When Do Snakes Come Out in Wyoming? Seasonal Activity, Species, and Safety Tips

Wyoming’s wide-open landscapes, sagebrush flats, and rocky canyons create ideal conditions for snakes — and if you spend any time outdoors here, chances are you’ll eventually cross paths with one. Knowing when snakes are active, which species you might encounter, and how to respond calmly and safely can make all the difference between a startling moment and a dangerous one.

Whether you’re hiking in the Bighorns, camping near the Green River, or simply spending time in your backyard, this guide walks you through everything you need to know about snake activity in Wyoming — from the first warm days of spring through the final retreats of fall.

Key Insight: Snakes are ectothermic, meaning they rely entirely on environmental temperatures to regulate their body heat. In Wyoming’s cold-winter climate, this makes temperature the single biggest driver of when snakes appear and disappear each year.

When Snake Season Starts and Ends in Wyoming

Snake season in Wyoming follows the rhythm of the state’s climate — short, warm summers sandwiched between long, cold winters. There are seven species of snakes in the state that give live birth, and that adaptation helps their survival in areas such as Wyoming where there is a short season before the cold-blooded creatures need to head for a den before winter arrives.

In general, most snake species in Wyoming begin emerging from their winter dens in mid-to-late April, once daytime temperatures start climbing consistently above 50–60°F. Activity picks up through May and reaches its peak during the warm summer months. In Wyoming, the active season for many species generally extends from late April or May through September, coinciding with periods of maximum prey availability.

By October, as nighttime temperatures drop, most snakes begin retreating to their overwintering sites. In Wyoming’s continental climate with cold winters, snakes must enter a period of dormancy known as brumation to survive, and they typically retreat to underground hibernacula in September or October as nighttime temperatures consistently drop below their activity threshold.

Snake season in Wyoming therefore runs roughly from April through October, with the most active window falling between May and September. At higher elevations, the window is even shorter, as temperatures remain cooler well into spring and return to cold earlier in fall.

Pro Tip: Even during “snake season,” cold snaps can temporarily push snakes back into cover. The days immediately after a cold spell — when temperatures rebound quickly — often see a surge in snake activity as they emerge to warm up.

Peak Snake Activity Months in Wyoming

While snakes can technically be encountered any month from April through October, activity is not evenly distributed across that window. Understanding the peak months helps you stay alert at the right times of year.

May and June mark the beginning of peak activity. Snakes emerge from hibernation hungry and actively searching for food and mates. This is when you’re most likely to encounter them crossing roads or basking on warm rocks and trail surfaces in the morning hours.

July and August represent the hottest stretch of Wyoming’s summer. During these months, Wyoming snakes are most active in the early mornings or late evenings during the summer, and are also active at night and generally come out in cooler weather. During the heat of midday, most snakes seek shade under rocks, logs, or dense vegetation.

September brings a secondary period of visible activity as snakes feed heavily to build fat reserves before winter. Temperatures cool enough that snakes may be active throughout more of the day rather than just at dawn and dusk.

The Plains Garter Snake is considered one of the most cold-tolerant of all snakes, and will even come out of hibernation on warmer winter days. So while October is the general cutoff, a warm late-fall afternoon can occasionally bring a snake out even after most species have denned up for the season.

Common Snake Species in Wyoming and Their Active Seasons

Wyoming Game and Fish reports at least 14 species and subspecies of snakes are found in the state. The vast majority are non-venomous and play important roles in controlling rodent and insect populations. Here’s a look at the most commonly encountered species and when you’re most likely to see them.

You can find a comprehensive overview of all the types of snakes in Wyoming to help with identification when you’re out in the field.

Garter Snakes (Wandering, Plains, Red-Sided, and Valley)

Garter snakes are among the most frequently seen snakes in Wyoming. There are three garter snake species in southeast Wyoming — the wandering garter snake, the red-sided garter snake, and the plains garter snake — all small to medium sized, typically 20 to 30 inches long, and the wandering garter snake is common and found throughout the state, typically along rocky shorelines of streams and lakes.

In Wyoming, garter snakes are found in low prairie habitats below 6,500 feet, often near sloughs and riparian areas, and are active from late April into October, sometimes feeding at night during the hot summer months. The various types of garter snakes share broadly similar habits, though each has slightly different habitat preferences across the state.

Bullsnake (Gophersnake)

In Wyoming, the bullsnake is found in plains grasslands, sagebrush grasslands, sandhills, riparian shrub, marshes, rocky canyons, mountain foothills shrub, agricultural areas, and urban areas. Active from late April through September, bullsnakes are large, powerful constrictors that are often mistaken for rattlesnakes due to their similar coloring and defensive behavior of hissing and vibrating their tail.

