In the deer hunting community, there is a lot of focus on scent control and wind, but little discussion of thermals, which can subtly carry your scent through the woods. Thermals, or columns of rising warm air, play a significant role in deer behavior and movement. Learning how to hunt thermals can help you remain undetected and in the best possible position to encounter mature bucks this season.
- Thermals occur when the sun’s rays warm the ground and cause air to rise. This creates currents of warmer rising air.
- Deer use thermals to move and bed undetected by predators.
- Topography plays a major role in dictating thermals. Hilly terrain produces more defined thermals.
- If your stand is on a ridgetop, hunt that spot early. Transition to benches in the afternoon, then low as the temperature drops in the evenings.
- Pay close attention to big temperature swings which can impact thermal patterns.
- Utilize scouting information to access stands and hunt thermals without leaving scent trails.
- Adjust stand locations to account for shifting morning and evening thermals.
Understanding and properly utilizing thermals takes time and dedication. But the reward of staying downwind from even the wariest whitetail bucks makes it well worth the effort. Analyze the terrain, prevailing winds, deer patterns, and temperature changes to begin hunting smarter using thermals.
What Are Thermals and How Do They Work?
Before we dive into hunting strategies, it’s important to have a solid understanding of what thermals are and what causes them.
Thermals occur when the sun warms the Earth’s surface, causing the air directly above it to heat and rise. The warmer, less dense air rises while the cooler, denser air sinks. This creates columns or currents of rising warm air known as thermals.
As the morning sun warms the ground, thermals begin to form and the deer use them to aid their movement downwind. By mid-morning, the ground is hot enough to reverse the thermal flow, carrying scent upward instead of downward. Then as the evening approaches and the ground begins to cool, the thermals reverse again, allowing the deer to move into feeding areas undetected.
How Thermals Impact Deer Behavior and Movement
Whitetail deer rely heavily on their sense of smell to detect danger. They use wind and thermals to travel, bed, and feed while avoiding detection.
In the early morning hours, whitetails use the rising thermals to move downwind of their bedding areas to feed. The warmth from the day’s first light generates thermals that carry the deer’s scent high into the air away from where they are headed.
Deer also use thermals for bedding placement. They prefer to bed on north-facing slopes where the ground stays cooler for more extended periods, allowing them to remain concealed as the thermals change throughout the day.
As the sun sets and the earth cools in the evening, whitetails reverse their movement, allowing the falling thermals to carry their scent away from predators.
How Topography Impacts Thermals and Wind
To utilize thermals to your advantage, it’s essential first to understand how topography impacts their behavior. Thermals are more pronounced and easier to predict in regions with higher elevation changes.
In flatter areas, thermals can swirl in multiple directions at once and are far less predictable. In hill country, however, they form consistent updrafts and downdrafts that the deer take advantage of. You might think the southeast foothills aren’t big enough to affect thermals, but all it takes is a 50-100 foot elevation change.
Tips for Hunting Whitetails in Hilly Terrain
When it comes to finding and patterning hill country bucks, thermals must play a prominent role in your decision making. Here are some tips to maximize your success:
The key to morning thermals is to hunt high. Set stands on ridgetops and saddles when hunting hilly areas. As temperatures rise later in the morning, thermals carry scent upward, taking your odor away from bedded bucks below. Hunting the high country above their bedroom allows you to remain undetected.
Follow the Benches
Long benches, especially those running east to west, are whitetail freeways during the early morning hours. Hunt stands placed 75-100 yards downwind of the bench to intercept deer as they use the rising thermals to move unnoticed.
Watch the Weather
A cold front or storm can change deer behavior overnight. Cool wet weather weakens thermals, which keeps deer bedded longer. Be flexible and don’t expect normal deer patterns during weather changes.
Use the Terrain
Funnel deer movement by placing stand sites near steep ravines, brushy draws, and saddles. Thermals swirl in these terrain features, allowing you to stay undetected even if not in the perfect wind direction.
Focus on Food Sources
Hunting over food sources along the edges of valleys, benches, and ditches allows you to intercept deer traveling undercover to feed. Place stands downwind as the evening thermal sink occur to catch them by surprise.
How to Hunt Cool Morning Thermals
My favorite time to take advantage of thermals is during the cool early morning hours. Here are some tips to maximize your effectiveness:
Scout and Plan Travel Routes
I spend extensive time scouting in the off-season to map out deer trails, funnels, and staging areas. I can then plan access routes that use thermals to pull my scent away from deer.
Set Up on Thermal Boundaries
Look for transition zones between benches, ditches, timber lines, and bedding areas. Before light, set up just downwind of these thermal boundaries to intercept deer using them as corridors.
