Eventually fossil fuels will decline to the point that renewables will have to replace them, and the electric grid become 100% renewable. One of the factors that will make this difficult is that 50 to 90% will need to come from wind and solar, and both wind and solar are seasonal. And so is geothermal, though the amount of power it does or could provide is so trivial that it doesn’t matter, except perhaps for local areas near geothermal hotspots that also have transmission lines.
What follows comes from: NREL. January 2016. Doubling Geothermal Generation Capacity by 2020: A Strategic Analysis. National Renewable Energy Laboratory. Technical Report NREL/TP-6A20-64925
Many geothermal power plants generate less power in the summer. There are several reasons, but the main one is that there is a smaller brine-ambient air temperature differential. [ Though evaporative cooling can help (though I wonder how much extra power this takes).]
As you can see in figure 2 below, most geothermal power is found in the west, especially California.