Climate scientist Sarah Kapnick, PhD, grew up in Chicago and got married in her home city on an August day. But research Dr. Kapnick has been conducting on worldwide weather patterns suggests that her one-and-a-half-year-old daughter, should she choose to wed in Chicago once she's an adult, likely won't pick August as her month. It will be too hot. The study she recently concluded — the first of its kind, as climate science normally looks at averages like global temperature, and weather extremes, like droughts and blizzards — predicts a significant drop in mild-weather days in the next 100 years, with dramatic declines in some parts of the world. Dr. Kapnick and two other scientists examined how mild-weather patterns are expected to change due to the buildup of human-caused greenhouse gases in our atmosphere. (Scientists define mild weather as between 64 and 86 Fahrenheit.) Published last week in the journal Climatic Change , the research projected that worldwide, the number of mild days will decrease by 10 to 13% by the end of the century. The current world average of 74 annual mild days will drop by four days by 2035 and 10 days by 2081 to 2100. The hardest-hit areas are expected to be in Africa, Asia, and Latin America — while some colder regions, like parts of Canada, will actually see an increase in mild days. Dr. Kapnick, a research scientist at the National Oceanic and Atmospheric Administration, says that one of her biggest motivators for conducting the study were her friends and family. Because of her profession, when people in her inner circle get engaged they often ask her questions like, "So what's the weather in Florida going to be like in November?" "I can't tell you what the weather will be like on a precise day," she laughs. What she can say, based on these new findings: Many parts of the U.S. will experience hotter summers in the coming decades. And while we can't stop the ravaging forces of climate change, we can control when and how we plan our events. Based on our knowledge about shifting mild-weather patterns, we can make more informed decisions about the future. For wedding-planning, this could mean some creative rearranging, like choosing a spring or fall date instead of the popular summer weekend. "We can help you pick a wedding date now and also let you know where you may be planning your daughter's wedding in a few decades," says Dr. Kapnick. "For example, the model projects that there will be more mild-weather days in the fall and spring in NYC, but fewer days during the summer-wedding season." It could also mean planning your event in a milder part of the country — say, the Rockies instead of swampy Washington, D.C. — or even just carefully considering air-conditioning, shade, and water options. On the East Coast, especially, a loss of mild-weather summer days will bring higher humidity — which, Dr. Kapnick notes, could ruin your hair and makeup for a special event; something to consider when booking a beauty professional. There are, undoubtedly, larger personal implications than your wedding day: Major weather shifts could affect your physical or mental health, contributing to stress. “Predicting changes in mild weather is not only important to business and industry, but can also contribute to research on the future of physical and mental health, leisure, and urban planning,” notes Dr. Kapnick.