Anything from -30 to +60 any day of the week. Crazy weather up here.
The problem is not high idle due to cold. This 1000 RPM idle happens intermittently, such as when you come to a stop and disengage the clutch. If you let the clutch out just enough to put a slight load on the engine, the idle drops down to where it is supposed to be. Also sometimes if you rev the engine up and get off the go pedal the idle will hang up at the 1000 RPM. As Nukeman stated, his is about 80% of the time which is pretty well the way mine was before it was fixed.
I had that same problem with mine. After a couple of visits to a "good" dealer and a couple of calls to DC by the mechanic it was determined that the connections in the block that goes onto the ECM was defective as they were not sized properly. The story I got is that there was a change in manufacturers of this part. The right connectors were ordered and installed and it has idled properly ever since. I could also lock the doors with the switch on the door with it open and the engine running and also had erratic engine fan operations. This fixed all the problems. The only PO of this is that even though DC acknowledged a defect it was my nickle as I was just out of warranty. They would not even consider any good will. My truck is not the only one that this dealer has had the same problem with. Also my truck was an early 03 built in 02.