I'm building a greenhouse using recycled materials
The local Habitat for Humanity's "Re-Store" had some 80"x36" double pane glass in aluminum frames that were sliding glass door panels, and I had some leftover from a remodeling job a few years ago. I have a tall south-facing concrete block wall, so it can be a lean to. [I'll probably need more roof angle but I'll modify the drawing....first attempt at using Google SketchUp....at another time.]

 Good deal!!!  It will come in handy in your area!  Fred

looks great!

From a person with a greenhouse for a 4 years now, I will strongly suggest as much ventilation as you can afford, both at the top and bottom of the greenhouse.  Of all the fruits and veggies I have grown in the greenhouse, the figs need the most fresh air and breeze.  In fact, the best taste was attained by getting a good head start on the season in the greenhouse (about 3 weeks in my area, 6a) and bringing the pots out into the open air.  Then late in the season, the best ones are selected for reentry into the greenhouse around sept to finish ripening and extending the season another 2-3 weeks past normal.
Good luck, its a tonne of fun

Thanks for the advice. The prevailing winds blow from left to right, parallel to the wall, so it would make sense to put in put in ventilation points on each end to take advantage of it (Habitat's re-store has lots of used windows that would work.)
  
Also, I have two squirrel cage fans (like the one below), one of which I I have considered using with a thermostat to keep the greenhouse from getting too hot in summer.  It is probably overkill, since it was part of a forced air furnace for a 1500 sq ft house. However it was free and works fine, so I will probably use it somehow.