Welsh Journals

Climatic Cycles and Fluctuations SUMMER 1960: WET, CLOUDY AND COOL by J. OLIVER OPTIMISTIC ANTICIPATION gave rise to hopes that 1960 would repeat the sunny summer of 1959. From the second half of April the weather seemed to give promise that this indeed might be so. The many hot sunny days of June appeared to be a foretaste of more to come. With the memory of the previous summer still fresh, most people readily accepted any suggestion that 1960 might follow the same pattern. Such suggestions were advanced on many different grounds. In north-west Europe past experience has given some support for recognising a tendency for alternating periods of hot summers and cold winters and of cool summers and mild winters every 12 to 13 years. The years with a greater range between winter and summer are described as continental those with a reduced contrast are termed maritime. The mild 1959/60 winter did not agree with a continental sequence of climate, but this was excused on the grounds that in all such periods of continental or maritime climate there are exceptions. Some proposals were based more simply on the idea that the climate once it is set in a particular vein tends to repeat itself over a period of years until a sudden change occurs and an altered pattern is introduced. The problem in this case is that the 1959 summer was an isolated instance and was hardly adequate evidence to substantiate the view that a run of hot summers and cold winters was beginning. Other long-period forecasts have been formulated after a careful investigation of the weather of the last 250 years. Instrumental readings before the middle of the nineteenth century are scattered, unreliable and limited in number. For the eighteenth century the information is increasingly sparse and a continuous sequence has to be pieced together from separate short records. The length of the available record of measured and comparable values hardly permits an accurate determination of whether or not climatic cycles exist. Many attempts have been made to identify cycles and periodic fluctuations of climate. Unfortunately, the cycles which have been identified from time to time have not behaved consistently. At best they have repeated themselves two or three times and then misbehaved. Shorter cycles of climate either are not well-defined or not entirely reliable. Longer cycles may exist but climatic records are too brief to enable their certain identification. A study of the climatic experiences of the past hundred years or more has not provided a much firmer foundation for long-range forecasting