"ITS" and "IT'S"
"Its" shows possession. "It's" is a contraction for "it is" or "it has." Ex.: The dog wagged its tail. It's a lovely day outside.
"WEATHER" and "WHETHER"
"Weather" refers to the atmospheric conditions. "Whether" is used to introduce alternatives or choices. Ex.: The weather is perfect for a picnic. I'm not sure whether to wear a jacket or not.
