In describing the experiences of an airman who was shot down and having to evade the Germans, you may find it useful to be able to examine a contemporary calendar, know the phases of the moon, and know dates for changes of the seasons. The following websites will help. Keep in mind that time in German-occupied Europe was German time, not the time used by the Allied air forces operating out of England. I believe there was at least a one hour difference.
Calendar Calculator for WWII:http://www.timeanddate.com/calendar/monthly.html
Moon Phases Calculator: http://www.timeanddate.com/calendar/moonphases.html
Seasons Calculator: http://www.timeanddate.com/calendar/seasons.html