Not to be a stickler (ok I like being a stickler) but temperature delta, especially deltas between degrees celsius, should be given in kelvin. A 1.8K difference makes sense. A 1.8C difference would be 274.8 kelvin!

This is probably the most ridiculous comment I've read in the history of this website.

There is no difference in the amount of energy 1 degree Celsius delta and 1 degree Kelvin delta represents.

The only (and I really mean only) difference is how zero energy is defined. It is not possible to have negative energy, and that zero Celsius represents the freezing point of water is an artifact of convenience, not of absolute definition.

Taking differences between degrees Celsius values is absolutely fine.

Ratios are undefined because the Celsius scale has no absolute zero while the Kelvin scale has.

See: https://en.wikipedia.org/wiki/Level_of_measurement

> A 1.8K difference makes sense. A 1.8C difference would be 274.8 kelvin!

I think there was some insight here that went off on a bad tangent leading to a math word-problem mistake, confusing these two:

1. A difference... between [X] and [Y], which is a delta of 1.8°C

2. A difference... between [0°K] and a reading of [1.8°C], which is a delta 274.95°K.

Celsius is not an absolute scale, but that isn't a problem for deltas: (10C - 5C)=5C, (10K-5K)=5K. Celsius is only problematic when multiplying or dividing. 10C is not twice as hot as 5C.

That makes no sense. A difference between a read of 37C and 38.8C is still 1.8C.

Kelvin and Celsius use the same unit magnitudes. It would be a 1.8* difference either way.

"A 1.8C difference" expands as "A difference of 1.8C" expands as, and here's the ambiguity, either:

"An absolute difference of 1.8C, or 274.8K, measured between A and B"

or

"A relative difference of 1.8C, or 1.8K, is added/subtracted to A/B in order to reach B/A"

I don't think the context-free variant with K will improve understanding and decrease confusability in this discussion context, but I appreciate the pointer about it in general. I'll take a lot more care around it in a future thread about space apparel!

To be a stickler, communication requires respect for your audience. The vast majority of everyone understands a 1.8 degree C delta. I would argue that very few people anywhere would understand a temperature delta given in kelvin.

>A 1.8C difference would be 274.8 kelvin!

Categorically and factually incorrect.

A 1.8 degree C different would be 1.8 kelvin. The two degrees have different zero points but one degree Celsius and one degree Kelvin are identical in magnitude.