Undersstanding Thermals and how they rise and drop during the day.

Understanding Thermals for Deer Hunting: How it Works

Understanding thermals for deer hunting can be challenging for even the best bow hunters. In this post, I am going to make it a lot easier for you and show you how it works. Deer have incredibly sensitive noses, and they rely on their sense of smell to detect danger and avoid predators. As a hunter, you need to be aware of how the wind and thermals are moving to avoid getting winded by deer. Now let’s take a closer look at thermals and how they can impact your hunting experience.

First off, it’s important to understand that when you talk about hunting using thermals, you must also take into account winds and wind direction. Both thermals and winds interact and affect the overall direction of the wind and this dictates where and how you hunt.

Once you complete reading this post you will be closer to understanding thermals, I highly recommend reading, “How to Hunt the Wind for Deer Scent Control,” here on our website to get a better understanding of how the two interact together and the best way to hunt them. This will give you a complete outline of how this type of hunting can be an integral part of your scent control routine.

Understanding Thermals for Deer Hunting

What Are Thermals?

Thermals refer to the movement of air caused by temperature differences. Warm air rises and cool air sinks, creating air currents that move up and down. These currents can be influenced by the surrounding terrain, such as hills or valleys, and can be affected by weather conditions like wind.

The most basic way to look at it is to understand that when the sun rises in the morning, the air is heated and rises causing thermal wind currents to rise. This continues throughout the day and changes as temperatures change. Once the sun begins to set, the air cools and begins to drop causing thermal air currents to drop. The effect this has on wind direction depends largely on the terrain in the area, natural and manmade obstacles, and proximity to water.

Sometimes thermal air currents rise, pulling air up. This effect can be seen when using wind-checking tools like milkweed where you can actually see it get pulled up into the sky when dropped. You then can see the opposite when thermal air currents drop, pulling milkweed to the ground. Sometimes you get something in between.

Dropping Milkweed to Check Wind Direction and Thermals
Dropping Milkweed to Check Wind Direction and Thermals

Hill Country Thermals

In hill country (or mountain areas), thermals are heavily influenced by the topography of the land. The cooler air tends to settle in the valleys while warmer air rises up the hillsides, creating an uphill thermal pattern in the morning. During the evening, the opposite occurs as the air starts to sink down the hillsides and into the valleys, creating a downhill thermal pattern.

When hunting in hill country, it’s important to understand the specific topography of the land and how it impacts the movement of air. Look for areas where there is a change in elevation, such as ridges, saddles, and benches, which can create natural funneling points for thermals. Pay attention to the direction of the wind and how it is being influenced by the surrounding terrain.

For example, if the wind is coming from the east and you’re hunting on the west side of a hill, you can use the uphill thermal pattern to your advantage by approaching a buck bedding area located uphill from your position. To see how a mature buck uses thermals to choose his bedding area in hill country, check this out.

Thermals rise in the morning and drop in the evening. This is the most basic tenant of understanding thermals for deer hunting.

Low-lying Area Thermals

In low-lying areas (like flats and river bottoms), thermals can also be influenced by the surrounding topography. During the morning, cool air tends to settle in low-lying areas, creating a downhill thermal pattern. In the evening, the opposite occurs as the air starts to rise from the valleys, creating an uphill thermal pattern.

When hunting in low-lying areas, it’s important to understand the specific topography of the land and how it impacts the movement of air. Look for areas where there is a change in elevation, such as creek beds, gullies, and ditches, which can create natural funneling points for thermals. Pay attention to the direction of the wind and how it is being influenced by the surrounding terrain.

For example, if the wind is coming from the west and you’re hunting on the east side of a creek bed, you can use the downhill thermal pattern to your advantage by approaching a feeding area or water source located downhill from your position.

low-lying area thermals can help with selecting the best hunting spot

Urban Area Thermals

In urban areas, thermals can be heavily influenced by the heat generated by buildings, concrete surfaces, large paved blacktop areas, and traffic. Wind direction can also play a significant role in thermal patterns in urban areas.

When hunting in urban areas, it’s important to scout the area ahead of time and identify areas where thermals are likely to be influenced by the surrounding structures. Pay attention to the time of day and how it impacts the movement of air.

For example, during the morning, cool air tends to settle in low-lying areas and can be influenced by surrounding buildings, creating pockets of cooler air. In the evening, as the ground cools, the air tends to rise but can be influenced by surrounding buildings and concrete surfaces.

