Cold weather reduces a drone battery's capacity and increases voltage sag, so the same pack supports a shorter flight. Plan to land with a safe reserve instead of flying until the indicator hits zero. If ice accumulates on a propeller, it degrades lift, thrust, and control, so land rather than continue.
What the cold does to the battery
Low temperature cuts the capacity the pack can deliver and makes the voltage drop more under load. The percentage that looked comfortable in a warm car can sag once the aircraft is drawing current in the air. Flight time gets shorter. The test statement is direct: cold reduces capacity and increases voltage sag, shortening the flight. The opposite claims are wrong. Cold does not increase capacity, and it does not eliminate the need for a reserve.
Section 107.49(d) requires the remote pilot in command, before flight, to ensure that a powered small unmanned aircraft has enough available power for the intended operational time. A summer endurance number pasted into a winter job does not satisfy that check. Warm the pack as the manufacturer describes, expect less time aloft, and shorten the plan. These questions do not set a battery-chemistry temperature limit. Use the aircraft limits you already have, and treat the cold as a loss of endurance.
Cold air is denser than hot air, which can help the rotors produce lift. That aerodynamic fact lives on the density altitude page. It does not cancel the battery loss. A cold morning can be good for the air and poor for the pack at the same time. If you only remember "cold air performs better," you will overestimate endurance. If you only remember the battery, you will misread a density-altitude question. Keep the two effects separate.
The reserve you do not spend
Land with a safe reserve. Do not fly the aircraft until it loses power. Do not delete the reserve from the plan in order to add range. The reserve is what is left for the return, for a hover while you sort out traffic, and for the extra draw if you have to maneuver. Section 107.49(d) is about power for the intended time, and the intended time includes getting the aircraft back to a place you can land it. Zero percent at the far end of the job is not a plan. It is the failure the reserve was there to prevent.
Keep a reserve that finishes the operation with margin. No single leftover percentage is the rule these questions state. Land while power remains, rather than spending the last percent in the air.
The same preflight that checks power also checks the rest of the aircraft. Preflight familiarization is the §107.49 list, including weather, airspace, people on the surface, control links, and secure payloads. Condition for safe operation is the continuing duty if something about the aircraft is no longer fit to fly. A battery that is already sagging on the ground is that kind of finding.
Ice on the propeller
A small unmanned aircraft that picks up ice on a propeller during a cold, moist flight has a performance and control problem. Ice changes the shape of the propeller or the airfoil. It disrupts the airflow, it adds weight, and it impairs lift, thrust, and control. The primary concern is that degradation. It is not "the ice adds weight but thrust and control are unchanged." It is not "only the battery temperature matters, and ice below 400 feet AGL can be ignored." Altitude under the Part 107 limit does not make contaminated blades harmless. A small unmanned aircraft should not be assumed to have ice protection.
The response once ice is forming is to land, not to continue the shot and hope the next pass is cleaner. Avoid the conditions when you can: visible moisture and air cold enough to freeze on the aircraft are a reason to postpone, under the same §107.49 weather assessment. Continuing with a distorted propeller is a controllability decision, separate from how many minutes the battery percentage still shows.
A winter roof inspection
The job is a short roof survey just after sunrise, with the temperature well below the mild day you used to time the battery. You put a warm pack in the aircraft, you brief a shorter flight than the summer number, and you set a point to turn back while a reserve remains. You do not stretch the last orbit because the percentage "might" hold. On the way out you see a rough white edge forming on a propeller in the mist. That is ice changing the blade. You land. You do not stay up because you are under 400 feet, and you do not write the roughness off as a battery-temperature note. After you are down, you look at the blades before you consider another launch.
The trap
The battery item is missed by saying cold increases capacity or cancels the reserve. The reserve item is missed by flying to empty or by spending the reserve for range. The icing item is missed by treating ice as weight only, or as irrelevant below 400 feet, or as a battery story. Cold shortens the pack. Keep a reserve. Ice on a propeller is a reason to land.
Performance items are on the free practice test. The loading and weather lessons are in the course.