weather / wether / whether are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
weather: (noun) the atmospheric conditions that comprise the state of the atmosphere in terms of temperature and wind and clouds and precipitation. (verb) face and withstand with courage. (verb) cause to slope. (verb) sail to the windward of. (verb) change under the action or influence of the weather.
wether: (noun) male sheep especially a castrated one.
whether: NA
weather: w·EH·dh·er
wether: NA
whether: w·EH·dh·er
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)