Here’s why you might need to act fast if you want that big promotion this year

Suzy Welch: The two G's guaranteed to get you promoted

Instead of taking a vacation this August, try angling for that promotion you've wanted instead.

A report from workforce analytics company Visier shows that more employees get promotions in the summer than in the winter. The fall and winter months reliably had the lowest promotion rate, according to the report.

Visier analyzed an aggregated database of 3.5 million employees from over 70 companies that use its service to better understand its workforce, one that includes a range of companies such as healthcare, financial services, manufacturing and retail. The study considered upward movement in the company, like a title upgrade, to be a promotion. Getting a raise without a title change wasn't considered a promotion by the researchers.

According to the report, the rate of promotions increased by about 1 percent in the summer months. While a 1 percent change might not seem significant, at this report's scale it meant promotions for about 35,000 employees.

2 things you can do to get ahead — without looking overly ambitious

Promotion opportunities decline in the fall and winter, according to Visier's data, thanks, in part, to fiscal calendars, as companies determine budgets and find last-minute business opportunities before the end of the year.

Visier found that HR departments tend to use the summer to make internal hires, or promotions, rather than spending money and time to look for an outside candidate.

The number of resignations is higher during the summer months as well. "We may be seeing a reaction of offering promotions to retain employees, or promotions going to existing employees who replace those who resigned," Visier chief strategy officer Dave Weisbeck says.

Since a summer slump can make companies less focused on meeting business goals, young workers can use this time to prove themselves and stand out, according to Weisbeck. Best-selling author and CNBC contributor Suzy Welch says getting promoted happens when you over-deliver on your job, not just do it. This means finding solutions, not just problems, becoming a go-to person for key projects.

Don't forget to advocate for yourself as well. Keep a log of compliments and positive feedback and check in with your manager about your goals and what you can contribute further to the team. Even if you don't get that new title this month, you'll be that much closer.

Clarification: This story has been revised to reflect that these findings resulted from a Visier database analysis.

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