Winter predator hunting puts you on ground that looks, to a thermal sensor, almost nothing like the ground you hunted in October. A fence line under four inches of fresh snow at two in the morning is a large, cold, even surface with almost no texture in it. That is the best background a thermal channel will ever be handed, and it changes one practical thing: which palette you leave the scope in while you scan. The ATN ThOR 6 640x512 | 2-16x carries six — White Hot, Black Hot, Iron Red, Alarm, Green Hot and Sepia — and on snow only two of them are worth arguing about.
What snow does to a thermal picture
Snow gives you an unusually cold and unusually uniform background, and a thermal optic reads nothing but the difference between the target and that background. A coyote's coat sits well above a snowfield in temperature, so the signature separates hard. The flatness matters as much as the cold: bare frozen ground still holds rocks, stubble and drainage that each sit at their own temperature and clutter the frame, while an even blanket of snow removes most of that noise. ATN's own guidance is that cooler nights are the best conditions for thermal and that heat and humidity are the worst, and a snowed-in field is the far end of the good side.
How to pick a palette, step by step
Work it in this order and you will stop fiddling with the menu mid-stand.
- Set the palette before you set up, not after the call. On the ThOR 6 the palette cycles from the menu; on the handheld monoculars it is a press of the centre button. Either way you do not want to be hunting for it with a dog already committed.
- Scan in whichever palette makes a moving heat source obvious to your eye. Detection is a pattern-recognition job, and the palette that makes your eye jump is the right one for you.
- Switch to confirm. When something is standing in the open at 200 yards and you need to sort coyote from farm dog, changing palette gives you a second read on the same signature without moving the rifle.
- Trim brightness and contrast, not the palette. The ThOR 6 image settings carry brightness, contrast and edge sharpness. On a bright snow background those are the controls that fix a washed-looking frame.
- Leave Hot Point Tracking on while you scan. It flags the hottest object in the field of view, which on an even snowfield is almost always the thing you are looking for.
What each palette actually does
These are ATN's own definitions from the manuals, not field folklore. Read them literally — each one only tells you how temperature maps to colour.
- White Hot. Objects with high temperature are white; the higher the temperature, the brighter the colour. On snow, the animal is the bright object and the field is dark.
- Black Hot. Objects with high temperature are black; the higher the temperature, the darker the colour. On snow, the animal is the dark object and the field is light.
- Iron Red. Objects with high temperature are red; the higher the temperature, the brighter the colour.
- Alarm. Objects with high temperature are red, so the objects stand out.
- Green Hot. Objects with high temperature are green; the higher the temperature, the darker the colour.
- Sepia. Objects with high temperature are brown; the higher the temperature, the darker the colour.
White Hot against Black Hot on snow
ATN publishes what each palette does, not which one wins a given night, so what follows is how I run mine. In White Hot a coyote on snow is a bright animal on a dark field, and that inversion of the real world is the part some people never get comfortable with. In Black Hot the same coyote is a dark animal on a light field, which looks like what your eye expects from a snowy night and is why I scan in it after a fresh fall. Both work. The one that matters is the one you can read in the second and a half you get when a dog crosses a gap. Try both on the same stand before you decide, because that preference is personal and it does not transfer from one hunter to another.
What to check before a winter sit
Palette is the last thing on the list, not the first. Check the optic is inside its published band — the ThOR 6 640 2-16x is rated -30°C to 55°C (-22°F to 131°F) and IP67. Charge indoors, because ATN's manuals call for keeping the battery between 32°F and 140°F while charging, and carry the replaceable 18650 somewhere warm. Set your reticle style and transparency at the truck; the ThOR 6 has ten reticle styles and a transparency control, and a thin reticle over a bright snow background is easier to lose than you think. Then pick a palette and leave it alone. If the cold side of the equipment question is what you are chasing, our engineering page on cold-weather thermal performance below freezing handles the ratings in detail.
Common mistakes on snow
The first is cranking brightness to fight a snow field that is already bright. It flattens the exact difference you are trying to see; back the brightness off and lift contrast instead. The second is cycling palettes while a dog is working — every second in a menu is a second not on the animal. The third is treating digital zoom as detail: the ThOR 6 gives 1×, 2×, 4× and 8×, and on a distant signature that only makes a small blob a large blob. Scan at low magnification and zoom only to confirm. The fourth is forgetting the objective. Blowing snow and melt-water on the lens will cost you more picture than any palette choice ever will.
