The bias to name, because it is the one that gets people hurt: everything that makes turning back feel expensive is already spent.
The months of planning, the travel, the two days walked, the annual leave. None of it can be recovered by continuing. The only question available is what the next section costs and what it gives you, and the past is not on either side of that.
This is hard to feel and easy to state, which is exactly why writing conditions down in advance works - you make the call before the sunk cost exists.
Some things that help in the moment:
Ask what you would advise someone else in the same position. People are consistently better at this from the outside.
Ask whether you would start today, from here, into that forecast, if you had just arrived. If no, that is your answer.
Notice who is arguing. If you are constructing reasons to continue, that is a signal. Genuinely good conditions do not need an argument.
And on regret: turning back and being unsure is the normal outcome and it costs nothing. The alternative, continuing and being unsure, is the same uncertainty in a much worse place. You never get to find out what the other branch held, which is why the decision has to be made on the information you had, not on what happened afterwards.