Plant species differ in that renewed growth in spring can be triggered by day length or by temperature or else by a combination of both. Day length is the same, year after year, for any given date. Ttherefore, any plant species that starts to grow again on widely different dates in different years resumes growth at least in part in response to temperature.
The argument that if on any particular day store management has decided that three detectives will be needed, it must be because business that day is expected to be heavy is most similar in its pattern of reasoning to the argument above.