Is there a special uniform or dress code for priests?

Yes. It depends on the situation and the circumstance.

In liturgies such as Masses, Baptisms, Funerals, Weddings, Anointing, Liturgies of other kinds, the priest wears his vestments. These vary in type and colour depending on the event and location and the occasion or the time of the church year.

Some have asked, why do priests wear vestments that seem to be so different from the type of dress people wear in the year 2002, why can’t they wear a suit and tie like others. The reason is this:

Firstly it connects what we are doing today to a tradition that goes back thousands of years. Even though styles and even vestments have varied through the centuries, there is some value in visually connecting with that tradition. What happens in our liturgies (as St. Augustine once said) is something ever ancient and ever new!

Secondly, although our religious ceremonies always must relate to our life in the world and our liturgies always finish by effectively sending us to back out into the world to love and serve the Lord, there is also an element of the "transcendent" that we experience in liturgy. Vestments are a sign that what is going on is deeply human as well as touched by the divine and that which goes beyond the here and now. Wearing "ordinary civvies" would probably only pick up the here and now and dampen the "otherness" of our experience of liturgy.

Thirdly, most of the vestments in our liturgies are beautiful, graceful and free moving objects that serve to enhance movement and gesture. We should never be embarrassed about the use of symbol, movement and gesture in our ceremonies, since they are deeply human elements. I would actually not be in favour of the Presider wearing a "suit and tie" in a ceremony because as far as I am concerned that is restrictive of movement, and limits one to the norms and standards of present day fashion and culture and its hard to know why this would be better than symbols that express freedom and graciousness. The church, whilst not wanting to be separate from the world and present culture, is not a slave to the standards and restrictions of present culture either. Those who advocate this minimalising of symbols seem to be unwittingly part of a form of dampening of religious symbolism and expression. Symbols matter!

What is the daytime uniform of a priest?

This varies depending on region, culture and occasion.

In Brisbane Diocese, priests in formal occasions may wear distinctive cross on the lapel or on the tie, with a coat. Naturally, the priest may also wear the clerical collar with coat. Less formal situations might be either a white shirt with crosses on the lapel, tie or, if an open-neck shirt, perhaps crosses on the lapels.

In less formal situations, a short or long sleeve office shirt with open neck is very suitable. In no way should a priest dress in a way that reflects an unwillingness to be identified in the role and function he performs. The role of priest is something to be considered with respect and dignity.

There are different schools of thought  about whether priests should be recognisable publicly as priests by a distinctive uniform. There are good arguments on both sides to this. One might suggest that it is fine to have some recognisable sign that a person is a priest, because this can be a public witness and sign to others (both Catholic as well as the wider population) of the continuing relevance and presence of priests and the value of the vocation. There are cultural reasons why this distinctive visual identification might not necessarily be the traditional clerical collar. This can be experienced by some Australians, especially many young people, as a barrier rather than an aide to communication.

Also, priesthood is considered to be one of an inner state as well as an outward public vocation. Thus, one could argue that a priest who is comfortable with his identity as a priest and very much believing in his inner disposition towards priesthood, might not need to always wear outward signs of his office and character. The important thing in all this is that the priest, in the different situations he finds himself in, can both be comfortable in his identity as a person and a priest and also dress appropriately for the different ministry situations he finds himself in.