Gasoline stays fluid near −60 °C; diesel waxes around −9 to −19 °C and can gel below −34 °C; Jet A-1 freezes at or below −47 °C.
Two ideas sit behind every cold-weather chart: the temperature where crystals first appear, and the point where a liquid no longer moves. Engineers give those points names. Drivers and pilots feel them as rough starts, clogged filters, or a tank that won’t feed. Let’s map the numbers and the why.
Fuel freeze or gel thresholds at a glance
Use this quick table as a starting point. Values are typical, not hard limits. Blends, additives, and specs change the picture. The notes show what “freezing” means for each fuel in practice.
| Fuel | What “freezing” means | Typical threshold |
|---|---|---|
| Gasoline (petrol) | Loss of volatility; true solid only at extreme cold | Thickening below about −40 °C to −60 °C; rare full solid near −73 °C or lower |
| Diesel No.2 (ULSD) | Wax crystals form, then filters plug, then no flow | Cloud point ~ −9 °C to −19 °C; gel/pour often below −34 °C without additives |
| Biodiesel (B100) | Fat-based esters solidify early | Cloud point commonly −3 °C to +15 °C, feedstock-dependent |
| Renewable diesel (HVO) | Paraffins tuned by isomerization; wide range | Cloud point varies widely by producer; winter grades can be well below −20 °C |
| Jet A | Spec freeze point | ≤ −40 °C by specification |
| Jet A-1 | Spec freeze point | ≤ −47 °C by specification |
| Propane (LPG) | True melting of pure propane under pressure | Melting near −188 °C; far below any ambient on Earth |
Why “freezing” means different things
Water flips from liquid to ice at a set point. Hydrocarbon fuels don’t behave that way. They are blends of many molecules, each with its own behavior. As temperature drops, heavier parts fall out first. That’s why diesel grows cloudy, then slushy, then stops.
Three markers matter. Cloud point is when wax crystals first show up. Cold filter plugging point (CFPP) is where filters load up and flow through the element stops. Pour point is a lab check for “no movement.” In aviation, the spec calls out a freeze point where the last crystals disappear on warming. That keeps fuel lines, screens, and pumps safe at cruise.
These markers are set by test methods. Diesel cold-flow limits use ASTM procedures like D97 for pour point and D2500 for cloud point. Aviation fuels use D2386, D5901, or D7153 to read a freeze point. You’ll see those codes on supplier sheets and airport fuel certificates.
At what temperature does gasoline freeze?
Gasoline is a light blend aimed at easy vaporization. That’s why summer and winter grades differ. The mix rarely forms a hard solid in weather that humans experience. In lab work and field lore, thickening shows up below roughly −40 °C. Many blends keep flowing down near −50 °C or even lower. Reports of full solid tend to sit near −73 °C or beyond, well outside road conditions.
Engines still stumble sooner. Cold cranking needs vapor, not just liquid flow. Low volatility, heavy ends, and any dissolved water make starts rough long before any true freeze. Ethanol blends change the curve too. E10 behaves like gasoline; high-ethanol fuels lean on different rules that suit flex-fuel hardware.
Practical takeaways: buy season-appropriate gasoline, keep water out of tanks, seal caps tightly, and avoid long storage in the cold. If a car sits outside in arctic air, a block heater and a fresh battery help more than any bottle on a parts-store shelf.
At what temperature can diesel fuel gel?
Diesel carries long-chain paraffins. Those waxes bring good energy and smooth combustion, but they crystallize as temperature falls. The first hint is cloud point. That’s the “snow globe” moment when crystals appear. Filters catch them and flow drops. A few degrees lower and the fuel won’t pour in the lab.
Numbers depend on the grade. Summer No.2 ULSD often has a cloud point around −9 °C to −12 °C. A winter grade or a kerosene blend pushes that down toward −19 °C or lower. Additive packages help by changing crystal shape. Without help, lab pour points often land below −34 °C. Fleet managers watch CFPP, since that predicts the filter limit in service.
Good practice keeps machines running. Buy winterized diesel when nights turn cold. Treat on-site tanks ahead of the first cold snap. Drain water separators. Keep equipment parked with tanks near full to cut condensation. If a system plugs, move the unit inside and warm the filters; don’t torch the tank.
For deeper background on cloud, CFPP, and pour, see the Chevron diesel cold-flow review. It explains how a few degrees below cloud point can stop flow through a filter.
At what temperature do jet fuels freeze?
Jet fuels carry firm spec limits. Jet A must meet a freeze point of ≤ −40 °C. Jet A-1 must meet ≤ −47 °C. Those numbers give margin for long, high-altitude legs where tank temperatures can drop fast. Crews track fuel temp and flight planners choose routes and levels that keep a buffer above the spec.
Freeze point is measured with dedicated methods, then printed on batch tickets. Airport storage and delivery maintain traceability back to the refinery or terminal. For a clear spec summary, see Shell’s grade sheet for civil jet fuels and the Jet A versus Jet A-1 freeze limits there.
You can read a supplier view here: Shell civil jet fuel grades. Many product data sheets echo the same limits. A U.S. government handbook defines freeze point in plain terms for field work and training.
