Upper class...Suit and tie or at least a sport coat.

Middle class...dress shirt and pants.  Same goes for starter homes.

Looking at wooded and open land...CLEAN Blue jeans and a decent shirt.

Farm land...Decent shirt and boot like shoes.

Dairy farm...I wear Blue jeans and a decent shirt.  Something that I don't have to worry about getting dirty if the situation calls for it.

Neat and clean business casual. On some occasions, a suit and tie are appropriate.

Casual dress, though many wear suits or sports jacketts when listing

Depends on the property of course but when Im doing rentals in Summer here in AZ (which is usually 7-9 months long) I dress in shorts and company t-shirt / polo and company ball cap.  When showing horse property Ill wear boots and jeans incase I come upon a scorpian or snake-then a second pair of underwear is usually in order in that instance. which I keep neatly folded next to my bite and first aid kit in the jockey box of my pick-up.

Tallahassee, Florida is business casual.  The only people who wear suits are attorneys, politicians, bankers, and defendants.

Having said that... I wear a coat and tie... I can quickly shed the coat and tie, and roll up my sleeves if I am too "over-dressed" for the customer/client/situation.

We wear dress pants with logo shirts.

This area leans more to the casual attire.

I am usually business casual ... I need to be comfortable. I'm am not what I wear.  I am clean and well manicured ... that is what's important to me.

Raymond, our area is rather informal.  Most agents seem to go business casual.

We are very casual in my area. Today I wore a somewhat faded pair of jeans, a nice top and sandals. 

casual business attire.... but when working land and developments, construction boots and jeans.... always in the muck and myer....

I'm not saying everyone should wear a suit and tie but I do remember seeing a realtor in shorts and flipflops in the office. Even though it was a nice summer day I didn't view it as being a professional. Nice casual works every time in my book!

I don't think there's a norm.  Some wear suit and ties while others are in shorts and polo shirts.

Tommy Bahama or similar resort wear.

Our agents look like the general public so some wear jeans and flip flops, shorts and tee shirts and others wear business attire and everything in between. If you saw one without a name badge you would never know if that person was an agent or not.

At least business casual if a hot day. If cool, then I wear a tie and at least a sport coat, or suit.

I love dresses - so when the weather is warmer (Spring, Summer, Fall) I typically wear a dress with a sport coat.   We request the agents in our office to wear suits/ties for settlements and initial meetings and business casual for all other appointments.

Neat and Clean. Very rare to see a suit and tie though...

The norm is all over the place. There are some in suits ties, skirts and high heels! Then there are others who show in blue jeans and sneakers. I always ten to wear a suit or similarly professional outfit when first meeting clients. After that, I dress down for inspections and quick drop offs of paperwork.

Business casual is the typical dress in the Maryland suburbs of Washington, DC. Agents tend to be more dressy when working with high end properties.

It is sad to report that some agents present a very poor image for the real estate industry.

I dress in business casual clothes most of the time unless I am going on  a listing appointment, showing homes or at an open house. 

Business casual

I like William Feela's answer and philosophy.

Good answers here.