tutorial (language : english)

open Valve Hammer Editor, make a simple map, like a block, then select entity tool (shift+B). choose "envglobal", then put in middle-top on your map. after that, select that object with selection tool (shift+S). then click alt+enter (object properties) on your keyboard. now you'll see "envglobal" in there, change it to "envrain" if you want the weather is rain, and "envsnow" if you want the weather is snow. below the word, there's a 'keyvalues:', on the below there's 'triggermode 0' and 'initialstate 0', now click it 1x, then delete it (you can delete by clicking 'delete' below 'SmartEdit' key). then save it, run map (F9) and enjoy the weather!!

tutorial (language : indonesia)

buka valve hammer editor, buat map yang simpel saja, seperti balok, lalu tekan 'entity tool'(shift+B). pilih "envglobal" lalu letakkan di tengah-atas di map kamu. setelah itu, tekan objek itu menggunakan 'selection tool (shift+S). lalu tekan alt+enter (properti objek) di keyboard-mu, sekarang kamu akan melihat tulisan "envglobal" di sana, ubah menjadi "envrain" jika kamu mau cuacanya hujan, dan "envsnow" jika kamu mau cuacanya salju. dibawah tulisannya, disana ada 'keyvalues:', dibawahnya ada 'triggermode 0' dan 'initialstate 0', sekarang tekan tulisan itu 1x, lalu hapus (kamu bisa menghapusnya dengan menekan tombol 'delete' dibawah tombol 'SmartEdit'). kemudian simpan mapnya, lalu run-map (F9) dan nikmati cuacanya!!

sorry bad english, I'm Indonesian ^^

more info look the render picture