Temperature is measure how hot or cold other is, such together the external air temperature, your body temperature, temperature of water because that cooking, boiling, washing, etc.

You are watching: How hot is 15 degrees celsius

So, is it cold or warm when the temperature estimate says it will certainly be 5 degrees or it will certainly be 30 degrees? What temperature go water freeze at? Or boil at? What temperature is comfortable for her living room?


Using the modern-day Celsius mechanism of temperature measurement, we can conveniently determine how hot or cold it is. That was likewise known as Centigrade. This is due to the fact that it is based upon the freezing and boiling points of water v 100 degrees in between those temperatures.

The key SI unit of temperature is the kelvin, which steps absolute temperatures. But, for our daily usage, we usage Celsius i beg your pardon is straight related come kelvins. That is set so that pure water freezes at zero degrees Celsius and also boils in ~ one hundred levels Celsius.

This is a really easy system to find out as these 2 marker points space so easy to remember:

Freezing in ~ 0 °C

Boiling in ~ 100 °C

And through 100 degrees between those points, we deserve to specify temperatures utilizing 1 or 2 digit optimistic numbers. As soon as the temperature is negative, i.e. Listed below 0 °C, then we know that it is therefore cold the water will certainly freeze. Water will always be ice listed below 0 °C, fluid from 1 to 99 °C, and vapor from 100 °C upwards.

Here is a table showing some guidelines regarding Celsius temperatures:

Temperature °CWhat might be at this temperatureHow that feelsOther point out of interest

-30 (that is 30 degrees below zero)

Ice, freezer

Very cold if you are outside in this temperature, unbearable come most




Very cold still however bearable if in too many of warmth clothes



Water freezes, ice melts


Typical coldest average temperature because that UK in winter




Water has actually its the smallest volume at this temperature*





20Room indoorsWarm
25Warm roomWarm to hot
Typical preferably temperature because that British summer
30Hot dayFeeling hotTypical temperature for hotter countries


Body temperature

Very hot

This is the average person body temperature

40Washing device setting for clothing for normal washVery hot
If friend are outside in this temperature you will feel hot, but more so if humidity is high.If your internal body temperature will this level you room in peril of death.
50Extremely hotNot numerous places acquire this high in temperature, and this warmth you would require to find shade, drink water and stay cool.
60Washing maker setting for hot wash
Too warm to live inMost bacteria die at this temperature
90Washing maker setting because that hottest washToo hot to live inHumans cannot make it through such high temperatures
100Water boils in the kettle

Water transforms to steam
1000Lava indigenous a volcano

1535Melting suggest of iron


15 000 000

Core that the Sun

*Note the water expands as the temperature increases over 4 degrees, and as it goes colder below 4 degrees. That is volume will certainly be in ~ its the smallest at 4 °C. This is essential to remember once freezing water in the icebox or freezer, as the water will undoubtedly rise in volume together it freezes, and also the chillier it gets, the enlarge the ice gets. For this reason remember no to put water into a party that will certainly be in the freezer for much more than a minute or so, together the water inside will expand and break the bottle.

If you need to work in hot conditions, here are guidelines for rest periods needed:

TemperatureRest duration (per hour of work)

30 come 32 ºC

10 minutes

32 come 35 ºC

15 minutes

more 보다 35 ºC

at least 30 minutes

Remember that as soon as you watch a weather estimate on TV, in a newspaper or on the radio, that anything indigenous 20 degrees upwards is walk to it is in warm, over 25 degrees is hot, over 30 degrees is very hot. Listed below 20 is cool, listed below 10 degrees is cold, and below zero degrees means that it will certainly be icy outside as the water will freeze and also it will certainly feel very cold outside.

Kelvin (for the more scientific amongst us)

The kelvin (symbol: K) is the SI unit the temperature, and also is one of the 7 SI basic units. The is identified by two facts: zero kelvin is absolute zero (when molecular motion stops), and one kelvin is the fraction 1/273.16 of the thermodynamic temperature of the triple suggest of water (0.01 °C). The Celsius temperature range is now characterized in regards to the kelvin.

The kelvin is named after the british physicist and engineer william Thomson, 1st Baron Kelvin. Hence we have an additional metric unit named after a british person. Most metric units room not foreign at all, unlike °F i beg your pardon is Foreign! The level Celsius (°C) is named after the sweden astronomer Anders Celsius (1701–1744) but as the is now defined in regards to the kelvin, it is more British 보다 Fahrenheit, called after a German scientist.

The indigenous kelvin as an SI unit is effectively written with a lowercase k (unless at the start of a sentence), and also is never preceded by the words degree or degrees, or the prize °, unequal Celsius. This is since Celsius is a scale of measurement, conversely, the kelvin is a unit that measurement.

See more: What You Think And Reason With ​Definitions And Synonyms, What Do You Think Makes A Reason For Believing

The freezing suggest of water, as we understand from what we review above, is 0 °C, and 0 °C = 273.15 K. For every rise by 1 °C the temperature additionally increases by 1 K. Therefore 0 K = -273.15 °C, 100 K = -173.15 °C, 273.15 K = 0 °C, and the boiling allude of water is 373.15 K (100 °C).