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How snowflakes get their distinct and various shapes

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February 5, 2026

Close-up image of a complex snowflake with a tiny, simple 6-petaled flake attached to one branch. — View at EarthSky Community Photos. | Tawnya Silloway in Colorado submitted this image on January 23, 2025, and wrote: “I was able to photograph many fluffy snowflakes yesterday, but this one stood out because it brought a daisy.” Thank you, Tawnya!

Exquisite crystalline snowflakes capture the imagination. But what is the science behind their formation. And is it true there are no two snowflakes alike?

First of all, the temperature and humidity of the atmosphere determine the shapes of snowflakes. And snowflakes form in the atmosphere when cold water droplets freeze onto dust particles. Finally, depending on the temperature and humidity of the air where the snowflakes form, the resulting ice crystals will grow into a myriad of different shapes.

Graph: temperature on X axis, humidity on Y axis, with different kinds of snowflakes. — Temperature and humidity determine snowflake formation. Image via National Weather Service/ NOAA.

Wilson Bentley

Wilson Bentley (1865–1931) from Jericho, Vermont, was the first person to capture photographs of snowflakes through a microscope attached to a camera. His collection of over 5,000 images – no two alike – introduced many people to the astounding diversity of snow crystals.

A man in a winter coat and a hat standing in front of a large, old-fashioned camera setup on a table outside. — Wilson “Snowflake” Bentley, who photographed over 5,000 snowflakes between 1885 and 1931. Image via Wikimedia Commons (public domain).

Nine snowflakes printed in white on black in shapes ranging from a flat hexagon to complex 6-branched flakes. — Snowflakes by Wilson Bentley showing a range of shapes. Image via Wikimedia Commons (public domain).

Classification systems

In 1951, scientists from an organization now called the International Association of Cryospheric Sciences (IACS) devised a classification system that characterized snowflakes into 10 basic shapes. Kenneth Libbrecht, professor of physics at the California Institute of Technology, in his guide to snowflakes at SnowCrystals.com, provides this chart of 35 types of snow crystals. They range from ice fragments to rods to the much more complex fern-like dendritic flakes we are all familiar with.

Chart with 35 drawings of different shapes from flat to rods to six-sided fernlike flakes. — View larger. | Here’s a chart from Kenneth Libbrecht’s SnowCrystals.com website that shows 35 types of snowflakes. Image via Kenneth Libbrecht. Used with permission.

How snowflakes form from water vapor

Libbrecht has made extensive observations of how water molecules get incorporated into snow crystals. In his research, he observed that the most intricate snowflake patterns form when there is moisture in the air. Snowflakes produced in drier conditions tend to have simpler shapes.

According to Libbrecht’s research, temperature also has a large effect on the formation of snowflakes. Snowflakes formed in temperatures below -7.6 degrees Fahrenheit (-22 degrees C) consist primarily of simple crystal plates and columns. Meanwhile, snowflakes with extensive branching patterns are formed in warmer temperatures.

Visit Libbrecht’s website SnowCrystals.com for a wealth of information about snowflakes, including short videos of lab-grown snowflakes forming.

Closeup of glistening, translucent snowflakes each with six feathery arms slightly clubbed on the ends. — Fiona M. Donnelly captured these snowflakes in Smiths Falls, Ontario, on January 3, 2018. Used with permission.

A gallery of snowflakes by Wilson Bentley

A snowflake with six delicately branched points. — A spiky dendritic snowflake by Wilson Bentley. Image via Wikimedia Commons (public domain).

Flat white hexagon with dark lines from center to corners. — A simple hexagonal plate snowflake photographed by Wilson Bentley. Image via Wikimedia Commons (public domain).

Snowflake with six delicate, complex branches. — A complex and delicate dendritic snowflake by Wilson Bentley. Image via Wikimedia Commons (public domain).

Snowflake with six delicate, bulbous crystal branches. — One of the snowflakes photographed by Wilson Bentley. Image via Wikimedia Commons (public domain).

Snowflakes from our community photos

Composite image of zoomed-in view of several snowflakes. — View at EarthSky Community Photos. | Eric Jensen captured these photos on February 28, 2026, from Virginia and wrote: “Taking advantage of the snowfall in Milwaukee to learn how to image snowflakes. It was a learning experience!” Thank you, Eric!

Closeup of a snowflake with six very complex, fir-tree-like branches, lying on dark knit cloth. — View at EarthSky Community Photos. | Judy Boyle in Whitehall, Montana, captured this image on January 7, 2024, and wrote: “I was taking my border collies for a walk, and it began to snow. I notice this uniquely perfect snowflake on the black fur of one of the dogs. Knowing he wouldn’t stand still for a picture, I carefully picked it off and put it on my glove.” Thank you, Judy!

Snowflakes: Closeup of a perfectly shaped snowflake on a green leaf. It has 6 fern-like arms. — View at EarthSky Community Photos. | Sheryl R Garrison in Southern Alberta, Canada, captured this lovely closeup image of a snowflake on November 9, 2022. She wrote: “Every winter I try to photograph snowflakes in honor of Wilson (Snowflake) Bentley, the first person to photograph a single ice crystal in 1885. While he would capture them on black velvet, I enjoy hunting for them on natural surfaces. This snowflake was photographed on a raspberry leaf. The temperature was -18 C [-0.4 F].” Thank you, Sheryl!

Did you capture a great shot of a snowflake? Submit them here.

Bottom line: Temperature and humidity influence the shape of snowflakes. The most intricate snowflake patterns form during warm and wet conditions.

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Posted

February 5, 2026

Earth

Deanna Conners

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About the Author:

Deanna Erin Conners is a biologist and science communicator from Western New York who has been contributing to the conversations on EarthSky since 2011. Her overarching hypothesis is that we have vastly underestimated the intelligence of non-human species. She is endlessly fascinated by the interconnectedness in nature and occasionally chimes in with stories about birding, Earth science, and the Great Lakes. (Portrait taken at Buckhorn Island State Park, NY, appears courtesy of Karen Lee Lewis.)

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