Originally Posted by
Propellerhead
Also, how likely are you to actually divert? If the weather at destination is fine and there’s multiple runways I’d be less likely to take extra fuel for avoiding CBs en-route etc as I know I can likely dispense with the alternate (and probably get a direct routing after weather avoidance). If it’s a single runway, with no ILS in the Caribbean, I would be more cautious.
Yes that's why I work backwards. Start with destination weather. Decide if you see something which makes you believe that you could face a delay for landing. If so take extra fuel for the destination and then be more aware of anything enroute which could use up your contingency.
If weather at destination is fine and more than two runways available then I wouldn't take extra unless I foresee contingency fuel being completely up used up and then some.