Weather and climate

Weather is the manifestation of the state of the atmosphere. Plant growth and horticultural operations are affected by weather; the infl uence of rain and sunshine are very familiar, but other factors such as frost, wind, and humidity have important effects. It is not surprising that growers usually have a keen interest in the weather and often seek to modify its effect on their plants. Whilst most people depend on public weather forecasting, some growers are prepared to pay for extra information and others believe in making their own forecasts, especially if their locality tends to have different weather from the rest of the forecast area. Weather forecasting is well covered in the literature and only its component parts are considered here.

Climate can be thought of as a description of the weather experienced by an area over a long period of time. More accurately, it is the long-term state of the atmosphere. Usually the descriptions apply to large areas dominated by atmosphere systems (global, countrywide or regional), but local climate reflects the infl uence of the topography (hills and valleys), altitude and large bodies of water (lakes and seas).