Is my Sun sign the same as my zodiac sign?

Yes. When someone says their sign, they mean the sign the Sun was in on the day they were born. The rest of the chart adds the Moon, the planets and the houses, which is why two people with the same sign can be unalike.

Why do some sources give different dates for a Sun sign?

The Sun enters each sign at a particular moment, and that moment lands on a different calendar day depending on the year and the time zone. Dates such as "about July 23 to August 22" are averages. A chart computed from the birth time settles it.

Can the Sun be retrograde?

No. Retrograde motion is an effect of the Earth overtaking or being overtaken by another planet. The Sun's apparent motion is the Earth's own orbit, so it always moves forward through the zodiac.

Astrology basics · The ten planets

What the Sun means in a birth chart, and why it is your sign

The Sun is a star, the one the Earth goes around, and the zodiac is the path it appears to trace against the background stars over a year. The Sun sign is where it stood on that path at birth, which is why a birthday is enough to know it. In a chart it says what a person is for, and where they feel most themselves.

What it is: A star; the center of the solar system
Zodiac cycle: A year, a month in each sign
Retrograde habit: Never
Sign ruled: Leo
Natural house: The 5th
Its domain: What a person is for, and where they feel most themselves

A star, and a month in each sign

The Sun does not move; the Earth does, and from here the Sun seems to slide eastward through the twelve signs, about a degree a day, about a month in each. It never appears to go backward, because the apparent motion is the Earth's own orbit, which has no pauses. Every other body in a chart can be retrograde; the Sun and Moon cannot.

The dates of a Sun sign shift by a day or so from year to year, because a year is not a whole number of days and the calendar catches up with leap days. That is why the dates are always given as "about". Someone born within a day of a boundary needs the time and place, not just the date, to know which side the Sun was on.

What a person is for

Not mood (that is the Moon), not manner (the Ascendant): the Sun is the thing a person keeps returning to when nothing is asking them to, the center they are built around. A Sun sign describes how that center works: a Capricorn Sun builds the thing slowly and signs it; a Gemini Sun is most itself halfway through an explanation, with a second one queued.

Sign for the how, house for the where

By sign, the Sun says how the center operates. A Leo Sun hosts: the dinner is at their place, the toast is theirs, and the chairs are set so they can see everyone. The same function in Virgo runs the kitchen and skips the toast.

By house, the Sun says where the center is spent. A Sun in the 6th puts the person's sense of themselves into the work itself: they are most at home with a task half done and a list beside it, and a holiday makes them restless by day three. A Sun in the 10th does the same work where it can be seen.

A Sun transit lasts a day or two

Because the Sun crosses a degree a day, its aspects to a natal chart are exact for a day and felt for two. That makes the Sun one of the five fast bodies this site reads in the daily horoscope, alongside the Moon, Mercury, Venus and Mars; the longer transit reading uses the five slow planets, Jupiter to Pluto, whose aspects hold for months or years. Once a year the moving Sun returns to its natal degree: that is the birthday, and the day the attention comes back to the person's own center.

See Sun in your own chartA free birth chart, with the reading, from your date, time and place.

Questions

Is my Sun sign the same as my zodiac sign?: Yes. When someone says their sign, they mean the sign the Sun was in on the day they were born. The rest of the chart adds the Moon, the planets and the houses, which is why two people with the same sign can be unalike.
Why do some sources give different dates for a Sun sign?: The Sun enters each sign at a particular moment, and that moment lands on a different calendar day depending on the year and the time zone. Dates such as "about July 23 to August 22" are averages. A chart computed from the birth time settles it.
Can the Sun be retrograde?: No. Retrograde motion is an effect of the Earth overtaking or being overtaken by another planet. The Sun's apparent motion is the Earth's own orbit, so it always moves forward through the zodiac.