Opposite of "under the weather"?

British TV Shows are a good way to learn language. At the moment I'm watching Situation Comedy classic series Black Adder, Season one on DVD format. I learnt a new phrase "under the weather" which is in script in Season 1, episode 5, "Witchsmeller Pursuivant".

My own funny moment down at the real life. It was snowing during pre-season Christmas here in Finland. Some local immigrant said "Hello" to me and then continued his small talk "Bad weather, I've moved to Finland last summer and it's snowing, very horrible weather." I answered him: "Well, I'm under the weather too like you here in winter-time Finland".

I was referring to bad weather but I don't know if he caught the joke. Is there an opposite phrase for "Under the weather". "Ylaepuolella" in Finnish synonym in English translation is something like above, on top, over, upstairs, aloft, overhead.

Is it idiomatic to say "I'm feeling overhead" when my mood is good? Looking for a legit way to express myself feeling good as opposed to "under the weather".

In another joke for feeling overheaded, if it's a legit way to cite like this.

Tall and the Giant man met each others on the street. Tall man began the small-talk daily conversation as strangers:

"Howdy Hootchie-Cootchie, How do you do?" The Giant answered "How Do You Do? I'm feelin' overheaded".

Overhead, or another legit way to express yourself feeling good in a positive way or in a joke when I'm trying to create funny situation comedy? Or in polite manner in daily use in GB England, not in US English.

Solution 1:

as right as rain

In good order or good health, satisfactory, as in He was very ill, but he's right as rain now, or If she'd only worked on it another week everything would have been as right as rain. The allusion in this simile is unclear, but it originated in Britain, where rainy weather is a normal fact of life, and indeed W.L. Phelps wrote, “The expression 'right as rain' must have been invented by an Englishman.” It was first recorded in 1894.

(Dictionary.com)

I'm just posting a lazy answer because I'm a bit under the weather, but I should be (as) right as rain by Sunday, maybe Monday. No later than Tuesday, I'll be better for the weather, at least by Wednesday. I'll probably be as sick as a dog on Thursday and as glorious as a sunbeam on Friday. It's hard to predict.

Solution 2:

A thematically related idiom:

on cloud nine (idiomatic)

Often in the phrase on cloud nine: a state of bliss, elation or happiness.

• He was on cloud nine for days after she agreed to marry him.

[Wiktionary]

Collins Cobuild provides one suggested etymology:

This expression is probably derived from the numbered cloud categories used by the US Weather Bureau. Cloud nine, cumulonimbus, is the highest ....

Nevertheless, it's well known in the UK.

Solution 3:

You asked for British English usage...

In answer to your title...

In the pink

In extremely good health and spirits.

Lexico

Even in Urban Dictionary they have it right for the first entries. After that, it is unsurprisingly a reference to female genitalia.

Solution 4:

This is one of the many, many possible expressions—

In fine fettle

If you say that someone or something is in fine fettle, you mean that they are in very good health or condition.

[Collins Dictionary]