What model are you using to fit this? What is p0, popt, or pcov?
I looked at the curve_fit tutorial, so it seems like your model is:
where is your data, , , and are your model parameters, p0 are your initial parameter values, popt are you optimal model fit values, and pcov is your covariance matrix.
I fit the data that Kevin and I gathered a while ago for the heating/cooling test we performed.