Dew point is the tempurature the air cannot hold the weight of the water in it. The water then begins to condense and form droplets. This tempurature is always below or equal to the air tempurature.
Propane prices. Maine (ME) propane users spent an average of $2.724 per gallon over the 2012-2013 heating season. This is slightly higher than the 2.436 average for the country as a whole, for the reasons explained above (distance from major supply source, colder climate, higher demand).
Still, this is a good indication as to the variations you can expect in current propane prices from propane companies. Current propane prices per gallon are higher than they were last year. According to the US EIA, the average national current propane price is $2.76 per gallon (23 December 2013).