What pattern causes record cold nights in June?

[TheBigOne]

I have seen plenty of days in June were unusal chilly weather happens in the daytime as a result of cloud cover but what causes record lows at night?   What is the pattern and dynamics going on?   Is it the same pattern that causes record cold nights in the winter time only without snow cover?   It seems to not happen very often.

 

Salem amazingly has many sub 40F record lows!  The record low is right around 32F believe it or not but I don't remember where I found the statistics!  All I got were commercial sites on Google like Weather Warehouse wanting to charge tons of money for data 

[snow_wizard]

There a couple of scenarios.  The best bet for record lows this time of year are rather dry cold fronts that have a good northerly wind surge behind them.  That will leave us with a reasonably cool / dry air mass in place.  I have seen a couple of record lows this time year when it rapidly clears out behind a fairly typical cold front also.

[TheBigOne]

Isn't dry cold fronts only a Midwest phenomena?   I didn't think we could get them here.