The phrase "however hot" is correct and usable in written English.
You can use it to express an opposing idea or to indicate a contrast. For example, "The sun was shining brightly, however hot it was outside."
However hot the city, there is almost always a breeze by the water.
Below are some behaviours that readers are urged not to undertake, however hot they may become.
And no matter how governments handle multinationals, they will lose them if they do not also try to attract other kinds of money—however "hot".
However hot the day has been, bring warm clothes, mosquito repellent and a couple of torches with fully charged batteries (in case you lose or break the first one).
However "hot" or otherwise, however sexually driven or otherwise a woman might be, she knows she can always get sex – so long as sex is all she wants and she's not too choosy about the partner.
But however hot the afternoon, however tempting the sight of the cool, flowing water, do not even think of getting wet, as touching the water is forbidden at nearly every fountain in the city.
There are, however, hot-strip mills designed for smaller production.
However, hot-embossing revealed a drawback in the following holography process due to the possibility of PR degradation during the elevated heating.
In many important practical applications the interface is, however, hotter than the liquid, unless the liquid looses heat to the gas.
For many people, however, those hot meals are something of an inalienable right.
On release, however, a hot film sells on DVD no matter what the extras.