Important Note: Bullsnakes are completely harmless and actually beneficial — they are one of the most effective natural controls for rodent populations in Wyoming. If you encounter one, give it space and let it go about its business.

Northern Rubber Boa

Northern Rubber Boas can thrive in diverse habitats in Wyoming, ranging from grasslands, meadows, and chaparrals to deciduous and coniferous forests and high alpine environments, but you won’t find this snake in hot and dry areas, as they cannot tolerate higher temperatures — the best place to find one is typically under shelter, such as rocks, logs, leaf litter, and burrows.

Western Milksnake

Western Milksnakes are found in parts of Wyoming in open sagebrush and grasslands and are occasionally seen in suburban areas, and they’re a secretive species frequently found under objects like rocks, logs, boards, and other debris. They are sometimes mistaken for coral snakes due to their banded coloring, but there are no coral snakes in Wyoming — the western milksnake is entirely harmless. Learn more about how to tell milk snakes and coral snakes apart if you ever encounter one.

Plains Hog-nosed Snake

The Western Hog-nosed Snake is active during the day but is most active in the morning and early evening from around late April to mid-October. This species is famous for its dramatic defensive display — it will flatten its head, hiss loudly, and even roll over and play dead when threatened.

Smooth Green Snake

Smooth green snakes thrive in moist meadows, grasslands with scattered shrubs, forest edges, and riparian areas where grass cover remains dense throughout the active season. Their slender, bright green bodies make them one of Wyoming’s most visually striking non-venomous species, though they are rarely spotted due to their excellent camouflage.

Venomous Snakes in Wyoming and When to Watch For Them

Wyoming has a relatively small number of venomous snake species compared to many other states. Wyoming is home to only two venomous snakes: the prairie rattlesnake and the midget faded rattlesnake. Both are rattlesnakes, and both follow the same general seasonal pattern as other Wyoming snakes — active from spring through fall, dormant in winter.

It’s worth understanding the difference between venomous and poisonous snakes — rattlesnakes inject venom through a bite, which is distinct from being poisonous. You can also explore the most venomous snakes in North America to put Wyoming’s species in broader context.

Prairie Rattlesnake

The prairie rattlesnake is the more widespread of Wyoming’s two venomous species. In Wyoming, the prairie rattlesnake has been found in prairie and mountain grasslands, desert and sagebrush shrublands, lower montane and xeric forests, riparian areas, rock outcrops, prairie dog towns, and agricultural and developed areas.

You can identify prairie rattlesnakes by their thick, robust body reaching 3–5 feet in length, with coloration ranging from greenish-gray to brown with darker blotches along the back, and the triangular head, narrow neck, and heat-sensing pits between the eyes and nostrils are telltale signs. They’re most active during warmer months when you’re likely to be outdoors, particularly in early morning and evening hours.

The prairie rattlesnake hibernates during the winter, often in communal dens typically found in rock crevices, caves, or old mammal burrows, and individual snakes return to the same den each winter and migrate up to seven miles to their hunting grounds in the spring.

Common Mistake: Many people confuse bullsnakes for prairie rattlesnakes. The key difference is the rattle — if you don’t see or hear a rattle, it is almost certainly not a rattlesnake. Bullsnakes will vibrate their tails in dry leaves to mimic rattling, but they have no actual rattle.

Midget Faded Rattlesnake

The midget faded rattlesnake is a small and highly venomous pit viper found in Wyoming, also known as the yellow or faded rattlesnake. This subspecies is found in rock outcrops in sagebrush desert communities, and its range is restricted to the lower Green River Valley from the cities of Green River and Rock Springs south to the Utah-Wyoming state line.

Midget faded rattlesnakes have one of the most dangerous and toxic venoms in North America, and their venom contains a potent and uncommon neurotoxin that attacks and destroys muscle tissue. In the state of Wyoming, they are regarded as protected, meaning it is illegal to capture, trade, or kill these snakes. If you encounter one, do not approach it — contact the Wyoming Game and Fish Department for assistance.

For a broader look at dangerous rattlesnake species, see the most venomous snakes in the US and the most potent snake venoms ranked by toxicity.

Where Snakes Are Most Commonly Found in Wyoming

Wyoming’s varied geography — from high alpine meadows to sagebrush desert basins — means snakes occupy a wide range of habitats. However, certain environments consistently attract more snake activity than others.

Rocky Areas and Outcrops

Rocks are prime snake habitat across Wyoming. They absorb heat during the day and release it slowly at night, making them ideal basking and shelter spots. Rattlesnakes like rocky areas, areas with lots of small mammals such as river and stream corridors and prairie dog colonies, and rock, wood, or other debris that provides cover during the heat of the day. The midget faded rattlesnake, in particular, is found in and around rocky cliffs, rockslides, and rocky desert areas.

