Weather is what’s happening in the atmosphere around us at any time – whether it’s hot, cold, rainy, or windy. It affects our daily lives more than we realize.
Main Elements of Weather
✔️ Temperature – How hot or cold it is
✔️ Precipitation – Rain, snow, hail falling from sky
✔️ Atmospheric Pressure – Weight of air pressing down
✔️ Wind – Moving air with speed and direction
✔️ Humidity – Amount of water vapor in air
How We Measure Weather
1. Temperature
- Measured using thermometers (digital ones are most accurate now)
- Two main scales: Celsius (°C) and Fahrenheit (°F)
- Important calculations:
- Daily range = Max temp – Min temp
- Mean temperature = (Max + Min)/2
Imp Fact: India’s weather department (IMD) has a motto – “From sun comes rain, from rain comes food”!
2. Rainfall Measurement
- Uses a rain gauge – simple funnel and measuring cylinder
- Measured in millimeters (mm) – if 5mm water collects = 5mm rainfall
3. Atmospheric Pressure
- Measured by barometer in millibars (mb)
- Normal pressure at sea level = 1013 mb
- Low pressure (<1000 mb) can mean storms coming!
- At high places like Khardung La (5600m), pressure drops to ~650 mb making breathing hard
4. Wind Measurement
- Wind vane shows direction (like those arrow things on buildings)
- Anemometer measures speed (those spinning cup devices)
- Important for pilots, sailors and farmers
5. Humidity
- Measured by hygrometer as %
- 0% = completely dry air (never happens naturally)
- 100% = air fully soaked with water vapor
- Normal ranges:
- Dry day = 20-40%
- Humid day = 60-80%
Weather Stations
Modern Automated Weather Stations (AWS) do all these measurements automatically using sensors. They’re super helpful for:
- Agriculture
- Aviation
- Disaster warnings
- Climate monitoring
Cool Example: IMD set up an AWS at 4800m height in Sikkim to monitor glacial lakes!
Why Weather Prediction Matters
Accurate forecasts help us prepare for:
Cyclones and storms
Heavy rains/floods
Heat waves
Cold waves
They help fishermen, farmers, pilots, and even help in disaster management.
8. Questions and Answers
- Match the instrument with the weather element it measures.:
- (1) Hygrometer – (d) Humidity: Hygrometer measures the amount of water vapour in the air as relative humidity.
- (2) Anemometer – © Wind direction and speed: Anemometer measures wind speed with rotating cups and direction with a wind vane.
- (3) Barometer – (b) Atmospheric pressure: Barometer measures the weight of air above in millibars to detect pressure changes.
- (4) Thermometer – (e) Temperature: Thermometer measures how hot or cold the air is using Celsius or Fahrenheit scales.
- (5) Rain gauge – (a) Precipitation: Rain gauge measures rainfall depth in millimetres by collecting water in a cylinder.
- Jyotsna is deciding what clothes to pack for her school trip to Mumbai in June. She looks at the weather forecast, which predicts 29°C and 84% humidity. What would be your advice to her?:
- I would advise Jyotsna to pack lightweight, breathable cotton clothes like t-shirts and shorts for Mumbai’s 29°C temperature, and include an umbrella or raincoat due to the high 84% humidity indicating likely rain, ensuring she stays cool and dry in the warm, humid weather.
- Imagine that a small group of students is setting up a rain gauge. Here are some options for the site: 1. The school vegetable garden, 2. The terrace of the school building, 3. Open ground with elevated platform, 4. Compound wall of school, 5. Verandah of the school laboratory. Discuss in your group and finalise the site. Write down the reasons for your decision.:
- The best site for setting up a rain gauge is the open ground with an elevated platform because it is free from obstructions like trees or buildings that could block rain, ensures accurate collection of rainfall, and the elevated platform prevents ground water interference, providing a stable, flat surface for reliable measurements.
- Below is a chart taken from IMD, Jammu and Kashmir. Looking at the data available, write a short script to report the weather conditions in different parts of Jammu and Kashmir on the date shown. (Hint: Cover the temperature range, maximum and minimum temperatures, humidity, precipitation, etc.) :
- On 1st February 2024, Jammu and Kashmir experienced cold winter weather. In Srinagar, the maximum temperature was 6.5°C, minimum 0.2°C, with 89% humidity and 13.4 mm rainfall, plus 2.4 cm snowfall. Qazigund recorded a high of 3.2°C, low of -0.4°C, 97% morning humidity, 36.2 mm rain, and 22 cm snow. Pahalgam was colder with 1.1°C maximum, -4.1°C minimum, 96% humidity, 19.4 mm rain, and 23 cm snow. Kupwara had 5.1°C high, -0.7°C low, 97% humidity, 21.9 mm rain, and 10 cm snow. Kukernag reported 2.6°C maximum, -1.4°C minimum, 96–97% humidity, 35.2 mm rain, and 30 cm snow. Gulmarg was the coldest at -2.6°C high, -7.6°C low, 76–100% humidity, 35.2 mm rain, and 35 cm snow. Muzafarabad had 8.5°C maximum, -5.6°C minimum, 93% humidity, and 25.8 mm rain. The region saw significant precipitation, high humidity, and below-normal temperatures, indicating a wet and snowy day.
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