Vitamin D in London

London is the southernmost European pilot but remains farther north than every North American pilot city. 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 London's sunlight estimate in the calculator

What the monthly model shows

The chart uses latitude 51.5074°, longitude -0.1278°, and elevation 11 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 London
MonthModeled sunlightGap to RDA*
January0 IU/day400 IU/day
February16 IU/day384 IU/day
March134 IU/day266 IU/day
April555 IU/day0 IU/day
May1,199 IU/day0 IU/day
June1,867 IU/day0 IU/day
July2,009 IU/day0 IU/day
August1,449 IU/day0 IU/day
September640 IU/day0 IU/day
October110 IU/day290 IU/day
November5 IU/day395 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?

UK advice uses a 10 µg (400 IU) daily reference and recommends that adults consider a supplement in autumn and winter, with year-round advice for some risk groups.

Read the current NHS 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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