The degree Celsius, also known as centigrade (or simply °C) was a unit of temperature based on the metric system.
The Celsius temperature scale was designed so that the freezing point of water was 0 °C, and the boiling point was 100 °C at one Earth atm, which resulted in the zero point of the temperature unit Kelvin (or "absolute zero") being at −273.15 °C.
The body function panels in sickbay measured a patient's body temperature in both Celsius and Fahrenheit. (Star Trek: The Original Series)
The replicators aboard a Federation starship like the USS Enterprise-D were calibrated to the Celsius metric system. (TNG: "The Defector")
Comparative list of temperatures
- −291 °Celsius: The average surface temperature of the planet Theta VIII, with wind speeds of up to 320 meters per second. (TNG: "The Royale")
- −260 °Celsius: The temperature of the accretion disk in a binary star system. (DIS: "The Vulcan Hello")
- −200 °Celsius: The temperature at which invidium became inert. (TNG: "Hollow Pursuits")
- −52 °Celsius: The lower end of the range for the surface temperature on Argeth. (DIS: "Scavengers")
- −40 °Celsius: The temperature that biothermally insulated booties would protect B'Elanna Torres' baby's feet against. (VOY: "Human Error")
- −20 °Celsius: The ambient temperature in the Argala habitat zone, found on board the Nyrian biosphere vessel. (VOY: "Displaced")
- −10 °Celsius: The temperature in the USS Voyager's gymnasium when the environmental controls failed in 2371. (VOY: "Twisted")
- −5 °Centigrade: The amount Shuttlepod 1's thermostat was reduced by in 2151 to free up power to enhance the efficiency of the atmosphere recyclers. (ENT: "Shuttlepod One")
- 1 °Celsius: The temperature for condensed suspension of water vapor, otherwise known as fog. (TNG: "Sub Rosa")
- 2 °Centigrade: The increase in the USS Enterprise-D bridge's ambient temperature ordered by a de-evolving Deanna Troi in 2370. (TNG: "Genesis")
- 3 °Celsius: The temperature of a glass of water Dr. Beverly Crusher gave to Will Riker when he awakened in a simulation created by Barash. (TNG: "Future Imperfect")
- 5 °Celsius: The temperature of a glass of water that Riker requested from the replicator to give to Acamarian Sovereign Marouk. (TNG: "The Vengeance Factor")
- 10 °Celsius: The temperature of a glass of water Reginald Barclay drank to calm himself in 2369. (TNG: "Realm of Fear")

Date, time and temperature in 2024
- 15 °C: The interior temperature at the San Francisco A District District Processing Center in August 2024. (DS9: "Past Tense, Part I", "Past Tense, Part II")
- 16 °Celsius: The ambient temperature beneath the surface of a Garan mining colony in 2373. (VOY: "Macrocosm")
- 17 °Celsius: The temperature when the morphogenic matrix of a Changeling was most malleable. (DS9: "The Begotten")
- 21 °Celsius: The temperature Humans preferred in order to operate most efficiently, according to Data's observations. (TNG: "Starship Mine")
- 21 °Celsius: The cabin temperature in the shuttlecraft Justman just before Jo'Bril flew it into the star Vaytan. (TNG: "Suspicions")
- 22 °Celsius: The temperature Spock kept his crew quarters aboard the USS Enterprise set to. (DIS: "Brother")
- 22.2 °Celsius: The temperature detected by initial scans made by the USS Grissom of Sector 1 on the Genesis Planet, indicating also that it was a forested region. (Star Trek III: The Search for Spock)
- 30 °Celsius: The maximum temperature at which liquefied platinum could remain stable. (ENT: "The Xindi")
- 32 °Celsius: The average temperature of Deep Space 9 when the Federation took over the station, indicating the temperature preference of Cardassians. (DS9: "Emissary")
- 37.2 °Celsius: Jean-Luc Picard's body temperature in 2367. (TNG: "Remember Me")
- 39.1 °Celsius (roughly 102.4 °Fahrenheit): The constant temperature in the internal climate aboard a Borg cube. (Star Trek: First Contact)
