Just mentally factor out the noise. It's easy to interpolate climate patterns from the map. -SW Monsoon peaks late summer/early fall. -Immediate east coast rainfall peaks with Atlantic SSTs, New England nor'easters deliver most precip in transitional seasons. -NPAC jet is most-consolidated in late fall/early winter, then slides south/varies later in winter as mid-latitude waters cool and the thermal gradient relaxes. -Great Lakes' thermal inertia delays peak in temps/rainfall in the downstream vicinity. -The Gulf of Mexico/Continental temperature gradient is an important governor of interior SE US rainfall. -Much of US sees its most intense convective rainfall around the summer solstice, when sun angles are highest. -More moisture available to upper intermountain west in Spring, with residual late-winter jet dynamics and some warm season moisture transport.