In Mexico it is frequently heard, in the mass media (radio, TV and printed press), as well as in colloquial jargon, the use of weather and climate as if they were synonyms. They are, however, two different concepts and it is necessary to leave their meaning clear, especially if we are going to make use of atmospheric surveillance reports (forecasts) in order to make socioeconomic decisions (e.g. agriculture, livestock, fishery, etc.).
Clear examples of how these two terms are misused: 1) “The ship shall set sail as soon as the climate changes” and 2) “Weather conditions have prevented planting”; both statements are incorrect, the ship may take 10 years to set sail and the planting would never take place. 
It is however correct to say that Hermosillo, Querétaro and Campeche have the same atmospheric weather at a given time; for example, it could rain on the same day in the three cities. It is clear that these three cities have different climatic conditions; their climate is far from similar, as we can gather from the vegetation that each city has.
 The confusion of these two terms is in Spanish; therefore, some of the examples may not translate.
Therefore weather would be understood as something temporary (minutes, hours and even days), variable (the temperature is not the same at noon than at 6 am) and, to a certain extent, unrepeatable; climate, even though it is defined with the same elements (temperature, rainfall, atmospheric pressure, winds, cloudiness, etc.), is a more permanent and stable condition, actually, according to the World Meteorological Organization climate standard is defined as the weather conditions for a period of 30 years.
Weather and climate are in constant transformation, while the first changes within short periods of time, the second one does it at longer terms. Such changes are known as climatic variability, it is usually something natural; seasons (spring, summer, fall and winter) are examples of this variability, and they usually change every three months.
Most of the activities carried out by men are sensitive to fluctuations of climate – from farming to a simple picnic- sometimes it does not even matter if these are moderate or severe, short or long. Forecasting is an important factor for the decision making process.
There are two different types of atmospheric forecasts: for weather and for climate. On the one hand, weather forecast implies the use of short term scales, a couple of days (short term forecast) and recently there is a new forecast that extends to about a week (medium term forecast) and, on the other hand, climate forecast implies the use of long term scales, up to four months. In summary there are short, medium and long term forecasts. It is important to be aware of these types, as they imply the use of very different technology.
We should bear in mind that due to the chaotic nature of our atmosphere, the few existing observations and the imperfections in the our knowledge of the physic responsible for the different atmospheric processes, including atmospheric forecast, have a certain degree of uncertainty and a limited time horizon.
The socioeconomic sector dedicated to agriculture is vulnerable to weather and climate. Whenever there is a given atmospheric situation going on (draught, frost) the stability and productivity of this sector is automatically at risk.
Natural phenomena by themselves do not imply a loss or damage. The disaster happens due to a combination of other factors such as environmental deterioration, lack of education and of organization and the socioeconomic characteristics of the grower. Once the loss has happened the development process is interrupted, as most of the attention and resources are deviated to the attention of the disaster. Therefore, the vulnerability of the agricultural sector is linked to diverse socioeconomic factors, a weak or non existing infrastructure, and lack of planning from growers to face meteorological threats.
The following books and documents are excellent sources on topics related to weather, climate, and climatic impact (draught, flood) in the different socioeconomic sectors.
|Last Updated on Tuesday, 28 June 2011 19:35|