Sometime not even the blue hour gets you a blue sky. Especially whet it only stopped raining a short while ago. But all the clouds still reflect the street light, which can mad the whole scene yellow. Sometimes it looks quite interesting.
Same here, at 5am in the morning in Ljubljana. It was quite cold and the streets were still vet. But the photo came out quite nicely. This is a HDR created in Oloneo Photoengine from 5 exposures and then blended with some of the original brackets in Photoshop.