Weather is considered to be the atmospheric conditions that are happening now or within a few days. On the other hand, Climate represents the long term atmospheric patterns within which weather occurs. As the popular saying goes, "Climate is what you expect, and weather is what you get!".
Why do I care? Weather and climate describe the short and long-term occurrence of inclement weather, respectively. These occurrences describe the typical weather conditions for an area on any given day of the year.
Weather describes conditions in the atmosphere that are happening right now. It is the short term occurrence, or daily measurement, of fair or inclement weather. For dealing with weather, daily decisions are necessary. When it is raining, bring an umbrella; when it is stormy outside, take cover inside. Daily temperature, precipitation, and severe weather are all a part of everyday weather. If the meteorologist on TV says that it will be sunny today, this is defined as weather.
Below are pictures describing weather conditions. Figure A is a picture of lightning during a lightning storm. Figure B is a satellite image of Hurricane Ivan as the eye approaches the Florida coast in September 2004.
|Figure A: Cloud-to-Ground Lightning||Figure B: Hurricane Ivan (2004)
|Image from NOAA||Image from NOAA
Climate describes the long-term weather patterns over a specified time frame for a specific area. Most books which describe regional or world climate use a long-term average of weather conditions to describe what typical conditions are likely to be present at a particular location and time of year. The average amount of rainfall is considered a part of climate. Climate statistics include both average conditions and frequencies of occurrence of severe weather, heavy rainfall, and other weather events which could impact health and property.
The latitude of a location has a large impact on the climate for that area. This is primarily due to the amount of solar heating received, which varies as a function of latitude. However, locations with the same latitude may have different climates depending on multiple factors such as whether the location is close to the coast or if the location has significant topographic features, such as a mountain.
Figure C shows annual average precipitation for the US from 1961-1990.
|Figure C: Annual Average Precipitation from 1961-1990.|
Figure D below shows the annual average temperature across the US from 1961-1990.
|Figure D: Annual Average Temperature from 1961-1990.|
Figures E and F show similar conditions as above with emphasis on the southeast US. They show precipitation (in mm) and temperature (in degrees Celsius) averages over a 30-year period.
|Figure E: 30-year Average Precipitation (mm)||Figure F: 30-year Average Temperature (C)|
You can think of differences between weather and climate as similar to differences between people's day to day moods and their personalities. A person is likely to have a consistent personality over time which is described by their long-term behavior regarding talkativeness, optimism or pessimism, and other factors. However, that person may show a lot of variation in their day to day moods, depending on outside influences, state of health, and even how much sleep they receive. Similarly, the climate of a region shows the long-term characteristic behavior of weather over that region. However, the weather on any day can be quite different depending on what weather systems are moving through the area and affecting the day's temperatures, rainfall, and wind conditions.
How does this relate to agriculture?
Weather and climate are considered by some to be the most limiting factors in crop production. Successful growers need to consider the climate AND weather conditions that are present in a certain growing area, as well as the growth requirements of the crops. For example, have you ever wondered why cranberries are only produced in Oregon, Massachusetts, New Jersey, Wisconsin and Maine? Or why cotton is only produced in the southern part of the United States? One reason is that crops have basic growth requirements for water, sunlight and temperature. For example, peanuts require 140 to 160 days of growth at temperatures above 56 degrees to reach complete maturity. These growing conditions exist in the Southern part of the US, but growing season is simply not long enough in the northern parts of the US for peanut production.
|Figure G: Downy Mildew in Cucumbers
||Figure H: Irrigation on Corn
|Image courtesy of Bridget Lassiter
||Image courtesy of Bridget Lassiter
Weather plays a slightly different role in crop production. Different weather patterns can affect crops in different ways. For example, some crops can withstand long periods of drought, and then recover when rain (or irrigation) finally arrives â€“ tobacco is one crop like this. Other crops can withstand very high temperatures, and still produce high yields (such as corn, cotton and peanut). Still other crops can technically produce well in various weather conditions, but still might be plagued with insect or disease problems in times when the weather is not ideal. One good example would be cucumber production in North Carolina that can be plagued with yield-limiting levels of downy mildew when rainfall or relative humidity remains high for extended periods of time.
For those reasons, weather AND climate play a role in where crops are grown, and how those crops must be managed.
Links to National Science Education Standards:
7th grade science: 7.E.1.4 : Predict weather conditions and patterns based on information from weather data collected through observations and measurements, weather maps, and cloud shapes and types.
Earth Science: EEn.2.6.1 : Differentiate between weather and climate.
Activities to accompany the information above:
Activity: Climate Variability (Link to original activity).
Teacher Set-up Instructions
Description: This activity focuses on how long-term climate average is related to climate variability and how climates can change through and increase or decrease in average temperature over a period of time.
Activity: The Weather (Link to original activity)
Description: This activity focuses on observing atmospheric conditions over a 4-day period. Students take observations for temperature, air pressure, wind speed and direction, and record sunrise and sunset. The measurements the student records are then compared with a NC State Climate Office station's measurements.