Date: January 23rd, 2017 1:52 PM
Author: dashing elite jap associate
Below approximately 30°latitude (south of Los Angeles/Dallas/Atlanta/Cairo)
15-30 minutes of midday sun (15 for those with lighter skin; 30 for those with darker skin)
or 2,000 IU supplemental vitamin D
Between 30° latitude (sample cities above) & 40°latitude (Portland/Chicago/Boston/Rome/Beijing)
From February through November
15-30 minutes of midday sun (15 for those with lighter skin; 30 for those with darker skin)
or 2,000 IU supplemental vitamin D
From December through January
2,000 IU supplemental vitamin D
Between 40° latitude (sample cities above) & 50°latitude (Edmonton/London/Berlin/Moscow)
From March through October
15-30 minutes of midday sun (15 for those with lighter skin; 30 for those with darker skin)
or 2,000 IU supplemental vitamin D
(http://www.autoadmit.com/thread.php?thread_id=3501020&forum_id=2#32439399)