Weather
Weathering the Weather
Whether the weather be fine
Or whether the weather be not
Whether the weather be cold
Or whether the weather be hot
We’ll weather the weather
Whatever the weather
Whether we like it or not
What is weather?
 Weather is the state of the atmosphere
at a specific place and time.
 It is what is happening outside right now.
 A few miles or a few minutes can
change the weather.
 At any given time, the weather is fair in
some places, while it rains or snows in
others
What is the weather like today?
Why is weather important?
 The weather affects our lives every day.
 It can have an impact on what type of
clothing we wear and how we spend
our free time.
 Weather also affects agriculture,
transportation, and industry.
What factors affect weather?
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Temperature
Humidity
Cloud Formation
Air Pressure
Wind Direction & Speed
Temperature
 The sun warms the earth’s surface and
therefore all the air above the surface
 Temperature - measure of how hot or
cold the air is.
 Remember, temperature is the
average motion (kinetic energy) of
molecules, so…
– high movement of molecules =
high temperature (hot)
– low movement of molecules = low
temperature (cold)
Humidity
 Humidity – the amount of water vapor in
the air
Would you go
to the beach
on a hot,
humid day, or
a cool, crisp
day?
– Absolute humidity – measure of how
much water vapor the air is capable
of holding. The hotter the air is, the
more moisture it can hold
– Relative humidity – measure of how
much moisture there is actually in the
air – expressed as percentage of
absolute humidity
Cloud Formation
 With cold air, molecules move slower so
droplets of water can start to stick
together and form clouds condensation
 Clouds form when water vapor
condenses on dust particles in the air
Types of Clouds
 Cumulus
– White, tall and puffy
– Definite base, and
look like cotton balls
 Stratus
– flat shapes
– stack up in layers
– low level and cover
most of the sky
 Cirrus
– Thin curves with no
clear shape found high
in the sky
– wispy, feathery clouds
– made of ice crystals
 Cumulonimbus
– tall, puffy, and gray
– may bring thunder and
lightning.
There are many more types of clouds. Basic
categories are used to classify them. Their names
combined to form over 10 different cloud types.
Air Pressure
 Air pressure is the weight of the air
pushing down
 High pressure – cool air descends
toward the Earth’s surface.
– Usually means clear sunny days
 Low pressure – warm air rises upward
into the atmosphere
– Usually means high humidity, clouds,
rain
 Looking at a weather map, you’ll notice the
air masses constantly moving around.
 The boundaries of these areas are called
fronts
Wind
 Air moves from areas where air pressure
is relatively high to areas where air
pressure is relatively low. This movement
of air is what we call wind.
 Winds are measured by direction and
speed
 A wind chill is the cooling in
temperatures that the wind causes