If you have a distributor cap, do check it. It's a cheap fix to replace it anyway.

I STILL believe that the ignition coil is your problem, based on my experiences with hard starting in moist weather.

But start with the cap, and then take a look at that coil...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car