
Columbus	United States	2010	+1.0	+1.7	likely	5
Hailar	China	2011	-1.0	-1.7	likely	4
Weston	United States	1950	-0.9	-1.7	likely	5
Valle de Guadalupe	Mexico	1952	-0.9	-1.7	likely	5
Presa la Codorniz	Mexico	1982	+1.0	+1.7	possible	5
Placerville	United States	1984	+1.0	+1.7	likely	5
Sybille Rsch Unit	United States	2009	+1.0	+1.7	likely	5
Fraser	United States	1955	-0.9	-1.7	likely	5
Phoenix AP	United States	1970	+0.9	+1.7	likely	5
Lerma	Mexico	1977	-0.9	-1.7	likely	5
Pulaski Wwtp	United States	1991	-0.9	-1.7	likely	4
Chaoyang	China	1994	+0.9	+1.7	likely	5
Vernon	United States	2001	+0.9	+1.7	possible	5
Huntingdon Wtp	United States	2001	+0.9	+1.7	likely	5
Panama City 5N	United States	2004	+0.9	+1.7	likely	5
Los Castillos	Mexico	1961	+0.9	+1.7	likely	5
Adjuntas	Mexico	1986	-0.9	-1.7	likely	4
Tarandacuao	Mexico	2003	+0.9	+1.7	likely	5
Tappen	Canada	1927	+0.9	+1.7	likely	5
Montreal River	Canada	1927	-0.9	-1.7	likely	5
Sion	Canada	1937	+0.9	+1.7	likely	5
South Pass City	United States	1949	+0.9	+1.7	likely	5
Sahuaripa	Mexico	1962	+0.9	+1.7	likely	5
Tapachula (Dge)	Mexico	1981	-0.9	-1.7	likely	4
Freeland	United States	1927	+0.9	+1.6	likely	5
Tatlayoko Lake	Canada	1963	+0.9	+1.6	possible	5
Willcox	United States	1972	+0.9	+1.6	likely	5
Tombstone	United States	2012	+0.9	+1.6	possible	5
E Stroudsburg	United States	1966	+0.9	+1.6	likely	5
Seligman	United States	1969	-0.9	-1.6	likely	5
Letalisce Jozeta Pucnika Ljubl	Slovenia	1979	+0.9	+1.6	likely	5
Roosevelt Radio	United States	1987	-0.9	-1.6	likely	5
Nenana Muni AP	United States	2000	+0.9	+1.6	likely	5

Download the Data

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 2026-10-12. Suspected changes are computed by this site and are not official.