Difference between Weather and Climate

Contributed by:
Steve
This booklet refers to the confusion that comes from weather and climate being intimately connected, and this confusion is often highlighted in discussions about our changing climate.
1. What is the Weather
climate ?
and
difference between
Weather and climate are not independent. Our communities and farms are affected by short-
The confusion comes from weather and climate being term weather events. Their long-term sustainability is
intimately connected to each other, and this confusion affected by climate and climate variability attributed to
is often highlighted in discussions about our changing natural processes and human activities. Figure 1 depicts
climate. Weather and climate are not independent. The how weather and climate are intertwined. Over time, the
averages of daily weather are used to monitor climate. weather forms the climate and influences the environ-
Changes in climate lead to changes in weather patterns ment (soil, hydrology, plants, and animals), and economic
including extremes. An easy way to remember the differ- viability of our human systems.
ence is that climate is what you expect, like a hot summer,
and weather is what you get, like a cool day in August.
The sun is the major Extreme weather
source of energy events, such as heat
for the planet. waves, droughts,
The atmosphere tornadoes, torrential
moderates the H2O
rains, and heavy
solar influence snowfall, are a
by moderating natural part of the
temperature. Earth’s climate.
Nonetheless,
CH4 extreme weather
and climate events
CO have significant
CO2
oxy
gen
2
effects on our
lives and on the
environment.
carbon
H2O
carbon
Greenhouse gases, Carbon dioxide is
such as water vapor, constantly being
carbon dioxide, CO2 exchanged among
methane, and the atmosphere,
nitrous oxide, absorb ocean, and land
H 2O
energy and trap it H2O as it is both
in the atmosphere. produced and
CH4
Activities such as N2O absorbed by many
urbanization, energy microorganisms,
consumption, land plants, and animals.
use change, and
agriculture influence
the environment.
Figure 1. Communities and farms are affected by short-term weather events. Their long-term
sustainability is affected by climate (long-term weather variation or expected weather) and
climate variability driven by natural and human processes.
2. Weather The concept of climate has broadened and evolved
in recent decades in response to the increased under-
Weather is the behavior of atmosphere at any given
moment. It is what we observe on a daily or weekly basis standing of the underlying processes that determine
and includes, but is not limited to, sunshine, rain, cloud climate and its variability. Earth’s climate starts with the
cover, wind, hail, snow, sleet, freezing rain, blizzards, ice sun, the sole energy source for our planet. Climate is
storms, and thunderstorms. influenced by interactions involving the sun, ocean, atmo-
sphere, clouds, ice, land, and living organisms (Figure 1).
We generally think about weather and how it Often, this is thought of as the “climate system.” Climate
affects our lives and activities. Weather can change varies by region as a result of local differences in these
from minute-to-minute, hour-to-hour, day-to-day, and interactions. The Great Plains has a continental climate.
season-to-season. This features wide variability from season to season and
year to year, with little moderating effect from large water
Climate bodies.
Climate is the long-term aggregation of weather that
occurs in an area and the extent to which those conditions Climate Normals
vary over long time intervals. When scientists talk about Meteorologists and climatologists regularly use
climate, they are looking at patterns of precipitation, “normal” for placing recent climate conditions into a
temperature, humidity, sunshine, wind speed, fog, frost, historical context. Climate “normals” are three-decade
and other variables, such as soil temperature and mois- averages of climatological variables, including tempera-
ture, that occur over a long period in a particular place. ture (Figures 2 and 3) and precipitation (Figures 4 and 5).
Normal Temperatures (1981-2010) for Ottawa, KS Normal rainfall (1981-2010) for ottawa, ks
100 6.00
90
5.00
80
70
4.00
Temperature (°F)
60
Rainfall (in.)
50 3.00
40
2.00
30
20 Maximum temperature
Minimum temperature 1.00
10 Mean temperature
0 0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Date Date
Figure 2. Ottawa, Kansas daily temperature normals for the 1981- Figure 4. Ottawa, Kansas rainfall normals by month for the 1981-
2010 period. 2010 period.
Normal Temperatures (1981-2010) for Minco, OK Normal rainfall (1981-2010) for minco, ok
100 6.00
90
5.00
80
70
4.00
Temperature (°F)
60
Rainfall (in.)
50 3.00
40
2.00
30
20 Maximum temperature
Minimum temperature 1.00
10 Mean temperature
0 0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Date Date
Figure 3. Minco, Oklahoma daily temperature normals for the 1981- Figure 5. Minco, Oklahoma rainfall normals by month for the 1981-
2010 period. 2010 period.
3. A “normal” of a particular variable (e.g., temperature)
is defined as the 30-year average. The current normal
Key Points
• Weather represents the atmospheric events
period in the United States is based on 1981 through
2010 data. over a short time period, such as in a
minute, an hour, or a day.
