So, my oft-asked question arises again: how do we draw the line between a thriller and speculative fiction? The fact is, When the Wind Blows IS science fiction--it has simply been marketed as a thriller. Apparently, this was an effective strategy, because the book make a number of best seller lists.
When the Wind Blows is a mildly entertaining beach read. However, it does not meet the quality, thoughtfulness, or suspense that can be found in science fiction novels that explore the same or similar subjects. I encourage speculative fiction fans to read out of genre, but in this case, it probably isn't worth crossing over.