Problems With Kitchen Circuit in Summer?

I live in a mobile home, and whenever the weather gets above 90 degrees, our florescent light in the kitchen will not completely light, the oven won't work, because the igniter doesn't get hot enough (we've replaced the igniter twice), and the microwave works, but sounds very weak. All year round, except in the summer, everything works fine, and we don't have issues in any room except the kitchen in the heat. Unfortunately the summers where I live have a lot of 90+ days. Any ideas what might be causing this?