Vitamin D

Chicago

Vitamin D from the sun in Chicago

8 months of sun

In Chicago you can synthesize vitamin D from March to October.

From November to February synthesis isn't possible — this is when a supplement can help.

Exact window
February 22 – October 25

Chicago: we'll tell you the days you can make vitamin D.

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Today's sun in Chicago

Today's sunrise, sunset, golden hour and day length.

Year-round profile in Chicago

Daily hours with enough sun to synthesize vitamin D across the year.

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0 h10 h+
Daily hours with enough sun to synthesize vitamin D across the year.

Seasonal windows

  • March: between 10:00 and 15:00, about 12 min for 1000 IU.
  • June: between 08:00 and 16:00, about 6 min for 1000 IU.
  • September: between 10:00 and 15:00, about 10 min for 1000 IU.
  • December: synthesis isn't possible.

Estimated for Fitzpatrick type III skin, arms and face exposed, clear sky.

When to supplement in Chicago

During the months without solar synthesis, vitamin D comes only from food or a supplement. It is usually taken as D3, often with magnesium — which the body needs to activate it — and vitamin K (as K2), which contributes to the maintenance of normal bones.

More about supplements

Sunrise and sunset by month in Chicago

How sunrise, sunset and day length change over the year.

MonthSunriseSunset
07:1616:43
06:4917:21
07:0618:55
06:1219:30
05:3120:03
05:1520:27
05:2820:24
05:5919:50
06:3318:57
07:0618:05
06:4316:28
07:1216:21

Approximate values for mid-month (the 15th).

Frequently asked questions about vitamin D in Chicago

Can I get vitamin D from the sun in winter in Chicago?
In Chicago you can synthesize vitamin D from March to October.
How many minutes of sun do I need in Chicago?
In summer, about 12 minutes with arms and face exposed is enough for 1000 IU (Fitzpatrick type III skin, clear sky).
What time does the sun rise and set in Chicago?
It shifts with the seasons: in June the sun rises around 05:15 and sets around 20:27; in December it rises around 07:12 and sets around 16:21.
What is the longest day of the year in Chicago?
Longest day: June, with about 15 h of daylight. Shortest day: December, with about 9 h.
When is golden hour in Chicago?
It's roughly the last hour before sunset: in June it starts around 19:45 and in December around 15:36.

More about the sun, light and health in the guide