Having joined the ranks of commuters clogging the roads and polluting the air, I feel a strange compulsion to document the amount of time I spend each day sitting, by myself, in a car.
Here's a plot showing the time I spend each day commuting. Light blue indicates morning; darker blue, evening.
The morning commute is both shorter and less variable than the same route in reverse direction in the evenings. Interestingly, although commutes on days with precipitation are slightly longer than on dry days, the difference is smaller than I would have expected—much smaller than I would have guessed based on the subjective experience of rainy, dark winter commutes.
The difference between morning and evening commutes is clearly visible in the two histograms below. On the left, the morning commute shows much greater consistency, with a fairly normal distribution around the mean. The evening commute shows double peaks, neither of them near the mean, and outliers towards both ends.