The study just seems to be stating the bleeding obvious; if more people cycle then more of them will be killed (at least initially as it could be expected eventually an increase in the number of cyclists will lead to a 'cultural change' and better awareness by drivers of cyclists etc etc). So by the same measure warm, dry weather will have a similar effect. That an increase in cycling fatalities may be the result of a fear of another way of dying maybe adds some piquancy or 'irony' but it's still hardly a revelation.
The study just seems to be stating the bleeding obvious; if more people cycle then more of them will be killed (at least initially as it could be expected eventually an increase in the number of cyclists will lead to a 'cultural change' and better awareness by drivers of cyclists etc etc). So by the same measure warm, dry weather will have a similar effect. That an increase in cycling fatalities may be the result of a fear of another way of dying maybe adds some piquancy or 'irony' but it's still hardly a revelation.