Groundwind
Southern Kentucky
See where your scent goes.
The cone rides the wind at head height, from the ground or 13 and 20 ft up a tree.
How it's drawn ›The first rule of hunting
Don't get winded.
Groundwind: the wind, thermals & scent app for deer, elk and moose.
We show you what the wind and thermals are doing at head height, exactly where your scent leaves you.
- Free in the beta
- iPhone and Android
- Works with no signal
Already carry onX or Windy? See what to keep them for.
It's made for your phone. Point the camera here to open it there, then add it to your home screen.
Dusk air drains your scent down the hollowPickle Lake, Ontario
The wind round the corner, and your scent
Lac Bailey, Québec
Set up the whole party.
Place every sitter and caller, and see whose scent drifts over whom before the evening sit.
Where the caller goes ›Northern Michigan
Tune the wind with a puff.
Puff your powder, tap where it went, and the map learns your spot.
How checks work ›
Why the wind at your face isn't the forecast.
Forecasts are calibrated 10 m in the air, over open ground. Your scent doesn't travel in a straight line. It bends over ridges, slows in the spruce, and drains downhill at dusk. Groundwind shows you where your scent is really going.
Go deep
The wind comes back behind the summit
- Behind the summitWhile the forecast shows a straight south wind over the mountain, Groundwind shows how it breaks off the summit, circles back, and pushes your scent up the north face.
- Cold air drainingOnce the sun goes down, air on a slope cools and slides downhill—regardless of what the forecast says. Groundwind maps your thermals.
- Up a treeFrom a deer stand, your scent rides the air before dropping. Hold your dot to tell the app you are 4 m or 6 m up, and the cone shows where your scent comes back down.
Forecast east, scent drains down the hollow
From the ground, then 13 and 20 ft up
So we built the wind for your ground.
Groundwind takes the 2.5 km HD forecast and solves it over HD LiDAR and every stand of trees, then adds the thermals, the leaves and the swirl, down to head height for any minute of the week. The cone is drawn where your scent is really going, from the ground or from your stand.
Every layer is built on published research, and it all runs on your phone with no bars.
The lake breeze, as the app drew it
- ForecastThe 2.5 km HD forecast (HRDPS) at 10 and 80 m, so it knows when the ground air comes loose from the wind above on a clear, cold night.
- TerrainA full 3D flow solve over the 1 m LiDAR ground, in 16 directions: faster over the bluff, slack in its lee, breaking off behind a summit and circling back. A new spot starts on our own wind model, trained on those solves across Canada and the US.
- Heat and coldCold air draining downhill at dusk, warm air rising upslope by day, lake and land breezes.
- Trees and leavesStand height and closure from the LiDAR point cloud, the hardwoods' leaves coming down by date, wind channelled down the slots between stands.
- Gusts and swirlThe forecast's gusts widen the cone, and the air tumbles behind tree lines, in openings and in the lee of a ridge.
- Your checksEach puff corrects the model near you and teaches it how that kind of air behaves at your spot.
Know the bush before you're in it.
The thicket that takes an hour to cross is where he beds. The old burn is where he feeds. Groundwind uses LiDAR to read the brush at eye level so you can plan your walk and your sit from camp. The bush comes with HD.
Go deep
Where the walking gets hard
The Hunt view: relief, contours and Range
- Shooting lanes and sight linesThe Hunt view maps open lanes and thick cover, and Dig in shows exactly how far you'll be able to see and shoot in eight directions.
- Route planningThick bush is loud and slow. The map finds the easiest walk in, and routes that keep your scent off the best ground.
- BushThe Bush view colours the brush between 0.5 and 3 m, from open to thicket: open, light, thick or thicket from the LiDAR point cloud.
Eye-level cover isn't the canopy. Satellite maps only show treetops, but a closed canopy shades the ground out and leaves the timber floor open and quiet to walk through. A cut or an old burn does the opposite—filling in with thick waist-high suckers and saplings. Groundwind reads the brush right at eye level, cell by cell, so you know where you can stalk quietly and where you'll be fighting thickets. Where there's no LiDAR point cloud yet, it estimates the brush from each stand's age and makeup.
On the move
A lot of moose and elk hunting is moving. You angle in on a bull you've heard, still-hunt an edge or work round a bluff, and that's where a forecast is least use. Before you step round the corner, see what the air is doing there and how far you'll see.
