Would it be too hot to go to Playa del Carmen, Mexico area from 4/11-4/18 ?

I wouldn't think so. I've been there in August and it did get over 40 degrees Celsius once. But it didn't seem that hot. I wasn't digging ditches after all - I was hanging out by the pool/beach lounging and drinking margaritas. Plus, there is generally a good breeze off the ocean.

Anyhow, you can check out www.wunderground.com for historical weather.

Last year April had an average daytime high of 89 掳F / 31 掳C.

Not too bad at all I'd say. The link below is for Cancun, which should be pretty much the same.

Best time of the year to go. Not too hot in the day and not too cool in the evenings.

No. My family and I went to PCD last spring (close to the same dates), and the weather was perfect. It was nice and hot, but not too hot because of the cool ocean breeze. In the evening, it was perfect shorts temperature, which made for really relaxing evenings with my family. The spring is the time to go to Mexico.
I hope you enjoy your trip

Zaibar, I live in Playa but coming in April beholds a great weather, somewhat windy and hot but not VERY, if you want very hot come over by July/August...and there...you will fry like a lobster in a grill, other than that April is perfect for weddings at the beach or to hang out here and there.

There is a lot to do in Playa and great wild activities to engage and spend a great time...Welcome to Mexico!