How hot can a bitcoin miner run? The temperature rating, and why hot countries still work

Every miner's spec sheet carries a temperature range, and it is the one number on it that is about your site rather than the machine. Air-cooled machines are rated for intake air up to 35 to 45 °C depending on the maker; hydro machines are rated on the water, not the room. Here is how to read it, what happens when a room passes it, and why the hottest countries host some of the best sites.

Short answer: an air-cooled miner is rated for the air going in, usually up to 35 or 40 °C, and some to 45

A bitcoin miner turns almost every watt it draws into heat, and an air-cooled one gets rid of that heat by pulling room air through its hashboards with two or four large fans. How well that works depends on how cool the air is when it goes in. So every maker rates its machines for a range of intake-air temperature, and the top of that range is the number that matters: it is the hottest air the machine is designed to run at full speed on.

The ranges differ by maker and by model. In our catalogue, Bitmain's current air-cooled Antminers, the S21 Pro and S21 XP among them, are recorded at -20 to 45 °C. MicroBT's own operation guide for its air-cooled Whatsminers gives 0 to 40 °C for the M61 in normal mode, 0 to 35 °C in high-performance mode, and -5 to 35 °C for the M60S++. Canaan's A15 Pro+ is recorded at -5 to 35 °C. The same guide sets the room's humidity at 20 to 80% and its dust at under 0.5 milligrams per cubic metre, which is a cleaner room than most garages.

Those are intake figures, measured where the air enters the machine. The air in a well-run hall is not the air outside it. A hall in a country where the afternoon reaches 45 °C can be feeding its machines air at 30, because the building is designed to do exactly that. The question to ask a host is not what the weather is, but what the intake air is in the hottest week of the year.

The number on the sheet is the temperature of the air entering the machine, not the weather outside the building.

What a machine does when the air gets too hot

A modern miner does not simply run until it breaks. It measures the temperature of its chips and of the air leaving each hashboard, and it protects itself in steps. MicroBT's guide describes the first step plainly: if the air at the outlet of a hashboard goes above 80 °C and the fans are already above 7,000 revolutions per minute, the machine runs its chips at a reduced frequency, and the hashrate drops below normal. The guide's advice is to keep the ambient air around the machine below 30 °C to avoid it.

That is the first thing heat costs you: hashrate, quietly. A machine in a hot room still shows as online, still hashes, and earns less than its spec sheet says, with the fans at full speed. The second step, if the chips keep climbing, is a protective shutdown, and then the machine earns nothing until it cools and restarts. Why a miner's hashrate reads lower than its spec sheet covers the other reasons the number can fall; heat is the one that follows the calendar.

The third cost is slower. Fans running at full speed all summer wear out sooner, and chips that spend their lives near their limit age faster than chips that do not. Neither is dramatic, both are real, and both are the reason the rating exists. Running a machine on 40 °C intake air when it is rated for 35 is not forbidden; it is simply a machine earning less and wearing more than the one next to it in a cooler room.

Hydro and immersion machines are rated on the water, not the room

Hydro-cooled machines have no fans. The heat leaves through water running across cold plates on the hashboards, and the maker rates them for the temperature of that water. The hydro Antminers in our catalogue, the S23 XP Hyd and the S23 Hyd 3U among them, are recorded at 20 to 50 °C, and the figure is the inlet coolant, not the air in the hall. Immersion machines sit in a tank of dielectric fluid and are rated the same way, on the fluid.

That changes what a hot climate means. The site's job is to keep the water inside the range, and water is far easier to cool than air: it carries heat out of the building through pipes to dry coolers outside, large fan-and-coil units that shed it to the atmosphere, sized so the loop stays in range on the hottest day of the year. That is why hydro sites are built in deserts. Air, hydro or immersion explains the three systems; for temperature, the short version is that water buys a wider margin and the site pays for it in plant.

It also changes who bears the risk. With an air machine, the room has to be cool enough; with a hydro machine, the loop has to be run properly. A hydro site that lets its coolant drift above the range will hurt every machine on the loop at once, so the plant behind a hydro site is worth asking about before the rate is.

A hydro machine's spec sheet says 20 to 50 °C, and it means the coolant.