- AngleLog his grunts with Game. The map draws his line and where he'd swing to get your wind, so you can angle in from the right side.
- WindThe streaks run at head height: over the bluff, down the draw, round the edge of the stand.
- ScentDrop a cone at the corner ahead and see where you'd blow before you get there.
- RangeBefore you step out, the shooting lanes and the sight lines tell you how far you'll see from the next spot.
A bluff, a corner and your scent
Routes and the log
Routes finds three ways in on foot over the LiDAR ground. One is the easiest walk, and the hunt routes skirt the best ground and keep your scent off it. Your track, the calls you heard and your wind checks are grouped into outings as you go.
Dial in the forecast.
Puff your powder and tap where it went. Groundwind learns your spot with every check. The more you put in, the fewer surprises at your stand.
Go deep
One check, and the cone follows.
- Right awayYou see where your scent is really going, so you know whether to stay or move.
- Through the sitPuff again when the light changes and you catch the evening switch as it happens.
- Next huntThe map starts closer to what you felt last time, so you plan the sit with more confidence.
- Set up your partyDrop sitters on the map and see whose scent drifts over whom, so you can put the caller 40 to 50 m upwind of the shooter. More on calling with the wind.
A check pulls the ground wind inside its ring toward what you felt, and it fades with time, more slowly if you say the wind has held. It also becomes a lesson for its kind of air, like cold air draining, a lake breeze or a slot in the trees. That lesson is a turn and a speed correction the model applies wherever that air turns up, forgotten over about two weeks. How many puffs it takes, and how long they hold.
Plan the evening: 1's scent drifts over 2
Each check saves what the forecast and the model said beside what you felt, so the hunt log keeps score of how often each was right. If you say yes when the app asks, your checks also come to us without your name or notes, and Groundwind gets to know your spot from them. Settings, then Share wind checks, switches it off.
When does game move? We keep score.
Groundwind scores movement for moose and deer across your area, hour by hour, based on habitat, the rut, canopy cover, and the last 10 days of weather.
Big game feels the heat early. By the third day of highs over 18 °C, moose bed through the heat and move at night. Groundwind flags the first cool day that breaks the heat wave.
Go deep
Where they'll be
Groundwind scores moose, deer, grouse and bear across your area, hour by hour for the week ahead, from the habitat, the last ten days of weather, the wind, the rut and the leaves. It doesn't mean they're there. Log what you see and the map leans toward it for about a week, and blank sits push it down. Every score shows its reasons, and every rule is a knob from off to double.
- MooseBrowse 5 to 20 years after a cut or burn, close to cover. Shores in the rut. Bedded through a warm spell, moving on the first cool day.
- DeerSouth-facing aspen and hazel near cuts, lakes and roads.
- GrouseYoung aspen over alder, or spruce and jack pine for spruce grouse. Tight in wind and rain, out on the roads at dawn and dusk.
- BearBerries in 6 to 20-year cuts and burns through September, then denning cover.
A warm week beds them down
Groundwind reads the last ten days of highs beside the forecast, because moose feel heat early. Every hour's score carries the temperature, and the scoring says plainly when the game is lying up and when the break is coming. The rules come from habitat guides and published field studies.
- Moose, deerHeat stress starts near 14 °C. By the third day of highs over 18 °C they bed through the heat and move at night. The first cool day after is the one to be out.
- GrouseTight in wind over 25 km/h and in rain. Calm, cool mornings and the two hours before dark.
- BearLess bothered by heat. On the berries through September, then into denning cover after mid-October.
As a table
| Temperature | Moose activity |
|---|---|
| 10 °C or under | Full |
| 10 to 14 °C | 80% |
| 14 to 20 °C | Half |
| Over 20 °C | About a third |
An example week, in the app's words
- Mon19°
- Tue21°
- Wed22°
- Thu13°
warm spell, day 3: bedded through the heat, moving at night
first cool day after 3 warm ones: expect movement
The heat shifts with the week's weather
Offline, off-grid, and satellite ready.
Save your area at camp and it all works with no bars. Out for days? One text from an inReach or a satellite iPhone brings back the next two days of HD forecast.
Go deep
- No signal requiredYour track, pins, and wind checks are all saved locally.
- inReach / satellite syncOut for days? Text Groundwind from your inReach or iPhone satellite, and the next 48 hours of HD weather data comes back in a single 160-character text message.