- 39.4 °Celsius: The temperature detected by initial scans made by the USS Grissom of Sector 2 on the Genesis Planet, indicating also that it was a desert terrain with minimal vegetation. (Star Trek III: The Search for Spock)
- 45 °Celsius: The higher end of the range for the surface temperature on Argeth. (DIS: "Scavengers")
- 46 °Celsius: The ambient temperature on both the Zooabud and Tanatuva habitat zones, on board the Nyrian biosphere vessel. (VOY: "Displaced")
- 50 °Celsius with a 90% humidity: The conditions on summers in the Rinax marshlands, the hottest it got in the sector surrounding the Talaxian system. Conditions of these marshlands also included vicious lavaflies on Rinax. (VOY: "Macrocosm")
- 55 °Celsius: The average temperature on Lambda Paz, a moon of Pentarus III, classified as barely class M with a desert-like surface. (TNG: "Final Mission")
- 55 °Celsius: The temperature level reached at the ore processing section of Terok Nor, when dilithium ore was being processed. (DS9: "Civil Defense")
- 60 °Celsius: The temperature at which Benjamin Sisko preferred his coffee. (DS9: "Call to Arms")

Readout of Federation habitat
- 76 °Celsius: The ambient temperature of both the Federation and Bourget habitat zones, found on board the Nyrian biosphere vessel. (VOY: "Displaced")
- 80 °Celsius: The temperature at which ginger tea with honey, Aunt Adele's cure for the common cold was served at. (TNG: "Ensign Ro")
- 150 °Celsius: The exact constant temperature of a pool of thick swirling ooze the Legarans preferred to inhabit in. (TNG: "Sarek")
- 300 °C: The temperature a Bersallis III fire storm could produce, with winds of over two hundred kilometers per hour. (TNG: "Lessons")
- 300 °Celsius: The approximate temperature the magma pockets beneath Atrea IV's surface had risen by after ferro-plasmic infusion had taken place. (TNG: "Inheritance")
- 323 °Celsius: The core temperature of an advanced long-range torpedo. (Star Trek Into Darkness, display graphics)
- 398 °Celsius: The temperature at which residic oil ignited. (ENT: "Civilization")
- 1,300 °Celsius: The temperature the hull of the USS Yangtzee Kiang ultimately rose to after being scanned by an artificial satellite in 2369 prior to crash landing. (DS9: "Battle Lines")
- 8,000 °Centigrade: The melting point of the Kalandan homeworld's surface. (TOS: "That Which Survives")
- 12,000 °C: The temperature the Enterprise-D's hull temperature rose to within a star's corona. (TNG: "Descent, Part II")
Variations in temperature
Although not explicitly stated in terms of "degrees of what", the following temperature references were most likely in Celsius.
- −28 degree temperatures were not uncommon in the middle of summer in the Northern Wastes of Andoria. (ENT: "The Aenar")
- 10 – 12 degree drop in temperature on Penthara IV was predicted within the first ten days after the impact of a type C asteroid on the planet. (TNG: "A Matter of Time")
- 12 onkians: The Romulan equivalent to a temperature of drinking water on the cold side of the Celsius system. (TNG: "The Defector")
- 15 degree drop in temperature was requested by the Female Changeling for the rooms on the Dominion Headquarters on Cardassia Prime after she was inflicted with the morphogenic virus. She noted that she didn't "share the Cardassians' love of heat;" nor apparently did Weyoun. (DS9: "Treachery, Faith and the Great River")
- 20 degree increase of temperature occurred on the planet where Dukat and Sisko were stranded in 2374, when the wind died down, much to the liking of Dukat's Cardassian physiology. (DS9: "Waltz")
- 50 degree surface temperatures on the planet Dozaria were too hot for the Breen, considering their homeworld was a frozen wasteland. (DS9: "Indiscretion")
- 200 degree surface temperatures were reached on the lunar prison on Meldrar I in the shade. (DS9: "Necessary Evil")