A rating is a rating at the maker's test conditions

The number on the sheet was measured in a laboratory, and Canaan says so on its own release for the A15 series, where every figure is "based on laboratory results in a controlled environment" and the company does not guarantee the same results in the field. Heat is the biggest thing that takes something off a rating, and it is not the only one: MicroBT's guide puts the room's humidity at 20 to 80% and its dust at under 0.5 milligrams per cubic metre, and its warranty terms exclude damage from "humid environments, corrosive environments, high-temperature environments, dust particles" and unstable voltage.

The practical point for a buyer is simple. A host who can tell you the intake temperature in the hottest week, the humidity and the filtration of the room is a host who has read the same sheet you have. A host who answers with the weather forecast has not.

Why the hottest countries host some of the best sites

Our three sites are in Argentina, Nigeria and the United Arab Emirates, and two of them are hot for much of the year. That is not a contradiction of anything above; it is the reason the sites are built the way they are. The UAE site runs hydro and immersion machines, so the hall's air temperature is not what the machines see, and its dry coolers are sized for a desert afternoon. It also sits near the manufacturer's warranty centre, and it runs at 99.3% uptime on the figures we publish for it.

Argentina and Nigeria run air-cooled machines, and an air-cooled hall in a hot country is an engineering job: fan walls that move enormous volumes of air, intakes placed and shielded so that hot exhaust never finds its way back to them, and rows laid out for the airflow rather than for the floor plan. Argentina runs at 98.7% uptime on our published figures. Nigeria runs at 73.6%, and the reason it hosts machines at all is its power price, 3.9 cents a kilowatt-hour against about 6 at the other two, which is what uptime and a cheaper site trade against each other.

What a hot country cannot do is run an air-cooled machine on unconditioned air in the afternoon and expect the spec sheet. Nobody serious does. The sites that work in hot places are the ones that treat the intake temperature as a number to be engineered, and the machines that go to the hottest places are increasingly the hydro ones, because water does not care what the air is doing.

What to check before you choose a site, or a machine for it

Start with the rating on the machine you are buying, and read it as an intake figure. If it says 35 °C, as the A15 Pro+ and the M60S++ do, it wants a cooler room than a machine rated to 45, and a host should be able to tell you what its hall runs at in summer. If the honest answer is near the limit, the machine will earn a little less than its sheet in the hot months, and you would rather know that before it is racked than read it off the dashboard in January.

Then match the cooling to the place. An air machine belongs in a hall built for air; a hydro machine belongs where there is a loop and the plant to keep it in range. Buying a 35 °C air machine for a hot site with an unconditioned hall, or a hydro machine for a site with no loop, is the mistake the rating is there to prevent. Our guide to reading a spec sheet covers the other numbers; this is the one about the room.

Last, ask about filtration and humidity, because dust and damp are the slow killers that the temperature rating does not cover. MicroBT's warranty, like every maker's, excludes damage from hot, humid, corrosive or dusty environments, so a hall that fails those tests costs you twice: in hashrate now and in a warranty claim later.

What it means for a miner

The temperature rating is the one number on the sheet that your site has to meet rather than the machine. Air-cooled machines are rated on the air going in, 35 to 45 °C at the top depending on the maker; hydro and immersion machines are rated on the water, 20 to 50 °C, and the room matters much less. Pass the rating and the machine earns its spec sheet; miss it and it earns less, quietly, and wears faster.

That is why the question to put to any host is about intake air, not weather, and why a hot country with a well-built hall or a water loop is a perfectly good place to mine, while a cool country with a bad room is not. The machine does not know what country it is in. It knows what temperature the air or the water is when it arrives.

Sources and further reading

WhatsMiner Air Cooling Miner Operation Guide V2.1 — MicroBT, read 13 Nov 2026
Canaan Upgraded Avalon Miner A15 Series with Superior Performance — Canaan Inc., via PR Newswire, 7 Nov 2024
Our sites — Firsthand Bitcoin, 13 Nov 2026

Disclosure

Firsthand Bitcoin sells and hosts mining hardware, including this machine. No manufacturer, distributor or affiliate programme paid for or reviewed this page and we take no commission on the links above. Historical figures are computed from daily bitcoin price and network hashprice, each day valued at its own prices. Nothing here is investment advice.