is a weather phenomenon likely to occur with reasonable regularity around a specific approximate calendar date.Barry R.G.
& Chorley R.J.
(1987), Atmosphere, Weather & Climate
, 5th ed, Routledge, ISBN 0416071422
The concept should not be confused with more general seasonal weather patterns. For example the British tradition that rain on St. Swithun's Day
(15 July) will be followed by forty days and nights of rain would (if true) represent a singularity, but the fact that May Day
is usually warmer than New Year's Day
locales is not.
Although folk tales such as St Swithun's Day generally have little credibility, some of these events have a more solid basis. Early scientific investigation involved the creation of calendars of singularities based on temperature and rainfall anomalies. Later and more successful work by Hubert Lamb
of the Climatic Research Unit
was based on air circulation patterns. Lamb's work analysed daily frequency of airflow categories between 1898 and 1947.Lamb H.H
(1950) Types and spells of weather around the year in the British Isles: Annual trends, seasonal structure of the year, singularities. Quart. J. Royal Met. Soc.
76/330, pp393-438. Similar work was carried out by Flohn
and HessFlohn H.
& Hess P. (1949): Großwetter-Singularitäten im jährlichen Witterungsverlauf Mitteleuropas (Statistisch-synoptische Untersuchungen 2). Meteorol. Rdsch.
, 2,... Read More