June - October
This is Great Lakes territory—hot and steamy in summer with a chance of great outdoor festivals; crisp, cool and colorful in the fall, with area vineyards and orchards in the middle of their annual harvest. Note: Detroit is home to some of the best urban leaf peeping, ever—some neighborhoods feel almost like forests, with a few houses (sometimes occupied, sometimes not) thrown in for good measure.
November - April
Detroit’s winters are long and tough and if you're not up for lots of snow and ice, you might want to stay away this time of the year. There’s still plenty of fun to be had, and the annual Auto Show ensures that the frozen streets of Downtown come to life for a week or two each January. The rest of the time is best spent indoors, or at least off the roads, which can be treacherous when weather hits.
It can be cold, it can be extremely hot during the spring. The only thing to predict is the unpredictable. Either way, you're still north of some parts of Canada here. This is the month that hosts the city’s most critically acclaimed music festival, Movement, a celebration of electronic music that attracts around 100,000 revelers from around the globe to the increasingly appealing Detroit riverfront. If you're coming in for the fest, you might want to book your hotel a few months in advance.