Climates in Shenandoah Valley (precipitation vs. dew point) (snow, averages, temperatures)

[Blimp]

Hi weather folks,

I was recently looking at some climate data for Winchester, for Staunton, and for Charlottesville.

Very surprised to find that while all three towns ("cities" in Virginia) have similar high and low temperatures and dew points in the four seasons, the northern Shenandoah Valley (Winchester) has far less rain than the southern Shenandoah Valley (Staunton, Charlottesville).

Charlottesville isn't technically in the Valley proper, but is a nearby city I am interested in.

Here is the data:

In Winchester, it is 16% (1 in 6 days) likely to rain or snow in January.
In Staunton, it is 26% (1 in 4 days) likely to rain or snow in January.
In Charlottesville, it is 37% (1 in 3 days) likely to rain or snow in January.

In Winchester, it is 22% (1 in 5 days) likely to rain in June.
In Staunton, it is 36% (1 in 3 days) likely to rain in June.
In Charlottesville, it is 47% (1 in 2 days) likely to rain in June.

Ergo, the wettest season in Winchester is drier than the driest season in Staunton.

Are there any geography and climatology buffs who can explain to me why it is so much drier in Winchester and the northern Shenandoah Valley than it is in Staunton, Charlottesville, and the southern Shenandoah Valley?

Also, how is this true while at the same time the dew point is not significantly lower in Winchester? Bizarrely, it remains about the same as Staunton and Charlottesville.

[Sir Goosenseresworthie]

hey my knee jerk response would be something to do with the mountains (i guess this is obvious). i didn't bother looking at a map but Winchester is probably positioned farther east and in more of a rain shadow than Staunton is.

Or Staunton in particular has amplified precipitation because of its position on a western side of a mountain?

btw i used to live near the shenandoah valley. its very beautiful. i had a backyard view of the blue ridge mountains.

now i live in the swamp