Identify Bedding Areas
Locate bedding areas and then hunt 100-150 yards downwind of them in travel corridors. Study the terrain to determine likely connection points between bedding and feeding areas.
Consider Wind Direction
The wind often swirls in the morning. Make sure you can hunt multiple wind directions from your stand site. Thermals carry scent, but a direct wind can blow your odor right to the deer.
Adjust to the Conditions
Every day is different. Arrive early, use scent spray liberally, and wear rubber boots. Adjust stand placement if the wind changes. Be mobile and smart about wind currents.
How to Hunt Evening Thermals
Here are some tactics I’ve found effective for hunting whitetails during the evening thermal transition:
As air cools in the evening, thermals reverse, carrying scent downward. Hunt ditches, hollows, and valley bottoms to intercept deer moving downwind of you.
Watch the Temperature
Cooler temperatures mean weaker thermals and less deer movement. Warm evenings switch deer movement on as they ride the sinking air back to bedding areas.
Adjust Stand Locations
You can’t hunt the same stands morning and evening due to the thermal shift. Make sure you have stands for both periods of transition.
Use the Terrain
Place stands where deer naturally funnel through saddles, along creek bottoms, benches, and staging areas. Thermals will carry your scent away along their travel corridor.
Time the Approach
Wait until the last minute to access evening stands so you don’t leave a scent trail. sneaking in during the final 30 minutes can help avoid detection.
Final Thoughts on Hunting Thermals
Learning to hunt deer using thermals takes considerable time and observation. But thermals can make or break your hunt, especially during the rut and late season when bucks are most wary.
Here are a few final tips for better understanding thermals:
- Scout heavily and record wind direction during different times of day. Take notes on whitetail movement and sightings.
- Observe smoke columns and wind sock behavior when entering and exiting stands.
- Thermals sometimes flow opposite of the actual wind direction, so don’t exclusively use the wind as your guide. Watch your scent streamers closely.
- Buy a wind meter to accurately read wind speed and direction. Record daily data.
- Don’t overhunt stands. Leave them alone for extended periods to allow scent to dissipate.
Hunting thermals effectively is challenging but extremely rewarding. Use these tips to better locate and pattern mature bucks on your hunting property this season.
I get a lot of questions from newer hunters looking to improve their skills. If that’s you, I put together a list of answers to some of the most common questions I receive about thermal hunting:
What exactly are thermals and how do they work?
Thermals occur when the morning sun begins warming the Earth’s surface. The air directly above the ground heats up and rises, creating columns or streams of warmer rising air known as thermals. It’s just basic physics – the warmer air is less dense than the surrounding cooler air, so it lifts up.
I look for telltale signs like leaf movement and smoke direction right before dawn to start identifying thermals as they begin to form. Using an odorless wind indicator is another good way to observe thermals in action.
Why are thermals so important for deer hunting success?
Deer use thermals and wind currents to move, bed, and feed while avoiding detection. Thermals allow them to move downwind, away from danger, without spooking other deer and predators. Learning to hunt along the edges of thermals by predicting deer movement gives you a real leg up.
For example, in the mornings I position stands downwind from bedding areas along likely travel corridors between bedding and feeding sites. Then in the evenings, I transition to stands placed below saddles, benches, and valleys to intercept deer as thermals fall.
Don’t deer just move based on the prevailing wind direction?
Many new hunters believe checking the forecast wind direction is enough to predict deer movement. But you need to look at how thermals can influence the wind at ground level.
Often the wind is swirling while consistent thermals continue flowing. The interaction of variables like temperature, terrain, vegetation, and jet streams means the wind on the ground can differ significantly from weather reports. Thermals rise and fall regardless of wind speed or direction.
How long does it take to become an expert at hunting thermals?
It takes most hunters years of scouting, record keeping, and stand time to become advanced at using thermals. Personally, it took me the better part of a decade before I felt like the light bulb fully turned on. But I’m still learning new tactics every season.
Recording air temperatures, wind direction, and deer sightings each time you go out is crucial. Review your data over the offseason to gain insights. There are no shortcuts to truly mastering thermals – just time spent observing and lots of boot leather burned in the deer woods until patterns emerge.
What general tips do you have for newcomers?
Be patient and don’t get frustrated. Make thermals a focus of your scouting and preparation. Spend time glassing transition zones at dawn and dusk. Use wind indicators like smoke, streamers, and sock direction diligently.
Also, check out our article for beginner deer hunters for more advice on your first hunt.
Remember that hunting mature whitetails is an endless learning process. Stay humble, keep asking questions, and APPLY what you learn in the field. Consistent action is the only path to consistent success.