The weather was nice with the sun
I am going to walk for an hour this morning.
The weather was nice and sunny.
hello. I am English and will try to help.
1. this should be...help me WITH the error please.
2. this should be either..... I'm to walk for one hour OR... I am to walk for one hour.
it is a statement that you are about to walk for one hour. ( in the future.) is that what you meant to say?
if you have already walked, you could say...I walked for one hour today. the sun was shining. the weather was good.
3." the weather was nice with the sun " is ok, BUT not something you would normally say .
maybe " the weather was nice IN the sun".
good luck. I hope I helped you a little.