The amount of vitamin D that your skin is able to make is affected by several factors:

Time of day:
- The time of day can affect the amount of vitamin D your skin is able to make because the production of vitamin D is dependent on exposure to sunlight.
- The best time to get vitamin D from the sun is between 10 am and 3 pm when the sun is at its highest point in the sky.
- During this time, the sun's rays are more direct, increasing the production of vitamin D in the skin.

Season:
- The season can also affect the amount of vitamin D your skin is able to make.
- During the summer months, when the days are longer and the sun is higher in the sky, there is more opportunity for sun exposure and vitamin D production.
- In contrast, during the winter months when the days are shorter and the sun is lower in the sky, there is less opportunity for sun exposure and vitamin D production.

Geographical location:
- Where you live can impact the amount of vitamin D your skin is able to make.
- People who live closer to the equator receive more direct sunlight throughout the year, which increases their ability to produce vitamin D.
- In contrast, people who live further away from the equator may have less sun exposure and therefore may have a lower ability to produce vitamin D.

Skin color:
- Skin color can also affect the amount of vitamin D your skin is able to make.
- People with darker skin have more melanin, a pigment that provides some protection against the harmful effects of the sun's ultraviolet (UV) rays.
- Melanin can reduce the skin's ability to produce vitamin D from sunlight.
- As a result, people with darker skin may require more sun exposure to produce adequate levels of vitamin D compared to those with lighter skin.

Use of sunscreen:
- The use of sunscreen can also impact the amount of vitamin D your skin is able to make.
- Sunscreen blocks the sun's UV rays, which are necessary for the production of vitamin D.
- While it is important to protect your skin from sunburn and skin damage, excessive use of sunscreen or high SPF levels may limit the skin's ability to produce vitamin D.
- It is recommended to balance sun protection with adequate sun exposure to maintain optimal vitamin D levels.

In conclusion, the amount of vitamin D your skin is able to make is influenced by the time of day, season, geographical location, skin color, and use of sunscreen. It is important to consider these factors and ensure appropriate sun exposure to maintain adequate vitamin D levels.