The ATN ThOR 6 640x512 | 2-16x on a winter stand
For predator work in snow the 2-16x is the version I would mount. It runs a 640×512 12µm VOx uncooled array at 50 Hz with ≤15mK NETD behind a 35 mm germanium objective at F/1.0, giving 12.52° × 9.41° of field of view and 3100 m of rated detection range. That field of view is the reason it beats the 50 mm version on called stands: the 3-24x reaches 3650 m but shows you only 8.78° × 6.59°, and a coyote circling downwind moves across your frame faster than you can follow it through a narrow one. The body is magnesium alloy, IP67, 830 g / 1.83 lbs, rated to 6000 Joules and to -30°C to 55°C. Add Zeroing Freeze, Picture-in-Picture, Hot Point Tracking, Recoil Activated Video and about nine hours on one internal and one replaceable 18650.
Is palette choice worth fussing over?
It is worth ten minutes once, and then never again. Palettes do not change what the sensor detects — a ≤15mK detector resolves the same temperature difference whichever colour map is on the display. What they change is how fast your eye finds it, and on a called stand the difference between spotting a dog at 250 yards and at 120 yards is the whole hunt. Settle your preference on a quiet night with no caller running, then stop thinking about it.
Winter thermal palettes: common questions
What is the best thermal palette for hunting in snow?
There is no published "best" — ATN specifies what each palette does, not which suits a condition. White Hot shows a coyote bright on a dark field; Black Hot shows it dark on a light one. Test both on the same stand and keep whichever your eye reads faster.
How many colour palettes does the ATN ThOR 6 have?
Six: White Hot, Black Hot, Iron Red, Alarm, Green Hot and Sepia. The same six are listed on the ThOR 6 640x512 2-16x and 3-24x, the THOR-6 384×288 2.5-20x, the ThOR 6 Mini 256×192 2-16x and the BlazeTrek 6 640 monocular.
Does snow reduce thermal detection range?
Falling snow does not blind a thermal channel, and cold, even ground generally makes a warm animal easier to pick out. Published detection ranges such as the 3100 m on the ThOR 6 640 2-16x are single rated figures, not weather-adjusted ones.
Can I tell a coyote from a dog through a thermal scope?
At sensible distance, yes — gait and body line give it away before coat detail does. That is a resolution question more than a palette one, which is why the 640×512 sensor earns its price on open winter ground.
Should I change palette to shoot, or only to scan?
Scan in the palette your eye reads fastest and switch only to confirm a questionable target. Changing palettes with an animal committed costs you time you do not have, and the reticle stays in the same place either way.
Does cold weather shorten the battery on a winter stand?
It can. ATN states that battery life is unaffected in most conditions and that extreme cold may reduce battery performance, without publishing a figure. Carry the replaceable 18650 in an inside pocket and treat the rated nine hours as a warm-weather number.
The short version
Snow is a gift to a thermal channel: cold, flat and quiet. Learn what the six palettes actually do, pick the one your eye reads fastest, fix the picture with contrast rather than brightness, and spend the rest of your attention on the wind and the approach. For the calling side — positioning, sound sequence, distances and which optic goes in which hand — that is all laid out in our late-fall coyote calling setup, and if you are still choosing the optic itself, start with our ranking of the best thermal scope for coyote hunting or the current line of ATN thermal scopes.
Quick spec reference
- Featured optic: ATN ThOR 6 640x512 | 2-16x, SKU TIWST6635A
- Palettes: White Hot, Black Hot, Iron Red, Alarm, Green Hot, Sepia (six)
- Sensor and optics: 640×512, 12µm VOx uncooled, 50 Hz, ≤15mK NETD; 35 mm (Ge) F/1.0; 12.52° × 9.41°; 3100 m detection
- Narrower, longer sibling: THOR-6 640×512 3-24x (TIWST6650A) — 50 mm (Ge), 8.78° × 6.59°, 3650 m
- Winter-relevant build: magnesium alloy, IP67, -30°C to 55°C, 830 g / 1.83 lbs, ~9 hrs on 18650 cells
