British Weather Extremes: Minimum Temperatures

Severe winter cold spells in Britain are associated with

  1. the advection of very cold air masses from the east or north
  2. the subsequent establishment of a deep and extensive snow cover.

The advection of very cold air is most effective when Continental arctic air (from north-west Russia) reaches central and southern parts of England and Wales on an easterly wind, thus crossing a relatively narrow stretch of the North Sea. Widespread low daytime temperatures occur in such circumstances, especially over snow covered ground. An especially severe 'cold wave' occurred in January 1987 when, on the 12th, daytime maximum temperatures at low altitudes ranged from around 0°C in the Outer Hebrides to -8°C at several places in eastern England; Southend in Essex, where 38 cm. of snow was lying, did not exceed -9°C between 9 a.m. and 6 p.m.

Snow and ice surfaces reflect incoming radiation (the albedo effect) and thus suppress daytime maxima. However the most pronounced "feedback" of snow cover is on overnight temperatures, through radiative cooling, since snow is an extremely poor conductor of heat, especially when freshly fallen and dry. In January 1982 the record minimum temperature for England, -26.1°C was recorded when skies cleared immediately following a deep powdery snowfall.

Very cold continental airstreams affecting Scotland are subject to greater warming as they approach over longer stretches of sea. There is therefore little difference between the absolute winter minima recorded in the Scottish Grampians and the English Midlands, despite the longer hours of winter darkness further north. However temperatures below -20°C are recorded much more frequently in Scotland. This is attributable to the higher altitude of much of the country and the more frequent incursions of air masses from Greenland and the colder parts of the North Atlantic; both these factors contribute to a higher frequency and extent of snow cover in Scotland.

Details of the lowest recorded temperature for each British County have been published in Journal of Meteorology, 8(83), pp. 269-272. Braemar, in the Eastern Grampians, has not only twice recorded the national record of -27.2°C but also logged Britain's annual `low' in 43 of the 109 years between 1875 and 1983 (Journal of Meteorology, 9(85), pp. 3-5). Other "favoured" locations for low temperatures are highlighted by the table of daily 'lows', from October to May, published in Journal of Meteorology, 10(96), pp.45-51.

At maritime locations, where there is a small diurnal range of temperature, low temperatures are entirely related to rapid advection on strong easterly winds. The Scilly Isles, Britain's mildest winter outpost, did not escape the extreme cold wave of January 1987. Temperatures on the islands plunged to -7.3°C and Tresco gardens sustained disastrous losses of tender trees and shrubs.

Feeble mid-winter sunshine makes little impression on areas of intense stagnant cold which have developed over snow-covered ground under clear anticyclonic conditions. Consequently some of the coldest days have also occurred in such situations including the astonishing day maximum of -19°C at Braemar on 10th January 1982 (Journal of Meteorology, 7(66), pp. 34-37). Maxima of -8°C to -12°C were recorded at several places in the English Midlands during the cold spells of December 1981 and January 1982, especially where patches of freezing fog lingered.

In the absence of snow cover many of the most severe frosts during the summer half year are recorded over light sandy soils which are also a very poor conductor of heat. Outstanding examples include the record low May and June values recorded in the Breckland of Norfolk. Other locations experiencing low summer temperatures are within deeply sheltered upland valleys e.g. in the Grampians, the Southern Uplands and in Mid Wales, where sharp local cooling of polar air masses can occur. Long dry spells in spring and early summer contribute towards late frosts by reducing the heat retention properties of the soil. At all times of the year the lowest overnight temperatures can be expected in relatively dry air masses.

