The demand for automobiles would shift outward. The demand for automobiles would shift inward. The fall in temperature is unlikely to affect air conditioning in Maine or home heating in Florida. As we move down along a straight-line demand curve, the average quantity is rising while the average price is falling. This reduces the price elasticity of demand.
Total revenue is price times quantity.
When the demand curve is elastic, the percentage decline in quantity demanded is greater than the percentage rise in price. If demand is inelastic, then a price increase will raise total revenue. Moreover, the reduction in quantity should lower the total costs of the firm.