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).
1 (Minimums vary by location and tank size, and can range from 100-1,500 gallons.) More often, the propane company charges a fee of anywhere from $25-$250 a year but averaging around $75-$130 annually, depending on local rates, the size of the tank and whether it's aboveground or underground.