Shades

I have been trying to lose weight for a few months now. I went up to 195 by the time I was done writing my thesis, and I wanted to go down. To do so, I've been running every Monday, Wednesday, and Friday for increasing distances and speeds. I started at 5 mph for 3 miles with 3 walk breaks, and am up to 5.7 mph for 5.25 miles with 2 short walking breaks. I also lift weights on Tuesday, Thursday, and either Saturday or Sunday. I have cut my soda intake to a third, so about a can or less a day. I have also changed my lunch diet from pizza to Subway-type food. Other than that, I didn't change anything.

In about three and a half months, I've dropped about 13 pounds. I have a few questions-

- Is that a small or high amount?
- In the last two weeks, things have leveled off. I only lost 0.05 pounds last week, and things don't seem to be going down this week. I was 185 for about 6 years steady, but I currently want to go down to less than that. I have a chart to show the daily and weekly weights if you want to see it. I'm not crazy, but I am an engineer, so of course I wanted accurate data.
- Is it possible that the colder weather we've been having here the last few weeks is what's slowing down my weight loss?
- I'm 6' tall on the dime. What's a good weight to be?