Temperature Converter UK 2025 | Celsius Fahrenheit Kelvin Calculator

Temperature Conversion Formulas

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

Common Temperature Conversions

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

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)

Temperature Scales in Everyday UK Life

Temperature affects nearly every aspect of daily life in the United Kingdom, from deciding what to wear in the morning to setting the oven for Sunday roast. Despite the UK officially adopting Celsius in 1962 as part of its metrication programme, understanding temperature in practical British contexts requires knowing how different scales apply across healthcare, weather forecasting, cooking, and home heating.

NHS Fever Guidelines and Body Temperature

The National Health Service uses Celsius exclusively for all medical temperature measurements. Normal adult body temperature is approximately 37°C (98.6°F), though the NHS notes that healthy body temperature can range between 36.1°C and 37.2°C depending on the time of day, physical activity, and individual variation. A temperature of 38°C (100.4°F) or above is considered a fever in adults according to NHS guidelines.

For babies and young children, the NHS advises that a temperature of 38°C or above is a high temperature. Parents are advised to use a digital thermometer placed under the arm for children under 5 years old, and forehead strip thermometers are considered less reliable. The NHS 111 service recommends seeking urgent medical attention if a baby under 3 months has a temperature of 38°C or above, or if a child of 3 to 6 months has a temperature of 39°C or above.

During the winter months, the UK Health Security Agency recommends keeping living rooms at a minimum of 18°C (64.4°F) for the health of elderly and vulnerable residents, with bedrooms at a minimum of 18°C as well. Temperatures below 16°C in the home can increase the risk of respiratory problems, while temperatures below 12°C can put strain on the cardiovascular system.

Met Office Weather and UK Climate Context

The Met Office, the United Kingdom's national weather service, reports all temperatures in Celsius. Understanding what different temperature readings actually feel like in the British climate is essential for daily planning. In the UK, an average January day brings highs of just 6-7°C (43-45°F) across England, while a typical July day sees highs of 20-22°C (68-72°F) in the south-east and 17-19°C (63-66°F) in Scotland.

The Met Office issues heatwave alerts when daytime temperatures exceed regional thresholds for three consecutive days: 28°C for London, 27°C for the South East, 26°C for the Midlands, and 25°C for northern England, Wales, and Scotland. The UK's all-time temperature record stands at 40.3°C (104.5°F), recorded at RAF Coningsby in Lincolnshire on 19 July 2022. At the cold extreme, severe weather warnings are typically issued when temperatures fall below -5°C, and the UK record low is -27.2°C (-17.0°F), recorded at Braemar in Scotland.

Wind chill is another important factor in UK weather. The Met Office uses the "feels like" temperature, which combines air temperature with wind speed to give a more accurate picture of how cold it actually feels outdoors. On a windy winter day, a reading of 5°C can feel like -2°C or lower, making the wind chill calculation particularly valuable for walkers, cyclists, and outdoor workers.

Cooking Temperatures and Home Heating

British cooking relies heavily on temperature precision, particularly given the UK's unique Gas Mark system. While most modern ovens display temperatures in Celsius, many classic British cookbooks and family recipes still reference Gas Marks or Fahrenheit. Key cooking temperatures include: 160-180°C (Gas Mark 3-4) for Victoria sponge and most cakes, 180-200°C (Gas Mark 4-6) for roast chicken and casseroles, and 220-230°C (Gas Mark 7-8) for Yorkshire puddings and pizza. The Food Standards Agency recommends cooking poultry to an internal temperature of at least 75°C (167°F) to ensure food safety, and reheated food should reach a core temperature of 70°C for at least 2 minutes.

For home heating, the Energy Saving Trust recommends setting thermostats to between 18°C and 21°C for a comfortable and energy-efficient home. Each degree you raise your thermostat above 21°C adds approximately 10% to your heating bill. With UK energy costs remaining a significant household expense, understanding the relationship between thermostat settings and comfort is more important than ever. Most modern combi boilers in UK homes have separate controls for radiator water temperature (typically set between 60-75°C) and domestic hot water (usually 50-60°C), with 60°C being the minimum recommended to prevent Legionella bacteria growth in water systems.

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