Planetary Winds are the winds which blow almost in the same direction throughout the year.
So, they are called as Permanent or planetary winds.
E.g: Trade winds, westerlies and Polar easterlies.

i) The weight of air above a given area on the earth's surface is called atmospheric pressure or air pressure.
ii) The air pressure is measured by Barometer.
iii) The standard air pressure at sea level is 1013.25 mb.

1. Weather is the day today conditions of the atmosphere at any place as regards sunshine, temperature, cloud cover, Wind fog condition, air pressure, humidity, precipitation and such other elements.
2. It refers to short periods like a day, a week, a month or a little longer.
3. Weather changes from time to time in a day and one period to the other in a year.
4. The weather is cool in winter and hot in summer.

The horizontal movement of air is called wind.
The winds move from high pressure to low pressure.
Winds get their name from the direction from which they blow i.e, wind blows from south west is called southwest monsoon.
The wind systems are broadly categorized into three as follows.
i) Planetary winds
ii) Seasonal winds
iii) Local winds
Planetary winds:
These Winds are the ones which blow almost in the same direction throughout the year. So, they are called as Permanent or planetary winds.
Eg: Trade winds, Westerlies and polar easterlies.
Seasonal winds:
Seasonal winds are those which change their direction according to season in a year.
They are called as monsoon winds.
These winds blow from sea to land during summer and land to sea during winter.
Local winds:
These winds are the winds blow over a small area only during a particular time of a day or a short period of a year.
Eg: Land breeze and sea breeze.

1. The temperature of a unit volume of air at a given time is measured in scales like Celsius, Fahrenheit,
2. Meteorologist measures the temperature by the Thermometer, Stevenson screen and minimum and maximum Thermometer.
3. Atmosphere is mainly heated by outgoing radiation from 2 to 4 pm.
4. So the maximum temperature is recorded between 2 and 4 pm regularly and minimum temperature is recorded around 4 am before sunrise.