I would be careful about saying most style guides.
For instance, here's what The Chicago Manual of Style (17th ed.), 10.58, says, referring to its own guidance as well the International Symbol of Units (SI) format:
In SI usage as in general usage, a space usually appears between the numeral and any abbreviation or symbol. Contrary to general usage, however, SI usage also stipulates a space before a percentage sign (%) or before a degree symbol used for temperature (compare the advice in the introduction to the table at 10.49). In expressions of degrees, minutes, and seconds, SI usage shows (but does not stipulate) a space between quantities. Many publications do not observe these exceptions, and Chicago does not require them in its publications.
SI style Chicago style
22 °C 22°C
The Canadian Government says:
Note the following conventions for using the degree symbol:
30 °C–50 °C (symbol repeated) but 30±2 °C
–10 to –15 °C not –10–15 °C
300 K not 300°K
10° (of arc)
10.5° or 10.°5 or 10°30’ or 10°30’00’’
mm/degree not mm/° (° not to be used alone in denominator)
The Publication Manual of the American Psychological Association (6th ed.), gives a list of abbreviations for units of measurement in table 4.4 that includes:
°C degree Celsius
°F degree Fehrenheit
That's four pretty well-recognized style guides (or standards of formatting) that indicate the degree symbol should be used.
So, you need to determine which guide you're following and use its guidance.