Hi. I am by no means an expert but I ALWAYS use Coleus in my containers. I am here in Coastal Maine and it has been terribly wet and cold here as well. That is an issue for them as they seem to thrive for me in the heat of June/July. I also have mine in part sun as they don't seem to like direct sun but they do love the heat. Mine were very small when I bought them and we have finally had a good stretch of 70 degree weather. They are perking right up. I fertilized them about two weeks ago also. They will come around. I think everything needs some heat/sun right now. It's been a nasty Spring so far. Good luck. :)

Like Cosmolover said, they do love the heat. You'll see a really good difference when (if?) the heat comes. Our weather is junk here too, and my coleus have grown little.
A few of my coleus plants get 8 hrs of sun, from 8am to about 4pm. They're in hanging pots and I make sure they're watered on a daily basis, unless it rains. They do well there.
Hang in there and enjoy!

Kat

Same here. I put my cuttings outside in my coleus bed about 2 weeks ago, and they are doing absolutely nothing. They are leggy, somewhat discolored, and I'm about ready to pull them out and order from Rosy Dawn. But I'll wait another week or so (even though this week's weather is supposed to be wet & no sun).

Crossing fingers and toes for us coleus lovers...