Ethanol blends, biodiesel, and renewable diesel
Ethanol itself has a low melting point (−114 °C), yet high-ethanol blends behave differently in engines because vaporization and water handling set the limits. E10 is common in road gasoline and starts like regular petrol. E85 is seasonal and flex-fuel systems calibrate for it. The DOE Alternative Fuels Data Center explains how blend ranges shift across regions.
Biodiesel (B100) is a different story. It’s made from fats and oils. Saturated esters raise cloud and pour points sharply. Depending on feedstock, B100 may show a cloud point anywhere from about −3 °C up to +15 °C or higher. Blends like B20 track closer to diesel but still need winter plans. Heated storage, insulated lines, and the right additive package make the difference.
Renewable diesel (HVO) doesn’t carry oxygen like biodiesel and can be tuned. Isomerization steps bend paraffin chains and lower cloud point. That’s why one HVO can fit deep-winter service while another behaves like a mild No.2. Suppliers publish cloud and CFPP by lot; read those sheets before you plan a blend.
Cold-flow markers you’ll see on data sheets
Specs and tickets use a few recurring markers. Here’s a short guide to the numbers and how to read them in the field.
| Marker | What it tells you | Typical values |
|---|---|---|
| Cloud point | Wax first visible; filters may start to load | Diesel No.2: ~ −9 °C to −19 °C; B100: −3 °C to +15 °C+ |
| CFPP | Cold filter plugging point; operability limit in many fleets | Varies by grade and additive; often ~ 2–10 °C below cloud |
| Pour point | Lab “no flow” check | Frequently 3–5 °C below cloud for untreated diesel |
| Freeze point | Aviation spec; last crystal disappears on warming | Jet A: ≤ −40 °C; Jet A-1: ≤ −47 °C |
Cold-weather tips that actually help
Pick the right grade before the first cold snap
Buy winter diesel when daytime highs start to slide. Upstream blending and additives do far more than a late bottle in a half-full tank. Ask your supplier for cloud point and CFPP targets.
Keep water out, then purge what gets in
Water turns to ice and grabs wax. Drain separators on trucks and heavy equipment. Inspect caps and vents. For storage tanks, stick water bottoms and clean on a schedule.
Protect the filter train
Use the correct micron rating and change elements ahead of winter. A plugged filter mimics a dead pump. Carry spares and a way to warm housings safely.
Park smart
Face equipment away from the wind. Use block heaters and fuel warmers where fitted. In deep cold, bring filters and small engines indoors overnight.
Read the paperwork
Fuel tickets, batch sheets, and supplier bulletins list cloud, CFPP, pour, and (for jet) freeze point. Those numbers beat rumor. For biodiesel specifics, the DOE biodiesel handling guide shows safe storage and cold-flow practices.
Testing, storage, and when to suspect the fuel
Engines that quit in the cold don’t always point to the pump. Wax and ice build upstream. Sample at the tank and the filter inlet; look for haze or flakes. Warm a sample and watch the crystals melt. If the fuel clears in a few minutes near room temperature, you likely hit the cold-flow limit.
On bulk sites, track deliveries against weather. Note cloud and CFPP on every load. Keep a log of filter changes. If one tank feeds many units, install a side-stream filter and a water drain you can service without taking gear offline.
For flight ops and airport maintenance, rely on certified lab results and spec sheets. Freeze point sits on every aviation batch ticket. Crew procedures require a buffer between measured freeze point and the lowest in-flight fuel temperature for the day’s route.
For a field definition of freeze point and other terms, see the training guide used across U.S. Interior aviation programs. It sets the wording used on many checklists.
Altitude, speed, and why jet fuel gets so cold
Airliners cruise in thin, frigid air. Skin temperatures can sit far below outside air because of airflow and radiation to the night sky. Fuel lives inside the wing, where that chill soaks in during long legs. Modern aircraft track tank temperature on the flight deck. If the trend creeps toward the spec limit, crews descend into warmer air or pick a faster level to slow the cooling. Dispatch tools predict those legs ahead of time, using route, winds, and cruise speed.
LPG, LNG, and CNG in the cold
Propane in bottles does not “freeze” during normal use. The melting point of pure propane sits near −188 °C. What users feel is loss of vapor as the liquid cools toward its boiling point (about −42 °C at atmospheric pressure). As cylinder pressure falls, burners starve. Warming the bottle in a safe way restores vapor.
LNG is another case. Methane melts near −182 °C, while storage happens around −162 °C. CNG carries gas in high-pressure tanks and does not form a solid in service. Ice from moisture in lines can still cause trouble, so dryers and quality checks matter for fleets.
Myths that keep coming back
- “Gasoline turns to jelly at a small minus number.” Starting gets hard long before any solid appears.
- “Additive fixes any diesel at the pump.” Additive needs time, mixing, and the right chemistry. Buying the right seasonal grade beats a late pour-in.
- “Jet fuel freeze point is just a suggestion.” It’s a hard spec with certified tests. Flight plans build a margin above it and crews watch the trend.
- “Propane stoves stop because the propane froze.” Loss of vapor, not a block of propane.
Numbers to remember
Gasoline keeps flowing to the sort of cold that few drivers face. Diesel needs winter prep because wax appears near the freezing point of water and grows fast from there. Jet fuel carries hard spec limits at −40 °C and −47 °C. Read tickets, match grades to weather, and treat storage as part of the machine. Match the grade to your climate each winter season.