A single snow gun typically makes on the order of 50 to 250 cubic metres of snow per hour when conditions are good — but output is not a fixed spec. It is set by how much water the gun can atomise and, above all, by the wet-bulb temperature. In marginal conditions the same gun can drop to a fraction of that, or make no usable snow at all.
"How much snow per hour" is the question every snowmaking manager and backyard snowmaker actually cares about, and the honest answer is a conversion, not a number. Output follows water throughput, water throughput follows the cold, and the cold is measured by wet-bulb temperature. This guide gives you the ranges, the conversion maths, and the reason the wet-bulb window — not the gun on the brochure — governs how fast you build a base.
Key takeaways
- Snow-gun output is driven by water flow, and water flow is throttled by wet-bulb temperature — not a fixed machine rating.
- A rough rule: 1 m³ of water yields about 2–2.5 m³ of machine snow (artificial snow density ~300–500 kg/m³).
- Fan guns move far more water than lances, so per-unit hourly output is higher; lances trade output for very low energy and simplicity.
- Output collapses near the margin: at a wet-bulb close to −2 °C a gun runs at a trickle; at −8 °C or colder it runs wide open.
- A wider effective wet-bulb window means more full-output hours per season — the lever behind season extension. SL6733's +3 °C figure is modelled and pre-commercial.
How much snow does a snow gun make per hour?
Under favourable conditions, a typical automated fan gun produces roughly 50–250 m³ of machine snow per hour, and a lance somewhat less, because output tracks the water the gun can atomise into freezing air. The exact figure depends on the model, the water pressure and flow available, and — decisively — the wet-bulb temperature at the nozzle. Treat any single "per hour" number as a best-case, not a constant.
Manufacturers publish output at a reference wet-bulb (often around −5 to −10 °C) and full water pressure. Those are ceiling figures. The number that matters operationally is this gun, on this night, at this wet-bulb, which is usually well below the brochure. This is why snowmaking is planned around cold windows rather than gun counts, a point developed in the wet-bulb temperature guide.
How do you convert water flow into snow volume?
Use the density of machine snow. One cubic metre of water weighs about 1,000 kg, and machine-made snow packs at roughly 300–500 kg/m³, so a cubic metre of water becomes about 2 to 2.5 m³ of snow. Multiply a gun's water flow rate by that factor to estimate hourly output, then discount for evaporation and overspray loss.
The chain of reasoning:
- Machine snow is dense — about 300–500 kg/m³ versus 30–100 kg/m³ for fresh natural snow. It is closer to a firm base than to powder by design.
- At ~400 kg/m³, 1,000 kg of water (1 m³) makes roughly 2.5 m³ of snow.
- So a gun flowing 10 litres per second — 36 m³ of water per hour — makes on the order of 70–90 m³ of snow per hour, before losses.
- Real yield is lower: some water leaves as vapour or drifts off-trail, more so as conditions warm.
The illustrative table below shows the conversion across representative flow rates. Flow figures are typical ranges, not manufacturer specifications, and assume good wet-bulb conditions:
| Device (illustrative) | Water flow | Water per hour | Approx. snow per hour | |---|---|---|---| | Snow lance | ~3–7 l/s | ~11–25 m³ | ~25–60 m³ | | Mid fan gun | ~7–15 l/s | ~25–54 m³ | ~55–130 m³ | | High-output fan gun | ~15–30 l/s | ~54–108 m³ | ~120–270 m³ |
The gun-type trade-off — output versus energy and cost — is the subject of snow gun versus snow lance.
Why does wet-bulb temperature govern output?
Because snow only forms when the tiny water droplets can shed their latent heat and freeze before they land — and how fast they can do that is set by the wet-bulb temperature, which combines air temperature and humidity. As the wet-bulb rises toward the freezing threshold, operators must cut water flow so each droplet gets enough cooling, and output falls with it.
Wet-bulb, not dry-bulb, is the controlling variable because evaporative cooling does much of the freezing work; drier air freezes droplets that warmer, wetter air would not. The operational consequences:
- At a cold wet-bulb (−8 °C and below): guns run at full water flow, and output is at or near the brochure figure.
