Traveling from East Hamilton, Ontario to 3001 Hospital Gate in Oakville at different times of the day for a new job. What is the worst case scenario for traveling time at any time of the day, in either direction?
The worst case scenario is that you do not reach your destination at all.
In extreme cases, trains break down completely and travellers are completely stuck for hours. Drivers may be stuck in cars for hours if a severe blizzard hits. Cyclists and pedestrians may head back within minutes when everything is flooded. If a tornado or earthquake destroys the one bridge that all modes of commuting need to use, you can't get there at all.
This applies to all travel by all modes, commuting or not. The worst case scenario of a delay is a cancellation. This might not be the answer you're looking for, but there isn't any answer that is more meaningful.