It's your crazy uncle FarmerDan again. To the question, it all depends...wait, don't wait?
I really think we make a mistake by waiting until a rain to think about planting seeds. I know it seems logical to do that, but here's the thing. If you plant seeds on your schedule, even if it's dry, there are potentially a number of good things happening while the seed waits for the right conditions to germinate. You might not think there's any moisture around your seeds as they sit in the soil. I think you'd be surprised. Little by little that seed is absorbing moisture in anticipation of the big flood it needs to ignite. Remember, a seed has to absorb 40% to 100% of its weight in water before it will start its magical transformation. If it's halfway there when the rain comes it'll shoot out of the ground and establish a solid root before another dry spell hits. If you wait to plant moments before a rain, the seed has to make up the time required for it to absorb enough moisture before it germinates. And if there's not enough time before the next hot, dry period it dies.
Now, I'm not advocating planting during a severe drought, nor in soils that cannot hold a little moisture. In the end, you have to decide, but waiting isn't always the best option.
Planting is always a risk. It's part of the game. Play it as best you can.
Grandpa used to say, "Plant in the dust, your bins will bust. Plant in the mud, your crops will be a dud!"