- In the marginal window (around −2 to −5 °C): operators throttle water down to keep the snow dry, so hourly output drops sharply.
- Above roughly −2 °C wet-bulb: conventional snowmaking becomes inefficient or impossible, and output falls toward zero.
That collapse near the margin is why "how much snow per hour" is really a question about how many hours you can run at all. The strategies for the warm end are in making snow at warmer temperatures.
How many hours does it take to build a base?
Enough hours that the constraint is rarely the guns — it is the cold windows and the water permit. Covering one hectare to a 30 cm skiable base takes on the order of 3,000 m³ of snow, which a bank of high-output guns can lay down in a night or two of good cold, but only if the wet-bulb cooperates and the abstraction licence allows the draw.
Working the numbers with the conversion above: a hectare at 30 cm depth is roughly 3,000 m³ of snow, requiring about 1,200–1,500 m³ of water. A line of ten high-output fan guns at full flow moves enough water to make that in a couple of solid cold nights. Season-wide, snowmaking consumes roughly 2,900 m³ of water per hectare in Austria (Aigner, Steiger & Mayer 2026) across repeated resurfacing and top-ups — the water side of which is detailed in how much water snowmaking uses.
The binding constraints, in order, are usually:
- Available cold hours — the number of nights the wet-bulb sits low enough to run.
- Water throughput — pump-house capacity and abstraction-permit ceilings.
- Gun capacity — rarely the limiting factor at a modern resort.
How can a resort get more output from the same guns?
By widening the temperature window in which the guns can run at meaningful output, and by running them efficiently within it — not by buying bigger guns. Every additional hour of workable wet-bulb is an hour of production a resort would otherwise lose, and near the margin those hours are the scarcest resource in the operation.
The efficiency levers:
- Optimised timing and automation — chasing the coldest hours of each night and shutting down as the wet-bulb rises.
- Water and air conditioning — colder feed water and well-tuned nucleation lift output at a given wet-bulb.
- Additive chemistry — a chemistry-based lever that, in modelled operator scenarios, shifts the effective workable wet-bulb window by about +3 °C, converting previously unusable warm hours into productive ones and adding a modelled 300–500 snowmaking hours per season. These are pre-commercial figures, not resort-demonstrated results.
The third lever is the one most operators have not costed, because the chemistry sits outside the equipment conversation. Its whole value is measured in recovered hours — the season-extension logic set out in extending your ski season.
How much water is lost rather than turned into snow?
Some, and more of it as conditions warm — which is why nameplate output overstates real yield. Not every droplet that leaves the nozzle lands as snow: a fraction evaporates in flight, and another fraction drifts off the trail as fine mist, especially in wind or near the margin. The conversion factor of 2–2.5 m³ of snow per m³ of water is a good-conditions figure; discount it when the wet-bulb is high.
Where the water goes:
- Deposited as snow — the bulk of it, in good cold with low wind.
- Evaporative loss — droplets that fully sublimate or evaporate before landing; higher in dry, warm, or windy air.
- Overspray and drift — mist carried off the target trail, a larger share near the margin where flow is throttled and droplets are finer.
None of this water is destroyed — it returns to the catchment on melt — but it does not build base, so it is lost output. This matters twice over: it lowers effective m³-per-hour, and it means the abstraction permit works harder for each metre of coverage. Running in the coldest hours, out of the wind, is as much about yield as about snow quality — the wider quality story is in why machine snow comes out wet.
The bottom line
A snow gun's output is a conversion, not a constant: water flow times the snow-density factor, heavily discounted by the wet-bulb temperature. Expect tens to a couple of hundred cubic metres per hour from a single gun in good cold, far less near the margin, and roughly 2–2.5 m³ of snow per m³ of water. The real determinant of how fast you build a base is how many cold hours you get and how much water you may draw — which is exactly why widening the workable temperature window, rather than adding guns, is where the leverage is.
If you want to model how a wider marginal-temperature window changes your seasonal output and hours, request a pilot or send us a message.
Output and flow figures here are illustrative ranges for orientation, not manufacturer specifications — confirm any specific machine's rating with its maker. SL6733's +3 °C wet-bulb advantage and 300–500 added-hours figures are modelled and pre-commercial.