-15.5 degrees Celsius = 4.1°F (exact). Rounded: 4.1°F. In Kelvin: 257.65 K. In Rankine: 463.77°R.
Below freezing (0°C = 32°F). Water is solid ice at this temperature.
Below freezing: -15.5°C = 4.1°F. Key landmarks: 0°C = 32°F (freezing), −10°C = 14°F (cold winter), −20°C = −4°F (severe cold), −40°C = −40°F (where scales meet).
All temperature units: 4.1°F · 257.65 K (Kelvin) · 463.77°R (Rankine). Kelvin starts at absolute zero (−273.15°C). Rankine is used in some US engineering applications.
Formula: °F = (°C × 9/5) + 32. For -15.5°C: (-15.5 × 1.8) + 32 = -27.9 + 32 = 4.1°F. Reverse: °C = (°F − 32) × 5/9 = (4.1 − 32) × 0.5556 = -15.5°C.
-15.5°C = 4.1°F (exact: 4.1°F). Formula: (-15.5 × 9/5) + 32 = 4.1°F.
Multiply by 1.8 then add 32: -15.5 × 1.8 = -27.9, + 32 = 4.1°F. Quick estimate: double the Celsius value and add 30 → -1°F (approximate).
Add 273.15: -15.5 + 273.15 = 257.65 K. Kelvin is used in science — 0 K is absolute zero (the coldest possible temperature).
Below freezing (0°C = 32°F). Water is solid ice at this temperature. In Fahrenheit: 4.1°F is below freezing.