Table 2.

Season-adapted cut-offs for vitamin D insufficiency by calendar month

Calendar month	Median 25(OH)D [nmol/L]	Difference to median of August [nmol/L]	Season-adapted 25(OH)D cut-off [nmol/L]
January	40	15	35
February	40	15	35
March	40	15	35
April	40	15	35
May	41	14	36
June	50	5	45
July	53	2	48
August	55	0	50
September	53	2	48
October	52	3	47
November	45	10	40
December	43	12	38