Phoenix landed in the Green Valley of Vastitas Borealis on May 25, 2008, in the late Martian northern hemisphere spring (Ls=76.73), where the Sun shone on its solar panels the whole Martian day.
https://github.com/davepinch/pinchy.cc/blob/master/content/camera-roll/2008/05/2008-05-24-examining-another-lake-phalen-drain.md