It is shown that the boiling points of all halogenated methane derivatives can be calculated as the sum of the contributions of three effects (London‐, Keesom‐ and Debije effect), even in the cases of the rather large deviations reported previously. The three effects are studied here to a higher approximation than was done formerly. It turns out that in a few cases the values calculated with the old formula for the London effect need a slight correction (refraction effect), but generally the formula holds without that. The formula for the Keesom effect seems to be correct in all cases. It can be understood that the formula for the Debije contribution to the boiling point according to van Arkel and Snoek does not hold so well. As a consequence of this fact we can easily understand the rather high TD + TK′ values for the fluorinated ethane and ethene derivatives previously reported (fluorine effect). Applying the combination of the refraction effect and the fluorine effect it is possible to predict the trends of the boiling points of isomers of the same type. All cases known in the literature are checked and no deviations are found.