Passing url image from state

I want to change the temperature from Celsius to Fahrenheit (and vice-versa) but I haven't found the correct approach to tackle this, I wrote a function that does the Celsius to fahrenheit conversion but it throws me an error. So I need someone that is able to open my brain and explain this to me haha (make me understand is what I'm saying).

Here is my code: https://codepen.io/manAbl/pen/aGymRg?editors=0011

And I put in a comment the following function, that is the one that is not working:

convertingTemperature() {
const { Fahrenheit, Celcius } = this.state;

this.setState({
  Fahrenheit: true,
});

const _Celcius = this.state.weather.weather && this.state.weather.main.temp;

const _Fahrenheit = Math.round(_Celcius * 5 / 9 + 32);

if(Fahrenheit) {
  this.setState({ temp: _Fahrenheit })
};

}

What I want to do is hold on my state a boolean so if the fahrenheit is true, I can do the conversion and I call my function, but the reason I think is not working is because I'm pulling out the value from my weather state object, that comes from my api call. So I want to pull out that value, into a separate state so I can make the conversions with it.