I discovered that I love running in Wiesbaden as long as it is the right time of day. The city can get much more crowded than we anticipated. To avoid the street-packing crowds of walkers, shoppers and tourists one must run in the morning before 6am on a weekday and before 9am on the weekends when the weather is nice and just about any time of day when there is daylight the rest of the year, which isn't much, unfortunately. For the long summer days, we sacrifice the daylight in the fall and winter months. Early fall through late spring, it is getting dark by 4:30pm and sun doesn't rise until after 6am.
Despite the short windows runners have for peak weather conditions in the city, it is a great city for running most times of year. The Kurhaus Park is lovely and provides a paved trail to run laps around a lake and picnickers in the park. When it's not too crowded, this is my favorite place in Wiesbaden to run.