It doesn't even have to be drastic. As the weather changes from boiling hot to crispy cool, so can your hair — from blond beachy waves to buns and braids in rich shades of brown.
And if you're as addicted to the 'gram as I am, you're in luck. Instagram is not only the place to find out what your friends are eating for dinner or what their adorable children are doing, it's also the hot spot for the latest trends. That's right — Instagram is the hub for what is hot and fresh with the change of each season, whether you're talking hair, makeup or clothes. Even in the wake September's New York Fashion Week, The New York Times pointed to Instagram as the best place to find beauty inspiration. Instagram has become so trend-centric that some fashion bloggers are making up to $15,000 per post — just for promoting brands and hashtagging new looks.
But even for the expert-grammers — those who were born to double tap — hair trends can be hard to find if you don't know where to look. If you're not already following creative hairstylists on Instagram, you may completely miss these new fall hairstyles on your feed:
1. Autumn ombré
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Fantastic news for every woman who has a summer ombré staring back at her in the mirror: After all your hours (and money) spent at the salon to get your hair just right, you don't have to give up your trendy two-toned hair for the fall. You'll only need to update the beachy blonds in your ombré with darker fall tones to rock this season's #autumnombre trend.
More: How to create an ombre nail design
2. Braided topknot
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Back-to-school also means back to work for most of us. It's time to comb out that beachy summer hair and make your workday bun a little less "basic" with a trending fall topknot by Innersense Organic Beauty, a Certified Green Brand. The seemingly intricate topknot is actually deceptively simple when you start with hair in a loose braid.
3. Chocolate waves
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Innersense has their ear to the trending hoofbeats of Instagram. As a top women's hairstyle for the fall, Innersense says it's all about cascading bohemian waves in rich chocolate shades — made possible by a flawless blowout.
4. Fishtail braid
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Keep your hair nice and neat as the first cool front rolls in with the modern interpretation of the traditional fishtail braid. It should go without saying that autumn is also the perfect time to go auburn -- make your braid even bolder by transitioning to red from medium to dark brown.
5. Hair charm
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If you're not ready for a big fall hair change, dip your toes in the water with an adorable autumnal hair accessory. Hair jewelry, like the kind of fun and funky handcrafted stuff you can find on Etsy, is booming on Instagram this fall, making it easy to dress up your look without too much morning prep.
6. Hint of gray
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#GrannyHair was the Instagram rage earlier this year, but the shocking hair trend hasn't died off completely. Just in time for fall, Natural Root Sista debuted the most attractive way to go gray — instead of the full Granny — with a kiss of gray to complement your natural color.
7. Long angled lob
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Long angled lob are the only words you need to remember when you visit your stylist for your seasonal trim. Michelle Forst, celebrity stylist at George the Salon Chicago, calls this the "hot cut" of the season, moving from summer into fall. She says, "To recreate this trend cut, make sure that you ask your stylist to maintain length and keep the front slightly longer. This works really well with the bang because it elongates the face instead of shortening it."
8. Old-fashioned updo
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Every flirty fall fantasy you've ever had of picnicking on the lawn with Mr. Darcy can finally come true. With the change of the seasons, the hair classics are back — Mary Brambila of Brambila Salon in Santa Monica recommends the romantic, loose updo for weddings or a special night out.
9. Purple/blue enhancements
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Toni Washington of Atlanta's Toni Washington Hair Salon predicts colorful changes in the fall of 2015. If Washington's Instagram feed is any proof, we can expect to see more bright hues, like hints of blue and purple, woven into rich brown fall tones.
More: 7 Ways to color your hair without traditional hair dye
10. Rich brown color
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If you've been waiting for permission to darken your hair for the fall, the time is now. Washington posted a picture of rich brown tones interspersed with golden highlights as the ideal fall hair color combo.
11. Sleek side braid
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If Twitter is any indication — where, like Instagram, you can find new fall hairstyles with hair tutorials and pro tips posted in real-time — fall braids are trending. Twitter's top three braid hashtags for the season are ranked as #FrenchBraid, #FishtailBraid and #WaterfallBraid. With such a variety of braid styles out there, ranging from simple to complex, you can be as creative as you want to be. Start by trying Washington's side-swept side braid as part of your regular hairstyle, as seen on her Instagram model shot by Zina Franklin.
12. Tinker Bell topknot
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If you identify as an everyday bunhead, then this hot fall hair trend may make all your dreams come true. Inspired by Disney's Tinkerbell, #TinkStyle on Instagram is a fresh reinvention of the traditional topknot, most recently spotted on actress Bella Thorne on the red carpet at the VMAs.