GeographyCBSE Class 11 · Solar Radiation, Heat Balance and Temperature

Factors Controlling Temperature, Its World Distribution and Inversion (Class 11 Geography, Fundamentals of Physical Geography, Chapter 8)

Updated 17 October 2026 · Fact-checked

Temperature is controlled by latitude, altitude (normal lapse rate 6.5 C per 1,000 m), distance from the sea, air masses and ocean currents, and local aspects. Isotherms broadly follow latitudes, bending more in January; the annual range is over 60 C in north-eastern Eurasia and 3 C between 20 S and 15 N. Inversion reverses the lapse rate on clear, calm winter nights.

Understand Factors Controlling Temperature, World Distribution and Inversion of Temperature

Why this topic matters. Factors and inversion are regular 3-5 mark questions.

1. Heat and temperature. Heat is the molecular movement of particles; temperature measures in degrees how hot or cold a place or object is.

2. Five factors. (i) Latitude: insolation varies with it. (ii) Altitude: the atmosphere is heated from below, so places near sea level are warmer; the normal lapse rate is 6.5 C per 1,000 m. (iii) Distance from the sea: the sea heats and cools slowly, land quickly; coastal places get a moderating influence and land and sea breezes. (iv) Air masses and ocean currents: warm air masses raise temperature and cold ones lower it; coasts with warm currents are warmer than those with cold currents. (v) Local aspects.

3. Annual range. Difference between the mean temperatures of the warmest and coldest months. NCERT's example for New Delhi: mean monthly temperature is (mean daily maximum + mean daily minimum) divided by 2; January 14.2 C and May 32.75 C give a range of 18.55 C.

4. January and July. Isotherms join places of equal temperature and are broadly parallel to latitudes, with larger deviations in January and in the northern hemisphere, which has more land. In January isotherms bend north over oceans (the North Atlantic is warmed by the Gulf Stream and North Atlantic Drift) and south over continents, most in the Siberian plain; the mean January temperature along 60 E is -20 C at both 80 N and 50 N. In the southern hemisphere isotherms are more parallel to latitudes: 20 C, 10 C and 0 C run along 35 S, 45 S and 60 S. In July equatorial oceans exceed 27 C and Asia along 30 N exceeds 30 C.

5. Range. Highest annual range (over 60 C) in north-eastern Eurasia because of continentality; least (3 C) between 20 S and 15 N.

6. Inversion. When temperature rises with height instead of falling, it is an inversion. Ideal conditions: a long winter night, clear sky and still air; it is normal over polar areas throughout the year. Effects: stable lower atmosphere, smoke and dust collecting under the layer, dense morning fog; lasts a few hours until the sun warms the earth.

7. Air drainage. Cold, dense air flows downslope at night under gravity and collects in valley bottoms with warm air above; this protects plants on slopes from frost damage.

Factors Controlling Temperature, World Distribution and Inversion of Temperature: key facts

Five factors: Latitude
Altitude: 6.5 C per 1,000 m
Distance from sea
Air masses and ocean currents
Local aspects; Controls.
Annual range: $H i g h es t o v er 60 C inn or t h - e a s t er n E u r a s ia ∣ L e a s t 3 C b e tw ee n 20 S an d 15 N ∣ N e w D e l hi : 32.75 - 14.2 = 18.55 C$; Examples.
Isotherm pattern: Broadly parallel to latitudes
Bend north over oceans, south over continents in January
Southern hemisphere more regular; Distribution.
Inversion: Normal lapse rate reversed
Needs long clear calm winter night
Effects: fog, stability, trapped smoke
Air drainage protects slopes from frost; Key points.

How to answer Factors Controlling Temperature, World Distribution and Inversion of Temperature questions

Temperature questions combine factor, example and effect.

1List the five factors with one line each.
2Use 6.5 C per 1,000 m for altitude sums.
3Explain isotherm bending with oceans and land.
4Quote annual range extremes.
5Draw inversion profile with fog effect.

Factors Controlling Temperature, World Distribution and Inversion of Temperature in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Hill station cooler than plains

Suppose a hill town 1,500 m above a plain at the same latitude records a cooler temperature.

Estimate the difference using the lapse rate.

Try it first, then show the solutionSolution

6.5 C per 1,000 m.
1.5 x 6.5 = 9.75 C.

Answer: About 9.75 C cooler, due to altitude.

Memory hook: Higher is cooler.

Foggy winter morning

Suppose a valley on a clear, still winter night has cold air at the bottom and warm air above, and in the morning thick fog.

Which phenomenon is this?

Try it first, then show the solutionSolution

Temperature rises with height near the ground.
Cold air drains into valleys.

Answer: Inversion of temperature, with air drainage and fog.

Memory hook: Cold sinks, fog forms.

Tricks to remember Factors Controlling Temperature, World Distribution and Inversion of Temperature

Short memory aids. Say each one aloud once, then use it on a question the same day.

L-A-S-A-L
Latitude, Altitude, Sea distance, Air masses and currents, Local
Use it when: Factors.
6.5 per km
Normal lapse rate
Use it when: Altitude.
60 and 3
Max and min annual range (C)
Use it when: Range.

Factors Controlling Temperature, World Distribution and Inversion of Temperature: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Lapse rate · 1 mark · MCQBoard level

The normal lapse rate is:
(A) 1 C per 1,000 m
(B) 6.5 C per 1,000 m
(C) 10 C per 1,000 m
(D) 0.65 C per 1,000 m

Try it first, then show the solutionSolution

Normal lapse rate is 6.5 C per 1,000 m (1 mark).