For example, the January minimum temperature
normal for Ottawa, Kansas (19.3 degrees Fahrenheit) • Climate represents aggregate weather
is computed by calculating the average minimum conditions over longer time periods, such as
daily temperature in January for each year from 1981 decades or centuries.
to 2010 and then averaging those values. NOAA’s
• Climate “normal” is the official three-decade
National Climatic Data Center (NCDC) released the 1981
through 2010 Normals on July 1, 2011. average of weather variables, such as air
temperature and precipitation.
Because climate normals provide a historical perspec-
tive and help us understand the unusualness of current
weather, they are commonly seen on local weather news
segments for comparisons with the day’s weather condi-
tions. Graphing the high, low, and mean temperature for a
single year over the normal for that location can help you
visualize how well conditions fit into the typical pattern
(Figures 6 and 7).
Normal Temperatures vs Daily values for Ottawa, KS
120
100
Glossary
80
Temperature (°F)
Climate – The “average weather” or more 60
specifically the statistical aspects of the atmo-
40
sphere-hydrosphere-land surface system that varies
over time ranging from months to millions of years. 20
The classical period for averaging climatic variables
as defined by the World Meteorological Organization 0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
is 30 years. Climate also describes long-term statis- Date
tical averages and measures of variability associated Normal maximum Daily high 2013
with daily weather. Normal minimum
Normal mean
Daily low 2013
Daily mean 2013
Climate change – Any systematic shift in the
long-term statistics of weather elements (such Figure 6. Ottawa, Kansas daily temperatures for 2013 compared to
as temperature, rainfall, or winds) sustained over 1981-2010 normals.
several decades or longer. This can include changes
to both averages of these elements as well as Normal Temperatures vs Daily values for minco, ok
120
measures of variability and extremes. These changes
can be caused by natural forcing (see definition for 100
forcing(s) below), such as changes in solar emission
or slow changes in the Earth’s orbital elements; by 80
Temperature (°F)
natural internal processes of the climate system,
60
such as glaciations; or by human activities (anthro-
pogenic forcing; for further information see 40
references).
20
Climate normal – The latest three-decade aver-
ages of climatological variables, including tempera- 0
ture and precipitation. Climate normals are updated Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Date
every 10 years, when data for the last full decade Normal maximum Daily high 2013
have been compiled. Normal minimum Daily low 2013
Normal mean Daily mean 2013
Figure 7. Minco, Oklahoma daily temperatures for 2013 compared
to 1981-2010 normals.
4. Climate variability – The pattern and range
References
Peter Tomlinson, DeAnn Presley, and Chuck Rice,
of climate parameters (aggregate weather) for a
Greenhouse Gases in Agriculture, MF3119, Kansas State
particular place or region over a given time period.
University, September 2013
These may include temperature, precipitation, and
frequency of extreme events.
Forcing – An agent that causes a change in a Resources
system, such as a climate system. A volcanic eruption Kansas
is an example of a natural forcing that can change ‒‒ Kansas Weather Data Library (climate.ksu.edu)
the composition of the atmosphere.
Precipitation – All forms of water particles that
Oklahoma
‒‒ Oklahoma Mesonet (mesonet.org)
fall from the atmosphere and reach the ground.
‒‒ Oklahoma Climatological Survey (climate.ok.gov)
These include rain, snow, sleet, and hail. It does not
include fog or dew, as those are not falling; nor does Regional
it include virga, water droplets or ice that form in ‒‒ High Plains Regional Climate Center
clouds but evaporate before reaching the ground. (hprcc.unl.edu)
Weather – The specific conditions of the atmo- ‒‒ Southern Climate Impacts Planning Program
sphere at a particular place and time, measured in (southernclimate.org)
terms of variables that include temperature, precipi- National
tation, cloudiness, humidity, air pressure, and wind. ‒‒ National Weather Service (weather.gov)
‒‒ NOAA Climate Science and Information (climate.gov)
‒‒ National Climate Data Center (ncdc.noaa.gov)
Authors
Peter Tomlinson, Assistant Professor, Kansas State University
Mary Knapp, Assistant State Climatologist, Kansas State University
Albert Sutherland, Assistant Extension Specialist, Oklahoma State University
Amber Campbell, Adjunct Assistant Professor and Project Manager, Kansas State University
This material is based upon work supported by:
U.S. Department of Agriculture, Project No. 2012-02355 through the National Institute for Food and Agriculture’s Agriculture and Food
Research Initiative, Regional Approaches for Adaptation to and Mitigation of Climate Variability and Change. Great Plains Grazing is
a group of research scientists, Extension specialists and consumer experts from Kansas State University, Oklahoma State University,
University of Oklahoma, Tarleton State University, Samuel Roberts Noble Foundation and the USDA’s Agricultural Research Service working
together to improve and promote regional beef production while mitigating its environmental footprint.
National Science Foundation, Grant No. 1043393. Any opinions, findings and conclusions or recommendations expressed in this material
are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF). Climate Change Mitigation in
the Central Great Plains (CCM) is one of four sub-projects in the Kansas NSF EPSCoR initiative. This sub-project addresses one of the grand
challenges of the 21st Century: evaluating and predicting the biological and ecological consequences of accelerating global climate change.
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Difference Between Weather and Climate?, Kansas State University, March 2015.
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