Vitamin D in Winnipeg

Winnipeg is the northernmost large city in the pilot Canadian set and has a particularly short modeled UVB season. Location affects possible vitamin D production from sunlight; it does not change the age-based dietary reference intake or determine whether a particular person needs a supplement.

See Winnipeg's sunlight estimate in the calculator

What the monthly model shows

The chart uses latitude 49.8951°, longitude -97.1384°, and elevation 239 m. It is model version 2026.09 with reference year 2026. It is not a weather forecast or measured local UV record.

Modeled daily IU from 30 minutes between 10:00 and 14:00 local solar time, skin type II, long sleeves and pants (15% exposed), 40% cloud cover, grass surface, and SPF 0. Customize every input.
Monthly modeled vitamin D production and gap to adult RDA in Winnipeg
MonthModeled sunlightGap to RDA*
January2 IU/day398 IU/day
February27 IU/day373 IU/day
March181 IU/day219 IU/day
April665 IU/day0 IU/day
May1,360 IU/day0 IU/day
June2,066 IU/day0 IU/day
July2,222 IU/day0 IU/day
August1,640 IU/day0 IU/day
September764 IU/day0 IU/day
October150 IU/day250 IU/day
November9 IU/day391 IU/day
December0 IU/day400 IU/day

*Mathematical gap after modeled sunlight and an assumed 200 IU/day from food. This is not a supplement recommendation.

How much vitamin D do adults need?

Health Canada recommends 600 IU (15 µg) daily from all sources for ages 1–70 and 800 IU (20 µg) after age 70. Its food guide advises adults 51 and older to take a daily 400 IU supplement.

Read the current Health Canada guidance

Vitamin D and seasonal depression

Seasonal affective disorder is a form of depression related to seasonal changes in daylight. Low vitamin D can coexist with it, but research on vitamin D as a SAD treatment is mixed. Established options include clinician-guided light therapy, psychotherapy, and medication. Read the evidence guide to vitamin D and SAD.

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