Cold weather turns routine fueling into a reliability test. This guide explains how winter diesel blends work, when to use #1 diesel, how anti-gel additives help, what CFPP and cloud point mean, and practical steps to keep fleets, tanks, and generators running all winter.

Why diesel "gels" in cold weather

As temperatures drop, wax crystals in diesel begin to form. Enough crystals can clog filters and starve engines. Water in tanks can also freeze and block flow. The fix is a combination of the right winter fuel blend, proper additives, and good tank housekeeping, none of which happens automatically once the first cold snap hits.

#1 vs. #2 diesel: what changes and when to blend

• #2 diesel (ULSD #2) is standard for most of the year, with higher energy content and better fuel economy.

• #1 diesel (kerosene/ULSD #1) has fewer waxes and flows better in cold weather, but slightly lower energy content.

Common winter approaches:

• Mild cold: stay with treated #2 plus anti-gel.

• Moderate cold: roughly 70/30 #2/#1, varying by market.

• Severe cold: 50/50 or higher #1 content, based on your operability targets.

Your exact ratio should match local temperatures, OEM guidance, and supplier recommendations. Blending is usually done at the terminal or by your supplier, not at the job site.

Anti-gel additives and how they help

Cold-flow improvers modify wax crystal formation so fuel keeps flowing through filters at lower temperatures. Many winter packages also include:

• De-icers to address dissolved water

• Detergents for injector cleanliness

• Cetane improvers for easier cold starts

Follow supplier treat rates; over-treating doesn't equal better performance.

CFPP, cloud point, and pour point explained

• Cloud Point: the temperature where wax crystals first appear; fuel looks hazy.

• CFPP (Cold Filter Plugging Point): the lowest temperature at which fuel will pass a standardized filter, a practical "will it run" indicator.

• Pour Point: the lowest temperature fuel still flows under gravity, typically lower than CFPP.

Target a CFPP comfortably below your lowest expected ambient temperature for the region you operate in.

Biodiesel and renewable diesel in winter

• Biodiesel blends (B5–B20) raise the cloud point versus straight ULSD. Many fleets reduce biodiesel percentage in winter or use enhanced additive packages instead.

• Renewable diesel (RD) often has excellent cold-flow properties and can be a strong winter option where available.

• Always confirm OEM and local spec requirements before changing blends mid-season.

Winter readiness checklist for sites and fleets

Tanks and equipment

• Remove water, drain separators, and keep caps and gaskets tight.

• Replace clogged filters proactively; stock winter-rated spares.

• Verify tank fill points are accessible in snow and ice.

• Confirm a winterized fuel or additive plan is in place before the first hard freeze.

Fleet and operations

• Standardize cold-weather startup procedures and idle limits.

• Bundle DEF with diesel deliveries; DEF freezes around 12°F/−11°C but can be re-liquefied without damage.

• Train teams on clear vs. dyed diesel rules for highway vs. off-road equipment.

Procurement

• Set regional #1/#2 ratios and additive specs with suppliers ahead of season.

• Stage emergency coverage and lead-time expectations for storms.

• Centralize invoices and drop tickets for audit and tax documentation.

How Fuel Me automates winter fueling

Winter readiness runs on the same five capabilities that power the rest of the platform, whether you're on Control (audit and visibility on your existing vendors) or Connect (Fuel Me manages ordering and vendor routing):

• Network & Coverage: vetted suppliers that offer the right winter blends in each market, with automatic backup if one can't deliver.

• Visibility & Analytics: track winterized fuel usage, exceptions, and costs by site or region, with exportable dashboards.

• Audit & Compliance: every invoice checked against contracted rates and drop tickets, so a gel event or emergency reroute doesn't turn into a billing dispute later.

• AI Optimization: Octane spots consumption anomalies early, like a tank burning through fuel faster than expected in a cold snap.

Two add-ons matter most for winter specifically:

• FuelRadar: tracks severe weather across every site and adds a buffer to your reorder thresholds, so tanks refill earlier ahead of a cold snap instead of hitting minimum on a normal schedule.

• FuelEvent: run a fast competitive bid to lock in winter blend specs, SLAs, and pricing before the season gets underway, or to respond quickly if a gel event or supply hiccup hits mid-winter.

FuelRescue stays available for standby and emergency response if a site runs into trouble despite the prep work.

Related: Bulk Fuel Delivery · Onsite Tank Fueling · Mobile Fleet Fueling · Generator Fueling