Hunting Morning Thermals

In the morning, deer will typically be feeding in low-lying areas and gradually make their way up to bedding areas as the day goes on. As a bow hunter, you can use the thermals to your advantage in the morning by setting up in a spot where the wind is blowing your scent away from the deer as they move up the hill. This will require you to get in early and be patient, as you’ll need to wait for the thermals to start rising before the deer start moving. Thermals are generally at their highest level between 9-10:00 a.m. each day.

In hill country, the cooler air tends to settle in the valleys while warmer air rises up the hillsides, creating an uphill thermal pattern in the morning. This means that thermals will be rising from the low-lying areas and traveling upslope. As a bow hunter, you can use the uphill thermal pattern to your advantage by approaching a deer bedding area located uphill from your position. This will allow you to remain undetected by the game you are hunting.

In low-lying areas, cool air tends to settle in the valleys during the morning, creating a downhill thermal pattern. This means that thermals will be descending from higher ground and traveling downslope. As a bow hunter, you can use the downhill thermal pattern to your advantage by approaching a feeding area or water source located downhill from your position. This will allow you to remain undetected by the game you are hunting.

In urban areas, thermals can be influenced by the heat generated by buildings, concrete surfaces, and traffic. During the morning, cool air tends to settle in low-lying areas and can be influenced by surrounding buildings, creating pockets of cooler air. Pay attention to the direction of the wind and how it is being influenced by the surrounding terrain.

What happens when winds and thermals collide and create alternate wind currents.
When winds and thermals collide, alternate wind directions and currents are created.

Hunting Mid-Day Thermals

During midday, thermals tend to be less predictable, but they typically rise as the sun heats up the ground. If you’re hunting near a bedding area, you’ll want to make sure you’re set up above the deer so that your scent is carried away from them as the thermals rise. If you’re hunting in a feeding area, you’ll want to be set up downwind of the deer so that your scent is carried away from them by the thermals.

As the day progresses, the sun’s energy warms the ground and causes the air to rise. In hill country, the uphill thermal pattern will become weaker, and the wind may shift direction. This means that thermals will be more inconsistent and may shift directions frequently. It’s important to remain patient and observant during mid-day hunting as the wind and thermals can change quickly.

In low-lying areas, as the day progresses, the downhill thermal pattern will become weaker and may shift directions frequently. Look for areas where there is a change in elevation, such as creek beds, gullies, and ditches, which can create natural funneling points for thermals. Pay attention to the direction of the wind and how it is being influenced by the surrounding terrain.

In urban areas, as the day progresses, the heat generated by buildings and concrete surfaces can create updrafts that rise and create thermals. Pay attention to the direction of the wind and how it is being influenced by the surrounding buildings and structures.

Hunting Evening Thermals

In the evening, the thermals will start to shift again as the ground cools down. Deer will typically start moving toward feeding areas as the sun begins to set. If you’re hunting in a feeding area, you’ll want to be set up downwind of the deer so that your scent is carried away from them by the thermals.

If you’re hunting near a bedding area, you’ll want to make sure you’re set up above the deer so that your scent is carried away from them as the thermals shift. These are key points to aid in understanding thermals when hunting deer, especially mature bucks. Evening thermals are at their strongest from approximately 4-5:00 p.m. each day.

In hill country, as the sun begins to set, the cooler air will start to sink down the hillsides and into the valleys, creating a downhill thermal pattern. This means that thermals will be descending from higher ground and traveling downslope. As a bow hunter, you can use the downhill thermal pattern to your advantage by approaching a feeding area or water source located downhill from your position.

In low-lying areas, as the sun begins to set, the air starts to rise from the valleys, creating an uphill thermal pattern. This means that thermals will be rising from the low-lying areas and traveling upslope. As a bow hunter, you can use the uphill thermal pattern to your advantage by approaching a bedding area located uphill from your position.

In urban areas, as the sun begins to set, the heat generated by buildings and concrete surfaces will start to dissipate, and the thermals will become more consistent. Pay attention to the direction of the wind and how it is being influenced by the surrounding buildings and structures.

Conclusion

By understanding the different thermal patterns in different types of terrain at different times of day, hunters can better predict the movement of the deer they are hunting and position themselves in the best location to take a shot. Remember to remain patient and observant, as the wind and thermals can change quickly, especially during mid-day hunting.

Ultimately, understanding thermals for deer hunting is all about paying attention to the details and being aware of how the wind and air currents are moving. By using the thermals to your advantage, you can increase your chances of success and avoid getting winded by the deer you’re hunting.

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