With signal, Groundwind asks for each new run of the 2.5 km HD forecast (HRDPS) as it lands, four times a day, and saves the next two days on your phone with a seven-day outlook behind them. Walk out of service and it's still there, with its age shown.
Out for days, send the line the app writes for your camp to the Groundwind number from an iPhone on satellite or an inReach. The next two days come back in one 160-character text. Paste it in and the ground wind, your scent cone and the heat map all run on it, because the terrain and the bush are already on your phone.
A single 160-character satellite text packs in 48 hours of wind shifts, gusts, temperatures, and rain. The first few words are plain English for an inReach or satellite iPhone screen: the current wind, the next big shift, and the first rain. The rest feeds straight into the app—updating your scent cones and terrain wind with zero cell service. Sign in once while you still have signal, and the number answers your texts. Two messages on your satellite plan, and you're set for two days.
Two days of HD forecast in one text
Prepare as much as you can, bring the best tools you can to the hunt, and adjust it while you're out there, because we all know the best plans don't survive contact with the real world.
We need your help.
Groundwind gets better with every check you put in. Share your wind checks when the app asks and it gets to know your spot, so we can all be more successful on our hunts. They go without your name or notes, and other hunters never see them.
Try it on our spots.
- Pickle LakeNear White River, ON · WMU 21B
- Lac BaileyQuébec · zone 18
- ClearwaterAlberta · WMU 326
- Blanchard RiverBC · MU 6-28
- Pigeon RiverMichigan · DMU 069
Tap one to open it in the app. Yours will look just like these once it's built.
Put it on your phone, step by step: iPhone or Android, under a minute.
Got it.
Not in your inbox? Look in Junk or Spam: some mail services put a first email from us there.
Questions
What is Groundwind?
Groundwind is a hunting app that shows the wind at head height and where your scent goes, for moose, elk, deer and bear. It takes the 2.5 km HD forecast (HRDPS), solves it over the 1 m LiDAR ground and every stand of trees, adds the thermals, and draws your scent cone from where you sit. Your own wind checks correct it, and it all works on your phone with no signal.
What does it cost?
Nothing. Groundwind is free during the beta, and you can ask for up to three spots a day.
iPhone or Android?
Both. Groundwind runs in your phone's browser and goes on the home screen like any app: on an iPhone, Safari's Share, then View More, then Add to Home Screen; on Android, Chrome's Install app. No app store and no account.
Does it work with no service?
Yes, once your area is saved on the phone (Settings, then Maps on this phone). The forecast you saved at camp keeps working with its age shown, and your track, calls and wind checks are kept as you go. Out for days, text for the newest forecast from an iPhone on satellite or an inReach: ⋯, then Weather by satellite.
Where does it work?
Our spots open on every phone: Pickle Lake in Ontario, Lac Bailey in Québec, Clearwater in Alberta, the Blanchard River in BC and Pigeon River in Michigan. For your own, tell us where you hunt, and we build it and email you when it's ready. HD, built on 1 m LiDAR and the forest inventory, is made to order around your spot.
Why not everywhere?
We build spots anywhere in the US and Canada. Tell us where you hunt and yours is ready in 1 to 2 hours; we email you when it is.
How is it different from onX, HuntWise or Windy?
onX and iHunter cover every province and state, and Windy covers the weather for the whole continent. Groundwind goes deep on the ground you hunt, and out there it's your hunt partner, there to help you make better decisions when it counts. HuntWise, HuntStand and Windy show a forecast wind, worked out for 10 m up over open ground. Groundwind takes it down to head height over your ridge, your stands of trees and your shoreline, draws your scent on that, and lets a puff of powder correct it. Carry it beside them for the last hundred metres. It draws property lines on any spot in Canada and the US, and leaves owners' names to onX and iHunter. What each app does, side by side. Already have your stands in onX? Bring them over, and the file is read on your phone.
What's the best moose hunting app?
For the hunt itself, Groundwind: the wind at head height, your scent cone, where a called bull will swing for your wind, and the whole party's scent on every phone, with no signal needed. For hunting zones and regulations across the province, carry iHunter or onX Hunt beside it. What each app is for in a moose hunt.
Does it show property lines?
