Let me start with the code:

from datetime import datetime
from matplotlib.dates import AutoDateLocator as ADL, _UTC as UTC
dmin = datetime(2013, 1, 8, 14, 5, tzinfo=UTC())
dmax = datetime(2013, 5, 28, 14, 5, tzinfo=UTC())
# ADL().get_locator(dmin, dmax)

from matplotlib import pyplot

x = [dmin, dmax]
y = [1, 2]
pyplot.plot(x, y)
pyplot.show()

When you run it, you will see that date axis is too full. I'm not sure what is the best solution to this issue, but after removing interval = 1 in AutoDateLocator.get_locator after comment that says "# We went through the whole loop without breaking, default to 1", all my charts looked pretty well.
(matplotlib 1.2.1)