To find the current temperature, you need to subtract the temperature change from yesterday's temperature:
Initial temperature: 26 degrees Celsius
Temperature change: -15.5 degrees Celsius
Current temperature = Initial temperature + Temperature change
Current temperature = 26 + (-15.5)
Current temperature = 26 - 15.5
Current temperature = 10.5 degrees Celsius
So, the current temperature is 10.5 degrees C.