"This is from all the data I've been logging over the past 8 months.
Range is calculated as 21.5 * Leaf m/kWh. Ofcourse the shape & correlation to temperature won't change if we use a different figure. Temperature comes from http://www.beautifulseattle.com.

Data behind this.

Em: http://www.mynissanleaf.com/viewtopic.php?f=31&t=6701