• Insider asked interior designers which trends are in and which are out this season.
• Pastels, natural materials, and floral window treatments are popular.
• Rustic designs and all-white interiors are becoming outdated and less trendy.

Pastel palettes are in

Aaron Lebowski, an interior designer and consultant at Juliei Salone, said this summer is all about bringing pastel colors into your space.

He said colors like pink, yellow, and blue bring to mind summery images, like sunny days and pool parties.

Natural materials are making their way indoors

Kate Diaz, interior designer and cofounder of Swanky Den, said we'll see more natural materials in design choices this season because they "bring the outdoors in.'"

"Wood, stone, and leather are going to be big this summer," Diaz said.

Floral window treatments are back and better than ever

Florals are no longer just a trend of the past, according to Courtney Wollersheim, interior designer from FLOOR360.

"'Grandmillennial' or 'grandma chic' is sneaking into many room styles as the summer season heats up because you need lots of florals and bold colors to achieve this look," Wollersheim explained.

"It's very on-trend to recreate the comfort and coziness of grandma's traditional style house with vintage pieces and floral fabrics for window curtains."

When incorporating florals, Wollersheim recommends mixing and matching tablecloth and window-curtain fabrics that are within the same color family.

Indoor greenery is also a big seasonal trend

Paige Anderson, interior-design architect at Nitido Design, told Insider that greenery is the key to sprucing up a space this summer.

Arch-shaped elements are having a moment

Catherine Staples, lead designer at Aspen & Ivy, told Insider arches are a "timeless" trend you'll see more of this season.

"From doorways to windows to mirrors and millwork, arches are a warm, whimsical way to elevate your space off the linear path," Staples said. "I expect to see arched elements in design this summer in furniture as well."

On the other hand, tons of reclaimed wood is a trend of the past

"The appeal of reclaimed wood kitchen tables, dining tables, chairs, coffee tables makes sense because it brings character and texture to any room," Wollersheim said.

But in recent years, she said, people are realizing there's such a thing as too much reclaimed wood in a space.

Wollersheim recommends keeping one of your favorite pieces and contrasting it with glass accents and soft-cushioned chairs for a more holistic look.

The formerly trendy 'rustic' style is taking a backseat

Known for its natural-looking aged look, the rustic interior-design style is on its way out.

"It's not that the rustic look is inherently bad, but the proliferation of it in homes can be overwhelming," Lebowski said.

He said you can find balance by having one or two rustic elements in your home, but you might not want to overdo it.

Shiplap is falling out of favor

Shiplap, wide wooden boards commonly used as part of the modern-farmhouse style, will start to see itself out, Staples said.

She said you will still see it appropriately used in coastal or period styles, but other trends will take the stage instead.

Still, she noted, some trends — including shiplap — are cyclical and may rise in popularity once again.

Colors will replace all-white interiors

Toussaint Derby, a lead designer at Havenly, said sleek, all-white interiors are going to be replaced with colorful ones.

She told Insider "the all-white aesthetic may have felt a little too cold and impersonal" so it's falling out of favor as people try to cozy up their spaces.

Monochromatic spaces aren't as popular anymore

According to luxury interior designer Margarita Bravo, monochromatic spaces just aren't as welcoming as other design choices.

"People are spending more time in their homes, and they want a more welcoming, inviting space with the use of different materials, textures, and accent colors," Bravo said.