How is it today?是問天氣嗎?

(1)It means how do you pass your day today !
----What do you encounter on passing your day today !
----"how" is an adverb.Now in what way; by what means refers to people in your office treating and hitting you today.
---In what condition; to what degree refers to work,office work in your office treating heavily,severely, too much on your mind today.
----They are in direct contact or depending on your office environment question,which you have to answer yourself.With the help of colleagues,friends living, surrounding, relating to your office, you can say"social---social" as a matter of courtesy, of politeness, of manners , of act of civility etc.
(2)Yes it can be exchanged; you are affected by weather ; read your daily report of weather forcast as long as you" come safely through " in life !!!!!
eg;-Q:How is the weather? A:It is a sunny day.
eg:-Q:-What is the weather like? A:-It is hot.

麗靜大大 在學英語時候 好像就忘記了 "人"類的習慣?

1.很多以問句形態的問候語 是 "不期待回答"的!

就如台灣人愛問的,"妳吃飽沒".並不是在問"你的晚餐".所以有很多人就回答"好久不見了!你好嗎?"這樣的習慣 在英語也存在!

How is it today!

也許只是 break the ice的問候語.根本沒有要跟你說天氣的意圖!

2015-07-14 00:55:51 補充：
2. 問候語 的真正含意 要看動作 與上下文.

當上下文是在說"天氣"時,How is it today! 就有可能是在說天氣.
當上下文是在說"生意"時,How is it today! 就有可能是在說生意.

2015-07-14 00:58:27 補充：
學英語 you need to keep your common senses 學到"無感"的程度,豈不是浪費力氣?

2015-07-14 01:05:51 補充：
注意: "回答"與"回應"是有差別的.
問候語 通常 只期待 "回應" 而不期待"回答".
"妳吃飽沒"不是期待 任何關於`晚餐"的回答.

1. How is it today 的意思是說今天過的怎麼樣，並不是問天氣喔
如果有人問你How is it today?你可以說it's good today ，就只是單純問你今天過的怎麼樣喔
2. 可以替換喔，是一樣的意思
希望有幫到你，我現在是在美國留學，英文還算不錯