The most common and most likely answer to this crossword clue is the 8 letter word ELEMENTS
I've seen this crossword clue in The Guardian
E
L
E
M
E
N
T
S
More clues leading to the result ELEMENTS
- He is one of them in a chemistry set
- He and I are two guys into remoulding steel
- Steel men work with the likes of carbon, manganese and phosphorus
- He and I, say, heating devices
- People into steel alloy components
- He and I, say, could be factors
- A, B, C etc, as periodically arranged? He and I are with them
- Weathermen caught in a flurry of sleet
- How the weather can heat kettles
- Fundamental principles of weather
Buddy explains!

The straight part
We know that "A, B, /C/ etc/as periodically arranged? He and I are with them/8" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a, b, /c/ etc/as periodically arranged? he and i are with them/8 = elements.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ELEMENTS mean?
ELEMENTS noun- One of the simplest or essential parts or principles of which anything consists, or upon which the constitution or fundamental powers of anything are based.
- A small part of the whole.
- The sky.
- (with "the") Atmospheric forces such as strong winds and rains.
- A place or state of being that an individual or object is best suited to.
- (usually in the plural) The bread and wine taken at Holy Communion.
- A group of people within a larger group having a particular common characteristic.
- A component in electrical equipment, often in the form of a coil, having a high resistance, thereby generating heat when a current is passed through it.
- One of the conceptual objects in a markup language, usually represented in text by tags.
- Outdoor weather, such as wind or rain.
- The basic tenets of an area of knowledge.
- The bread and wine of the Eucharist.