My truck runs worst when it rains or snows it just dies and it's hard to keep running
Sounds like it needs a general tune-up. When moister gets into electrical parts that are of age such as plug wires, cap & rotor, it will generate a weak spark.
Rowefast is right, especially the with the distributor cap on these fords, for some reason they seem to collect moisture even though they are vented.
Wrap a plastic bag over distributor cap. You have your cooling fan blowing wet air on your distributor which causes sparks to short to ground or across your distributor. Make sure it's wrapped up tight so it doesn't come in contact with extreme hot metal and melt.
When you have new parts, no need to wrap things in plastic. If anything when new parts are installed spray silicone over the ignition parts.
Careful with the silicone spray, if any gets into the intake it can reek havoc with O2 sensors.
Looking for a Used F-150 in your area?
CarGurus has 203,974 nationwide F-150 listings starting at $1,273.
Search Ford F-150 Questions
Ford F-150 Experts