Myself, I cannot understand why anyone would live in the far north. (anyplace where it ever snows) I have to have coconut trees all around!! Florida was too cold for me!
My weather is much the same as Jonna. The "long hot nights" make a huge difference in what will grow. Tomatoes expire, they are winter plants. Spinach doesn't even get the first true leaves before it keels over.
I started Adenium seeds in early May, and expect flowers by the end of September. I pay them a lot of attention, and feed a lot!