TORRO contact member: Jonathan D.C. Webb


BRITAIN'S LOWEST RECORDED TEMPERATURES FOR EACH MONTH OF THE YEAR, 1875 - 1990
(at altitudes below 500 metres)

 

                 °C       °F

JANUARY         -27.2   -17.0   Braemar (Grampian)             10 Jan 1982

                -26.8   -16.2   Grantown on Spey (Highland)     8 Jan 1982

                -26.7   -16     Kelso (Borders)                17 Jan 1881

                -26.6   -15.9   Bowhill (Borders)              11 Jan 1982

                -26.3   -15.3   Braemar (Grampian)             11 Jan 1982

                -26.2   -15.2   West Linton (Borders)          11 Jan 1982

                -26.1   -15.0   Newport (Shropshire)           10 Jan 1982



FEBRUARY        -27.2   -17     Braemar (Grampian)             11 Feb 1895

                -25.6   -14     Braemar (Grampian)             10 Feb 1895

                -25.0   -13     Aviemore (Highland)             8 Feb 1895

                -25.0   -13     Braemar (Grampian)             23 Feb 1955



MARCH           -22.8   - 9     Logie Coldstone (Grampian)     14 Mar 1058

                -22.2   - 8     Grantown on Spey (Highland)    12 Mar 1958

                -21.7   - 7     Corwen (Clwyd)                  3 Mar 1965

                -21.7   - 7     Kinbrace (Highland)             3 Mar 2001

                -21.1   - 6     Houghall (Durham)               4 Mar 1947

                -21.1   - 6     Peebles (Borders)               4 Mar 1947

                -21.1   - 6     Braemar (Grampian)              4 Mar 1947

                -21.1   - 6     Braemar (Grampian)              8 Mar 1947



APRIL           -15.0     5     Newton Rigg (Cumbria)           2 Apr 1917

                -14.4     6     Eskdalemuir (Dumfries and

                                Galloway)                       2 Apr 1917

                -13.3     8     Braemar (Grampian)             11 Apr 1917

                -12.8     9     Garforth (West Yorkshire)      24 Apr 1908

                -12.8     9     Perth (Tayside)                24 Apr 1908



MAY             - 9.4    15     Lynford (Norfolk)               4 May 1941

                - 9.4    15     Lynford (Norfolk)              11 May 1941

                - 9.4    15     Fort Augustus (Highland)       15 May 1941

                - 8.9    16     Braemar (Grampian)              1 May 1927



JUNE            - 5.6    22     Dalwhinnie (Highland)           9 June 1955

                - 5.6    22     Santon Downham (Norfolk)        1 June 1962

                - 5.6    22     Santon Downham (Norfolk)        3 June 1962



JULY            - 2.5    27.5   Lagganlia (Highland)           15 July 1977

                - 2.5    27.5   St. Harmon (Powys)              9 July 1986



AUGUST          - 4.5    23.9   Lagganlia (Highland)           21 Aug 1973

                - 4.4    24.1   Grantown on Spey               21 Aug 1973

                - 3.3    26     Inverdruie (Highland)          21 Aug 1973

                - 3.4    25.9   Kinbrace (Highland)            25 Aug 1986



SEPTEMBER       - 6.7    20     Dalwhinnie (Highland)          26 Sep 1942

                - 6.2    20.8   Lagganlia (Highland)           27 Sep 1975

                - 6.1    21     Glenlivet                      23 Sep 1948

                - 6.1    21     Dalwhinnie                     15 Sep 1979

                - 6.0    21.2   Braemar (Grampian)             28 Sep 1974

                - 5.6    22     Santon Downham (Norfolk)       30 Sep 1969



OCTOBER         -11.7    11     Dalwhinnie (Highland)          28 Oct 1948

                -11.4    11.4   Braemar (Grampian)             20 Oct 1880



NOVEMBER        -23.3   -10     Braemar (Grampian)             14 Nov 1919

                -22.8   - 9     Braemar                        15 Nov 1919

                -21.7   - 7     Perth (Tayside)                14 Nov 1919

                -21.1   - 6     West Linton (Borders)          14 Nov 1919

                -21.1   - 6     Balmoral (Grampian)            14 Nov 1919

                -20.9   - 5.6   Kinbrace (Highland)            30 Nov 1985

DECEMBER        -27.2   -17.0   Altnaharra (Highland)          30 Dec 1995

                -26.7   -16     Kelso (Borders)                 3 Dec 1879

                -25.1   -13.4   Shawbury (Shropshire)          13 Dec 1981

                -24.9   -12.8   Grantown-on-Spey (Highland)    30 Dec 1995

                -24.6   -12.3   Aviemore (Highland)            30 Dec 1995