You can do this through the constructor:
plt.AddScatter(times, temperatures, Color.Blue, lineWidth: lineWidth, markerSize: markerSize)
Based on this example here: https://scottplot.net/cookbook/4.1/category/plottable-scatter-plot/#custom-lines
For what it's worth, setting LineWidth
does work, but it looks like you tried to set the linewidth of the plotting window rather than the actual scatter plot. This should work better:
var plt = new Plot(1000, 500);
var scat = plt.AddScatter(times, temperatures, Color.Blue);
scat.LineWidth = 4;
scat.MarkerSize = markerSize;
If you need more, you might want to check out the ScatterPlot docs. The docs haven't been available for very long unfortunately, but now that they're here they're a great source: https://scottplot.net/doc/v4/api/ScottPlot.Plottable.ScatterPlot.html