Each component in the kit will have a different reaction to the temperature but the two that react most notably are the solar panel and the battery bank.
Solar panels perform better at lower temperatures due to the inner workings of the panel. Solar panels are created by using two different types of silicon, called n-type and p-type. N-type silicon has free electrons that want to flow, and P-type silicon has holes that want to accept those electrons. This creates a flow of electrons that are constantly wanting to move, and therefore creates a voltage that is inherent in the cell. These electrons are moved when they are excited by light and heat from the sun. When it is hot, the electrons already possess some amount of power from the surrounding heat, and the amount of power hitting the panel from the sunlight is not as great in comparison. If the surrounding temperature were much lower and the electrons possessed much less energy, the difference between the electrons’ energy and the sunlight hitting the panel will be much larger and the panel will have a higher voltage. Note that this does not change the amount of light that is hitting the panel, but instead raises the efficiency of the panel and allows it to get more out of the same amount of light.
Batteries have pros and cons while operating at opposite ends of the temperature spectrum. When at a high temperature, batteries have a slightly higher capacity but shorten their lifespan at a faster rate. Conversely, when at a low temperature, the maximum useable capacity of a battery decreases but the batteries will have a slightly increased lifespan. Batteries also slowly lose charge over time even when not being used, and this rate of discharge is also slightly sped up with increased temperature.