As others have said, fly in the day before if possible. If not possible, make sure you have travel insurance that includes flight delays and cancellations.
Some reasons why (that I have experienced).
1) flight from LA to Austin, cancelled and first available flight was the following morning.
2) flight from LA to San Jose CA, cancelled (as well as one after it). Luckily because it was a short hop, there was another one even later that they put me on.
3) flight from LA to Vegas, delayed 3 hours sitting on tarmdac because the Air Force One was in Vegas and the air space was closed until it left.
4) same Vegas trip going home, delayed 2 hours due to high winds...full airport shutdown.
5) Different trip LA to Vegas, flight cancelled and had to scramble because the only alternate that day was 1 hour earlier.
6) And even another LA to Vegas, flight delayed 3 hours due to weather delay (fog) at the airport the incoming flight was coming from. **so it doesn't even have to be the weather in your city or where you are going that can delay the flight. It depends on where the plane is prior to your flight.
7) flight from LA to MCO (to board the Dream), about 1 hour delay due to mechanical issues. But they weren't sure it could be fixed and were starting to offer up alternate flights (some going to Miami instead, etc).
And look at recent events in San Francisco and New York. Both of those affected not just flights at that airport but also connecting flights using planes that were stuck on the ground there, etc.
If you can cancel and rebook a day earlier, that would be my suggestion. It is worth it for the piece of mind.