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Temperature Converter

Last verified: • Updated for 2026/26 tax year

Convert between Celsius, Fahrenheit, and Kelvin instantly. Perfect for UK weather, cooking, and science.

20.00°C
Celsius
68.00°F
Fahrenheit
293.15 K
Kelvin
Room temperature - comfortable indoor conditions

UK Oven Temperature Guide

Convert between Gas Mark, Celsius, and Fahrenheit for perfect cooking results.

180°C
Celsius
350°F
Fahrenheit
Gas 4
Gas Mark
Moderate oven - ideal for cakes and casseroles

Quick Gas Mark Reference

Gas ¼
110°C / 225°F
Gas 1
140°C / 275°F
Gas 2
150°C / 300°F
Gas 3
160°C / 325°F
Gas 4
180°C / 350°F
Gas 5
190°C / 375°F
Gas 6
200°C / 400°F
Gas 7
220°C / 425°F

Fan Oven Tip

If using a fan oven, reduce temperature by 20°C (or 25°F) or reduce cooking time by 10-15%.

UK Weather Context

The UK officially uses Celsius. Here's what temperatures feel like in British weather.

15°C
Celsius
59°F
Fahrenheit

Mild - Typical Spring/Autumn Day

Light jacket or cardigan recommended. Good weather for outdoor activities.

UK Temperature Guide

-10°C 0°C 10°C 20°C 30°C 40°C
FreezingBelow 0°C (32°F)
Cold0-10°C (32-50°F)
Mild10-15°C (50-59°F)
Warm15-25°C (59-77°F)
Hot25-30°C (77-86°F)
HeatwaveAbove 30°C (86°F)

Batch Temperature Conversion

Convert multiple temperatures at once. Enter values separated by commas.

Temperature Conversion Formulas

Understanding how temperature scales relate helps you convert quickly, even without a calculator.

°F = (°C × 9/5) + 32

Celsius to Fahrenheit: Multiply by 1.8, then add 32

°C = (°F - 32) × 5/9

Fahrenheit to Celsius: Subtract 32, then multiply by 0.556

K = °C + 273.15

Celsius to Kelvin: Simply add 273.15

Quick Mental Math

Celsius to Fahrenheit: Double the Celsius and add 30 (rough estimate)
Example: 20°C ≈ (20 × 2) + 30 = 70°F (actual: 68°F)

Common Temperature Conversions

Celsius Fahrenheit Kelvin Description
-40°C-40°F233.15 KExtreme cold (scales meet)
-18°C0°F255.15 KVery cold winter day
0°C32°F273.15 KWater freezes
10°C50°F283.15 KCool autumn day
20°C68°F293.15 KRoom temperature
25°C77°F298.15 KWarm summer day (UK)
30°C86°F303.15 KHot day in UK
37°C98.6°F310.15 KNormal body temperature
38°C100.4°F311.15 KFever threshold (NHS)
40.3°C104.5°F313.45 KUK record high (July 2022)
100°C212°F373.15 KWater boils

UK Temperature Guide

The UK has a temperate maritime climate with mild temperatures year-round. Here's what to expect:

Typical UK Temperatures by Season

Season Average High Average Low What to Expect
Winter (Dec-Feb)7°C (45°F)1°C (34°F)Cold, possible frost/snow
Spring (Mar-May)13°C (55°F)5°C (41°F)Variable, warming up
Summer (Jun-Aug)21°C (70°F)12°C (54°F)Warm, occasional hot spells
Autumn (Sep-Nov)14°C (57°F)7°C (45°F)Cooling, more rain

Met Office Heatwave Thresholds

  • London: 28°C (82°F) for 3+ consecutive days
  • South East: 27°C (81°F)
  • Midlands: 26°C (79°F)
  • North/Scotland/Wales: 25°C (77°F)

UK Temperature Records

Highest: 40.3°C (104.5°F) - Coningsby, Lincolnshire, 19 July 2022
Lowest: -27.2°C (-17.0°F) - Braemar, Scotland (multiple dates)

Frequently Asked Questions

How do I convert Celsius to Fahrenheit?
Multiply the Celsius temperature by 9/5 (or 1.8), then add 32. Formula: °F = (°C × 9/5) + 32. Example: 20°C = (20 × 1.8) + 32 = 68°F. For quick mental math, double the Celsius and add 30 for an approximate answer.
Does the UK use Celsius or Fahrenheit?
The UK officially uses Celsius for all temperature measurements since 1962, including weather forecasts, cooking, and medical contexts. However, older generations may still reference Fahrenheit, and some UK media shows both scales. All official UK measurements, including Met Office forecasts, use Celsius.
What is normal body temperature in Celsius?
Normal human body temperature is approximately 37°C (98.6°F), though it can vary between 36.1°C and 37.2°C throughout the day. The NHS considers a fever to be 38°C (100.4°F) or above in adults. For children, consult NHS guidance as thresholds may differ.
What temperature is considered hot in the UK?
In the UK, temperatures above 25°C (77°F) are generally considered hot. The Met Office declares a heatwave when temperatures exceed regional thresholds (25-28°C depending on location) for three consecutive days. Most Britons find 20-25°C ideal, with anything over 30°C uncomfortably hot.
What is Kelvin used for?
Kelvin is the SI (International System) unit for temperature, used primarily in science and engineering. It starts at absolute zero (-273.15°C), the coldest possible temperature. Scientists use Kelvin in physics, chemistry, astronomy, and thermodynamics because it provides an absolute scale. Note: Kelvin doesn't use a degree symbol - write "300 K" not "300°K".
What oven temperature should I use for baking?
Common UK baking temperatures: Cakes typically use 160-180°C (320-350°F, Gas Mark 3-4). Bread uses 200-220°C (400-425°F, Gas Mark 6-7). Cookies use 180-190°C (350-375°F, Gas Mark 4-5). If using a fan oven, reduce by 20°C. Always preheat your oven before baking.
At what temperature are Celsius and Fahrenheit the same?
Celsius and Fahrenheit are equal at -40 degrees. This is the only temperature where both scales show the same number: -40°C = -40°F. This occurs because of the mathematical relationship between the two scales and serves as a useful reference point for understanding extreme cold.

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Reviewed by Dr. David Thompson, PhD

Physics educator with 18+ years experience. Member of the Institute of Physics (MInstP). Specialises in thermodynamics and measurement standards.

Institute of Physics Member

Last updated: 28 December 2025