NEW YORK (TheStreet) -- Wearing unprofessional or overly revealing attire to work during the summer can ruin your professional brand. No matter how hot it gets, donning cooler clothes isn't worth jeopardizing your career. Our experts weigh in with seven of the biggest summer office wardrobe mistakes:
1. Wearing your sweats before you leave for vacation or the gym
If you're putting in a half-day or leaving for the beach after lunch, don't wear casual clothing to the office in anticipation of your next stop. Your boss and clients don't know what your plans are -- they just know you look unprofessional.
"Just go the extra mile and bring a change of clothes," says Brittney Levine, style and trend expert. "It doesn't make sense to spend a few hours at the office not polished, not looking your best, just because you have another engagement later in the day."
The same goes for people who are running to and from the gym, Levine says. Spending an hour or two at the office in your gym clothes is never something you want to do.
"Plan ahead and bring a change of clothes. Don't wear your sneakers all day, don't wear your flip-flops all day. The office is the office, not a gym."
2. Wearing graphic T-shirts that make too much of a statement
"You want to be in style, but you don't want to be sitting in the conference room wearing a T-shirt that says, 'Don't worry, Beyonce,'" Levine says.
Graphic T-shirts may be a bigger hazard for men, as many sports shirts and concert T-shirts men wear are far too loud, controversial or "aggressive" for the office, she says. Unfortunately, they just make you come across like you're "trying too hard" to be fun-loving or funny.
"Please do not show up in a shirt that talks about drinking or aggressively beating another sports team," she says. "Even if it's casual Friday, you can't show up to work in a shirt with foul language or anything that would make your colleagues do a double-take."
With that said, if your office encourages team spirit on a particular day, don't be afraid to show your colors, says Stephanie Menchaca, manager of HR services for Insperity.
"Clothing with slogans, messages or sports logos is generally frowned upon, but one exception is a day specifically designed for employees to show their spirit for a certain sports team or cause," she says.
3. Wearing weekend clothing to the office
So many professionals look at their summer wardrobe and think, "I could get away with wearing this on a Thursday or Friday," Levine says.
"But Thursday and Friday are still workdays. They aren't the weekend, and you could have important meetings those days as easily as you could on a Monday or Tuesday," she says.
Even if your office has a casual-dress code, you must accept that you are going to need two wardrobes if you work in a professional environment -- work and weekend, Roccia explains.
"If you're limited from a budget perspective, be sure you pair your appropriate weekend garments with more tailored or professional pieces like a blouse or season-appropriate blazer," she says.
4. Not knowing your company's dress policy
Every company interprets "business casual" or "summer casual" differently, based upon the company culture and work environment, says Amanda Augustine, job search expert for TheLadders.
"Look for clues from senior management," she says. "If you're questioning your outfit, talk to your HR department first before you wear it to the office."
Review your company's dress policy and make sure you're clear on what is acceptable -- if you're not clear, you should ask, says Michelle Roccia, EVP of employee engagement for recruitment firm WinterWyman.
"You don't want to be embarrassed by being asked to go home to change," she says.
It's always better to overdress than underdress -- so when in doubt, dress up not down, Roccia says. Also, remember to consider your particular line of work and the people with whom you interact.
5. Wearing fabrics that are too sheer
Summer fabrics such as cotton and linen are attractive and appropriate, as long as they don't wrinkle too much or show too much, Roccia says. If you go with white and other light colors, be sure the pieces are lined so they do not reveal too much. Anything that reveals even a hint of lingerie or a bra should be avoided at all times.
"This summer, sheer fabrics are a huge trend. Anything sheer, lace or crochet is big, but rarely are those items appropriate for the office," Levine says. "If you can see your bra, then you need to leave that top in your closet for the weekend."
With the weather heating up, many women will naturally gravitate toward garments that are cooler and lighter weight, and may not realize they are inappropriate. Before you leave the house, give yourself a long look in the mirror.
"You may feel like you're completely covered up, but the outline of your bra will be showing. You can't walk into a meeting like that," she says.
6. Exposing too much skin
For women, the biggest risk of a summer wardrobe is over-exposure, Augustine says.
"Avoid clothing that reveals too much skin, such as halter tops, skimpy tank tops, plunging necklines and short or curve-hugging skirts and dresses," she says. "Stick to structured, sleeveless dresses or belted shirt dresses with knee-length hemlines, and trade your high heels for leather sandals, wedges or ballet flats."
Strapless tops are probably best left at home during the workday, Menchaca adds.
"Even tank tops should be worn with caution, and usually with a cover-up. That doesn't mean every top has to have sleeves, but it should be fairly conservative," she says.
Also, anything that reveals a bra strap or back of a bra -- such as a spaghetti strap top -- should be avoided.
"Not even the most casual work environments would find that appropriate."
7. Wearing shorts or flip-flops
Even if your office has casual Fridays, it's never a good idea to wear shorts -- and that goes for men and women, Roccia says.
"Shorts are never appropriate for an office," she cautions. "They are inherently casual and do not convey professionalism. The more your skin shows the more casual you appear."
When it comes to flip-flops, Levine says that although women can get away with an occasional dressy flip-flop style sandal at the workplace, men can't.
"Guys just can't get away with flip-flops at any time, especially not with dress pants," she says. "Nobody needs to see your toes."