Sagebrush Flats and Grasslands

Prairie rattlesnakes prefer rocky outcrops, sagebrush flats, and prairie edges — exactly where many hiking trails wind through Wyoming’s landscape. The eastern and southeastern parts of the state, with their open grasslands and sagebrush communities, support some of the highest snake densities in Wyoming.

Riparian Zones and Water Sources

Areas near streams, rivers, ponds, and marshes attract both the prey that snakes hunt and the snakes themselves. The common garter snake is found in plains, foothills, montane zones, and usually near permanent water sources. If you’re fishing along the Bighorn River, exploring Yellowstone Lake’s shoreline, or hiking near any creek corridor, be aware that garter snakes and even prairie rattlesnakes may be present.

Prairie Dog Towns

Prairie dog colonies are hotspots for prairie rattlesnake activity throughout the year. The prairie rattlesnake is often found in the grasslands and hibernates in the fall on mountain ridges, and they are usually found near prairie dog colonies where they feed on rodents and ground-nesting birds.

Trails, Roads, and Warm Surfaces

Paved and dirt surfaces retain heat well, making trails and roads common places to spot snakes — especially in the early morning and evening when snakes come out to warm up. Always watch where you step when hiking, and scan the trail ahead before placing your feet on or near rocks and logs.

Pro Tip: When hiking in Wyoming during snake season, stick to open trails where you can see the ground clearly. Avoid stepping over logs or rocks without first looking on the other side — snakes often rest in the shade beneath them.

What to Do If You Encounter a Snake in Wyoming

Most snake encounters in Wyoming are completely harmless — the snake wants to avoid you just as much as you want to avoid it. Snakes are not aggressive and avoid contact with humans if given the choice in most circumstances, and close encounters are usually just as concerning for the snake as they are for the person — hissing and aggressive behavior is the snake’s attempt to avoid conflict; it would prefer slithering away to having to strike.

If You See a Non-Venomous Snake

Simply give it space and let it move along. Non-venomous snakes like garter snakes, bullsnakes, and rubber boas are valuable members of Wyoming’s ecosystem, helping to control rodent and insect populations. There is no need to kill or relocate them. If a snake is in your yard, it will typically move on its own within a day or two.

If You See a Rattlesnake

If you come across a rattlesnake, do NOT try to move it or kill it — handling or attempting to kill a snake greatly increases your likelihood of being bitten. Instead, back off quietly and let the snake retreat. If the snake is on a well-traveled hiking trail, keep an eye on it from a distance and alert other hikers until it retreats off the trail.

If You Are Bitten

Wyoming’s venomous snakes are known for having potent venom, so if you get bitten, treat the situation as an emergency and contact emergency services immediately and stay calm. Here is what to do — and what to avoid:

• Stay as calm as possible and move away from the snake
• Remove jewelry or watches near the bite area in case of swelling
• Immobilize the bite area and keep it below your heart if possible
• Get to a hospital or call 911 as quickly as possible
• Wyoming hospitals stock antivenom, but time is critical

Do NOT do the following:

• Do not attempt to suck out the venom — the tall tale of sucking the venom out is not effective and could make things worse — it’s a total myth
• Do not cut the bite area or apply a tourniquet
• Do not apply ice to the wound
• Do not handle a freshly killed rattlesnake, as it can still inject venom

Important Note: Research shows that between 7,000 and 8,000 people are bitten by venomous snakes every year in the United States, and only five of them die. Approximately 25% of rattlesnake bites are considered “dry,” meaning the venom isn’t injected — but the bite still requires medical attention.

General Prevention Tips

• Wear closed-toe shoes or boots when hiking — never sandals in snake country
• Watch where you place your hands when climbing rocks or reaching into brush
• Be careful gathering wood or climbing on rocks, and never grab what you think is a stick or log while swimming, as snakes can swim
• Rattlesnakes tend to like cool, shaded areas, so it is best to stay aware in those environments
• Keep pets on a leash and away from rocky areas during snake season

For more context on how Wyoming’s snakes compare to venomous species elsewhere, you can explore venomous snakes in California, venomous snakes in Georgia, and venomous snakes in Florida. Wyoming’s two-species list is relatively short — but that doesn’t mean you should let your guard down during snake season.

Understanding when snakes come out in Wyoming — and how to respond when you see one — transforms a potentially alarming encounter into a routine part of enjoying the state’s outdoors. Rattlesnakes are an ecologically important species on the plains and sage deserts of Wyoming, and snakes keep rodent populations in balance and have benefits that cascade to many other plants and animals. With awareness, respect, and a few simple precautions, you can share Wyoming’s wild spaces safely with the snakes that call them home.