Australia uses the metric system for temperature, ie degrees Celsius. The easy rule to convert to Fahrenheit is F=C/5*9+32.
March is the first month of autumn (fall) in the southern hemisphere but it can still be hot. The average maximum temperate for Adelaide in March is 26.1C (with aa average minimum of 15.2C). The highest recorded temperate in March was 43.6C (in 1934) with the lowest being 6.6C (in 1933). The average number of rainy days for March is 5 with an average monthly rainfall of 26mm.
The weather forecast and current weather conditions in Adelaide are available from the Australian Bureau of Meteorology's web site.
The UV index is expected to be either "very high" or "extreme" so bring a wide brimmed hat, sungalsses and SPF 15+ sunscreen. Of course you can also buy those items here.
Note: Daylight saving finishes in Adelaide on Sunday the 26th of March.