My rule of thumb is always to wear a collared shirt. If it's 90 degrees and you're covering high school baseball or early season high school football, nice shorts are fine. Just wear a golf/polo shirt.Not really on topic, but it is embarrassing what some sports people deem acceptable attire when they are representing a news outlet in public.
Some men can wear dress pants/khakis well.
For the men who can't, a pair of moderately expensive, nice dark jeans probably look better. Pair with a button down and a jacket and good shoes. The bigger/taller you are, the more that jacket helps.
If you're a smaller, thinner-waisted man, dress up if you can afford it.