Extinction Point is a new novel by author Paul Jones: The central character (Emily) needs to ride her bike out of New York during a strange red rain:
A very brief synopsis of Extinction Point
Emily Baxter is a 30 something reporter living in Manhattan New York. Across the globe there are reports of a strange red rain seemingly falling from nowhere. At exactly midday the rain falls on New York from a clear blue sky. Eight hours later everything in New York (and across the globe) except for Emily is dead.
Within 24-hours Emily witnesses the dead within her apartment building transform into something totally alien. They turn into a strange eight-legged spider like creature that rushes about a lot and chews through walls in an effort to escape and join the millions of other transformed creatures that are running about New York.
Emily makes contact with a research outpost in a remote island off the northern most shore of Alaska. The scientists there tell her they believe the weirdness she is witnessing is affected by the cold and recommend she leaves New York and head to their location.