[OC] My truck’s seasonally sinusoidal, but remarkably consistent fuel economy over the past ~6 years

I've religiously tracked my fuel economy for the past ~6 years using Fuelly. Inspired by RamblinEagle13's post today, I finally exported the data and plotted it using Libre Calc. As with RamblinEagle13, I live in the Northeast U.S. Fuel economy for my truck really seems to be highly temperature dependent. Snow/4WD isn't a factor because 1) I don't have 4WD, and 2) the fuel economy starts dropping well before any kind of snow fall. My driving is fairly consistent year-round. The one-off very high peaks in the summer would be a long road trip of sustained highway driving. I drive slow, typically around 60, which is why you see peaks of 30+ MPG. My fuel economy drops rapidly over 60 MPH.