“Summertime and the livin’ is easy,” wrote Ira Gershwin and DuBose Heyward for George Gershwin’s aria in the 1935 opera Porgy and Bess.

That languid piece makes you want to kick back and not even want to attend a meeting, let alone wonder how you’ll dress for it.

When we start our day, can we assume that the prospect we are meeting for the first time will opt for comfort, versus a business look?

The answer is simple. No.

As we slog through hot days, we are reminded that business goes on and the rules of engagement don’t change, especially when networking or meeting a specific prospect for the first time.

You may say, “Can’t I give myself a break and dress for comfort when the humidex is approaching 40? “

Research has confirmed that someone forms an impression of us within 15 seconds of meeting us. In “The Definitive Book of Body Language”, Allan and Barbara Pease describe first impressions as “the love-at-first-sight” of the business world. They report that after 15 seconds, “you don’t get a second chance to make a first impression and that your approach, handshake, and overall body language are the key factors in deciding the outcome (of the meeting).”

I’d like to add attire to the list for three reasons.

The way you dress indicates your respect for the person you are meeting.
Dressing well confirms your self-esteem, confidence and sense of decorum, not to mention your ability to dress properly.
We are highly visual animals and what we see initially has a greater impact on us than what we hear. When we see a person with polished shoes wearing a well-cut suit or dress, we assume they are detail-oriented. (Who wants to work with someone who lets details slide?)

What happens if you are meeting on the weekend or in a casual environment? You can still look professional without appearing to be off to a formal wedding.

The casual wear debate

In Silicon Valley, the attire mandate among successful entrepreneurs (and not-so-successful entrepreneurs) is ‘less is more.’

Worn t-shirts, jeans and runners are considered acceptable as it’s all about one’s decision to reject traditional business decorum and let one’s individuality come through. Business people who try to emulate the Silicon Valley style beyond the Valley may quickly feel out of place in more conventional business situations, especially if they don’t work in the IT or entertainment industries.

Here are some tips for casual wear selection when meeting a prospect away from the office in stifling weather. You could be meeting them at their home around the pool or at a casual restaurant on a weekend.

Men’s Casual Wear Tips

Good: Tailored trousers, shorts and golf shirts with collars are acceptable. Dress jeans: if they flatter you.

Back to the closet: Warm-up suits, sweatshirts, sleeveless shirts, unclean, torn sneakers or flip flops. Any apparel with slogans or commercial messages.

Women’s Casual Wear Tips

Good: Dress shorts, attractive jeans, skirts and attractive sandals or pumps are always a good bet.

Back to the closet: Warm-up suits, sweatshirts, unclean, torn sneakers or flip flops and over-the-top purses or handbags. Any apparel with slogans or commercial messages.

You will never go wrong by dressing in a way that shows respect for others, as long as you don’t go over the top with your sartorial splendor, which can be distracting and unsettling.

When going to a business meeting, it’s best to assume the person will be dressed for the occasion, regardless of the climatic conditions.