I have eight (8) floodlights on my tennis court. I didn't install these, they came with the court.
Questions: Recently, in the evening when it was cold I switched them on and only 3 of the 8 came on. A few days later in the middle of the day when it was warm I switched them on and all of them came on. The normal functionality of the lights is that they slowly get brighter and brighter (as you can see from the attached images) until about 5 minutes has passed when they are fully "powered."
What type of bulbs are these that illuminate slowly? Is it normally behavior that these lights might not work when it's cold (a few degrees above freezing)?