Napoleon through Squealer was always blaming Snowball for every little difficulty in the farm and convinced the animals that Snowball was with Jones all along.
Squealer further put blame on Snowball with the alleged poisoning.
Squealer made up an excuse that Napoleon got sick from poison put by Snowball because he knew Napoleon was just drunk and would not die.
I guess the sort of info you would look for would be the temperature, how sunny/cloudy it will be, and what the weather will be like at that certain time.