Yes, on any spot in Canada or the US. In Ontario, BC, the Yukon and Alberta it draws the lot lines and shows which land is private, as far as each province's open data says. Across Canada it marks First Nation reserves, parks and protected areas, and in Québec the ZECs, outfitters' territories and wildlife reserves. In the US it marks public, closed and tribal land and shows the rest as likely private. It never shows owners' names, and the lines are approximate, so ask before you cross.
What's a scent cone?
A scent cone is the patch downwind of you where an animal can smell you. Drawn from the forecast, it points straight downwind. Groundwind draws it on the wind at head height, so it bends round the ridge, drains downhill at dusk and widens in the gusts and in the lee of a tree line. Hold your dot to say whether you sit on the ground or in a 4 or 6 m stand, and the cone comes down where your scent would.
What happens to my data?
Your tracks never leave your phone. What comes to us is usage stats: which buttons and screens get used and for how long, under a random id for the phone, so we know what to make better. For a spot you load, its rough area, to about 10 km, so we know where to build next, and whether you're out on it, yes or no, so we know it's used in the field. Never your position, your pins or anything you type, and Settings, then Usage stats switches it off. Your wind checks come only if you say yes when the app asks, after your first one: where and when each was made, what you felt and what the map said, without your name or notes. They teach the wind map how the air moves where you hunt, other hunters never see them, and Settings, then Share wind checks switches it off. Sign in, and your spots, pins, hunt log and wind checks are kept on your account, so they're on every phone you sign in on. Anything else comes only if you send it: a spot you share, or a log you upload when something's wrong. The one exception: if the app crashes, the next time it opens it sends us a short record of what it was doing just before, with your position rounded to about 10 km and the names you gave things taken out, so we can fix it. Usage stats off stops that too. The forecast is fetched from Open-Meteo for your area. The privacy policy has all of it.
This site counts its visits the same way: which parts of a page come on screen and for how long, what gets tapped and where a visit came from, under a random id for your browser. For a spot you look up, its rough area, to about 10 km, or the words if the search finds nothing, so it learns them; never anything else you type. A browser with Global Privacy Control on sends nothing. During the beta, when you ask for a spot or sign in, we keep your visits and your use of the app with your email, so we can see what helped and what got in the way.
How right is the ground wind?
It's a model, and every model is wrong somewhere. That's why the checks exist: a puff of powder at your spot beats any forecast, and the hunt log keeps score of how often the forecast and the model matched what you felt.
Does it get better the more I use it?
Yes. Every wind check shows where your scent is going right then, and makes the map more accurate on your ground the next time. Check when you settle in, and again when the thermals switch at dawn or dusk. That's when the air is hardest to read.
Can't I just use a bottle of wind powder and save my battery?
Carry both. Powder tells you what the air is doing two feet from your face right now. It won't tell you that 50 yards down the draw, your scent makes a sharp left turn into the cedar swamp where the buck is bedded. A puff of powder tunes Groundwind to the exact air at your spot; the app shows where that air travels next.
What if my hunting partner doesn't believe the map?
Put him 40 yards downwind on the map's scent cone. When the bull winds him and barks at 60 yards, ask him how his scent-suit is holding up.
Does Groundwind guarantee I'll tag out?
No. If we could guarantee a bull, we'd charge $10,000 and guide you ourselves. Groundwind keeps you from blowing him out of the county with your scent before you even see him. After that, your aim and your patience are on you.
Field notes
How far can a deer smell you?
There's no one distance. What's measured about the nose, what the wind does with your scent, and pee, smoke and bug spray.
Read ›Does scent control work?
What's been tested on carbon clothing, sprays and ozone, and what cutting your scent does to the cone.
Read ›Rut wind
Bucks come in downwind. Creek bottoms, thermal hubs and windy days, and when the rut peaks where you hunt.
Read ›Treestands and scent
Where your scent comes back down from 13 and 20 ft up, by day, at night and under the trees.
Read ›Hunting thermals
Thermals switch when the sun reaches your slope. Where your scent goes at dawn and dusk, and where to sit.
Read ›How far can a deer smell you?
There's no one distance. What's measured about the nose, what the wind does with your scent, and pee, smoke and bug spray.
Read ›Calling moose with the wind
Why the bull circles for your wind, and where the caller and the shooter go.
Read ›Wind checks
How many puffs of powder tune the wind to your spot, where to take them and how long they hold.
Read ›