I had friends visit a few years back. They stayed in the yard and plugged into a 15 amp outlet approx. 50 feet away. I told them to be careful with their electrical usage because of it. Well, it got hot out enough they needed to use the air conditioner. After they left I noticed my outdoor portch light had stopped working so I took things apart and using that outlet with such heavy current draw melted the connections to the light enough to stop it working.
Even with a 30 amp outlet there will be very high current draw using 2 air conditioners and will likey melt some wires if not cause a fire. I was lucky as my outlet did not cause a fire but it was too close for comfort. Be very careful.