Realm laggy and weather differs from players

My realm started to lag a lot in the past 2 weeks. Every member in it is complaining. Weather also doesn't work properly. One of my friend had raining but the other got sunny. We tried to check through attacking with a fire aspect sword. 1 of them ended taking fire damage in the rain. We tested it on sheeps as well, they dropped cooked mutton instead of raw. But after relogging, it changes into rainy weather. The lag causes our screens to see other players teleport from places to places. There's also some delay to our bow shots. It's so laggy. Please fix it soon