Vitamin D in Greater Sudbury

Greater Sudbury is farther north and higher than Toronto, making its winter and shoulder-season estimates useful for northern Ontario residents. 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 Greater Sudbury's sunlight estimate in the calculator

What the monthly model shows

The chart uses latitude 46.4917°, longitude -80.9930°, and elevation 347 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 Greater Sudbury
MonthModeled sunlightGap to RDA*
January7 IU/day393 IU/day
February64 IU/day336 IU/day
March300 IU/day100 IU/day
April909 IU/day0 IU/day
May1,688 IU/day0 IU/day
June2,462 IU/day0 IU/day
July2,660 IU/day0 IU/day
August2,067 IU/day0 IU/day
September1,073 IU/day0 IU/day
October270 IU/day130 IU/day
November28 IU/day372 IU/day
December4 IU/day396 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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