Answer: (B)

Example 2: Temperature at altitude · 2 marks · Very short answerBoard level

A place at sea level has a temperature of 30 C. Find the temperature at 3,000 m using the normal lapse rate. (2 marks)

Try it first, then show the solutionSolution

Fall = 3 x 6.5 = 19.5 C (1 mark).
Temperature = 30 - 19.5 = 10.5 C (1 mark).

Answer: The fall is 3 x 6.5 = 19.5 C, so the temperature is 10.5 C.

Example 3: Land and sea · 3 marks · Short answerHarder board level

Explain how distance from the sea affects temperature. (3 marks)

Try it first, then show the solutionSolution

Sea heats and cools slowly; land quickly (1 mark).
Places near the sea get a moderating influence (1 mark).
Land and sea breezes add to this (1 mark).

Answer: Water heats and cools slowly, while land heats and cools quickly. Places near the sea therefore show smaller temperature variation and are moderated by the sea and by land and sea breezes, whereas places far inland have a larger range.

Example 4: Assertion and reason: inversion · 1 mark · Assertion-reasonHarder board level

Assertion (A): Inversion is most likely on a long, clear, still winter night.
Reason (R): The ground radiates heat away and becomes cooler than the air above.
(A) Both true, R explains A
(B) Both true, R does not explain A
(C) A true, R false
(D) A false, R true

Try it first, then show the solutionSolution

The day's heat radiates away and the ground is cooler than the air above (1 mark).

Answer: (A)

Example 5: HOTS: isotherms bend · 5 marks · Long answerHOTS / competency

Explain why January isotherms bend north over the North Atlantic and south over Eurasia. (5 marks)

Try it first, then show the solutionSolution

Northern hemisphere has more land (1 mark).
Gulf Stream and North Atlantic Drift warm the ocean (1 mark).
So isotherms bend north over the ocean (1 mark).
Land cools quickly in winter (1 mark).
So isotherms bend south over Eurasia, most in the Siberian plain (1 mark).

Answer: The northern hemisphere has much more land, so land and ocean currents strongly affect temperature. The North Atlantic is warmed by the Gulf Stream and the North Atlantic Drift, so isotherms bend north over it. Over the continent, land cools quickly in winter and temperature falls sharply, so isotherms bend south, most in the Siberian plain.

Where students lose marks in Factors Controlling Temperature, World Distribution and Inversion of Temperature

The slips examiners see most often, and what to write instead.

Mistake: Confusing lapse rate units
165 m and 6.5 C.
Wrong working
6.5 C per 165 m (mixing the two figures).
Right working
Use 6.5 C per 1,000 m (NCERT Ch. 8). Chapter 7 quotes about 1 C per 165 m, a slightly different average, so do not mix the two figures.
Do this: Remember both forms.
Usually costs: 1 mark.
Mistake: Saying sea heats quickly
Water seems light.
Wrong working
Sea heats faster than land.
Right working
Sea heats and cools slowly.
Do this: Land quick, sea slow.
Usually costs: 1 mark.
Mistake: Inversion in the day
Hot days.
Wrong working
Inversion happens on sunny afternoons.
Right working
On long, clear, calm winter nights.
Do this: Recall the conditions.
Usually costs: 1 mark.

Exam tips

Use 6.5 C per 1,000 m in altitude sums.
Mention the Gulf Stream when explaining January isotherms.
Link inversion with fog.

Practice questions on Factors Controlling Temperature, World Distribution and Inversion of Temperature

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
Air drainage is:
(A) movement of warm air uphill
(B) flow of cold dense air downslope at night
(C) horizontal wind
(D) sea breeze
Hint
Gravity.
Answer
(B)
Q2 · 2 marks · Very short answerBoard level
Compute New Delhi's annual range if the mean monthly temperatures are 14.2 C in January and 32.75 C in May. (2 marks)
Hint
Subtract.
Answer
32.75 - 14.2 = 18.55 C.
Q3 · 3 marks · Short answerHarder board level
Why is the annual range greatest in north-eastern Eurasia? (3 marks)
Hint
Continentality.
Answer
North-eastern Eurasia is far from the sea, so it lacks the moderating effect of oceans; land heats and cools quickly, giving a range of over 60 C. The least range of 3 C lies between 20 S and 15 N.
Q4 · 3 marks · Short answerHarder board level
Describe the effects of surface inversion. (3 marks)
Hint
Stability, smoke, fog.
Answer
It promotes stability in the lower atmosphere, smoke and dust collect beneath the inversion layer and spread horizontally, and dense morning fogs form, especially in winter; it lasts until the sun warms the earth.
Q5 · 4 marks · Short answerHOTS / competency
Frost damages crops in valley bottoms more than on slopes on clear winter nights. Explain using air drainage. (4 marks)
Hint
Cold air sinks.
Answer
On clear still nights the ground cools, and the cold dense air flows downslope under gravity and piles up in valley bottoms with warmer air above. Plants on the slopes are protected from frost, while those in the valley pockets suffer.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.What is an isotherm?Show answer
A line joining places of equal temperature.
2.What is the ideal condition for inversion?Show answer
Long winter night, clear sky, still air.
3.Which hemisphere shows larger deviations of isotherms?Show answer
The northern hemisphere.
4.What is the January temperature along 60 E?Show answer
-20 C at both 80 N and 50 N.

Factors Controlling Temperature, World Distribution and Inversion of Temperature: frequently asked questions

What is continentality?

The effect of distance from the sea on temperature range.

What is the difference between heat and temperature?

Heat is molecular movement; temperature measures hotness in degrees.

Is inversion permanent anywhere?

Yes, over polar areas it is normal throughout the year.