Weather is less of a problem than most people think. I have five reasons why I think overcast days are no problem! First, if schedules are flexible - we can try to get the shoot scheduled to the clearest part of the day. Second, professional gear is "weather sealed" - far from submersible, but a little rain won't hurt! Third, the results look quite good - the light is nice and even when the sky is overcast and the camera can bring the vibrant colors back to life. Fourth, the interior photos look great too - without harsh sun coming through the windows, the interior of the home can shine even more. Here are a couple of examples of recent grey sky photoshoots:
My fifth and final point, an overcast day is a great candidate for sky replacement service! The lighting provided by an overcast sky is nearly the same as sunset. Believe it or not, the example below was a mid-day photoshoot, with a sky replacement. On completely overcast days I offer a discount on sky replacement service: just $25 for the entire set of exterior photos, or $10 for just the main exterior photo.