Even in production work, the atmospheric temperature doesn't factor much into flow rates downstream of separators. A far bigger concern is the formation of hydrates forming when shifting from a high-pressure low-volume containment to the opposite. Commercial sales lines have already had produced water separated from it and mercaptan added. Aside from small risers for servicing, these lines are all buried below frost lines. Even in Alaska, where natural gas lines are elevated for hundreds of miles, gas lines do not freeze, despite not having heat tracing.