I think night racing is definitely a competitor-convenient thought, however a bit difficult to execute.
On the east coast, I know of a few rental tracks that try the headlamp option. Most recent I know of is Summit Point Kart - Capital.
SPK Capital Night Race
On the west coast, Adams Motorsports Park hosted some night races in 2018. But that’s an example of track lighting helping us out.
I think the best way to go about track lighting is with a street light approach much like Adam’s but more so. Especially near each corner. In Adam’s case it was just barely enough imo as a driver. Made for a great light show with different color MyChrons and some drivers adding underglow strips though!
From what I’ve heard from SPK, it was hit or miss with headlamps depending on driver preference.
I’d say for tracks without lighting infrastructure, possibly renting mobile light carts would be an option depending on financial support (most likely most expensive route). Floodlights on stands would be a good option too. Just need to worry bout routing chords and generators and fuel.
From a spectators point of view, summer is going to be a struggle day or night. The heat stunts interest growth for sure. If there’s a way to clearly identify drivers (color LEDs?) maybe that could help family and friends follow along.
Lastly time of day and length. What do kids want to do on a Saturday night on a summer off from school? What do parents prefer to do after a long work week and possible soccer games for other kids?
It’s a challenge all around but I think the heat is a legitimate concern for summer racing. So how can we make it happen so that we keep entries up and spectators interested?