Most people agree - the weather in Michigan can be frustrating. In East Lansing, we have four seasons (spring, summer, fall, and winter), but each can be slightly unpredictable. In late July/early August, average temperatures are between 20-22 degrees Celsius. However, this could vary significantly year to year. In addition, even when we have hot days, the evenings/nights might cool down to 13 degrees Celsius.
Michigan is absolutely beautiful when it is sunny, and in July and August we usually get the most sunshine. We also have an average of about 11 days each month with rain, so it is a good idea to bring an umbrella.
You can check the weather online (city: East Lansing).