−9 degrees Celsius = 15.80°F (264.15 K). Use the copy buttons below for any format, or enter a custom value in the converter.
The Celsius scale sets 0°C at the freezing point of water and 100°C at its boiling point. The Fahrenheit scale, used primarily in the United States, sets those same points at 32°F and 212°F. To convert Celsius to Fahrenheit, multiply by 9/5 and add 32: °F = (°C × 9/5) + 32. For −9°C: (-9 × 1.8) + 32 = 15.80°F.
−9°C
15.80°F
264.15 K
Fahrenheit
15.80°F
Kelvin
264.15 K
Full (°C to °F)
-9°C = 15.80°F
Full (°C to K)
-9°C = 264.15 K
Enter any Celsius value to convert it live to Fahrenheit and Kelvin.
Here are three everyday situations where knowing that −9°C = 15.80°F makes a practical difference.
If a recipe involves simmering, fermenting, or proofing at -9°C, that's 15.80°F. For example, bread dough proofing at 25–30°C, chocolate tempering at 31–32°C, and sous-vide cooking at 55–65°C all require precise Celsius-to-Fahrenheit conversions when using US kitchen tools.
You're checking the weather for a trip abroad and the forecast shows -9°C. That's 15.80°F. Bring a heavy coat, thermal layers, and waterproof boots. Most weather apps let you switch between °C and °F, but knowing the conversion helps when reading local signage or talking to locals.
In a chemistry or physics class, temperatures are often given in Celsius and need to be converted for US-format worksheets, or converted to Kelvin for thermodynamics problems. -9°C = 15.80°F = 264.15 K. The Kelvin scale is used in the ideal gas law (PV = nRT) and other thermodynamic equations where absolute zero (0 K = −273.15°C) is the reference point.
See how −9°C compares to nearby temperatures in both Celsius and Fahrenheit.
Common questions about −9°C and its Fahrenheit equivalent, answered.