The considerations for determining the right size solar panel boil down to the power consumption (wattage) of the electronics (such as light fixtures), how long it needs to be on each day/night, and the sun levels in your area. There are data stations around the world that store solar levels throughout the year. We can access the data and calculate the solar panel requirements for the system at your location. Since the sun levels in most places are at their worst in winter, we determine system requirements based on winter conditions. If we power the light fixtures from dusk to dawn, we will determine the length of the night based on the longest night of the year, which is December 21, aka the winter solstice.
As you can imagine, some places may have better sunlight levels than others. To accommodate the lower sun levels in places like the northern United States and Canada, we offer larger solar panels. In these places, not only is the sun lower in winter, but the days are also shorter, so the solar panels have less opportunity to absorb sunlight. For example, in Fort Myers, Florida, the size of a solar panel required to hold a 10-watt light for 14 hours is about 45 watts. In Chicago, Illinois, a suitable panel for the same light and the same lighting time is a 75-watt solar panel.
In addition to the need for larger solar panels, how the panels are installed is also important. The further north the solar panels are, the steeper the solar panels are installed. To maximize the performance of solar panels during winter (the worst time for solar energy), solar panels should be installed at 15° plus the latitude of the installation location. For example, if you are installing solar panels for an off-grid solar system in Chicago, Illinois, the ideal angle for the solar panels is about 100 degrees.
So in the end, yes, solar will work where you live. As long as your solar system is the right size and your solar panels are installed correctly, you can have a reliable solar lighting system.