I have just bought and planted my annuals in pots, just like many other folks. I think I have done a great job getting them acclimated to their new environs. I even put some large shell pieces from beach trips of yesteryear at the bottom of the planter. Then, we had two days of such heavy rain with such cool temps that some of the leaves are already looking overwatered.
Once annuals are overwatered, you can usually expect a sad, progressive decline of your herbaceous investment. That is unless you can move those heavy, soaked planters to a more sunny location. In some areas of Reston, this might be very difficult due to the heavy tree cover. I personally have very few spots where I can sustain annuals for more than 3 hours per day. Sometimes I just wish I lived where I could plant annuals that are labeled as - "Sun!" Lucky people who can grow in the sun.
In my vegetable garden - with its excellent organic material content and extraordinarily good sunshine delivery - the soil will retain the water for an extra long time with the cool temperatures. With the cool temps and cloud cover, those plants might also be subject to overwatering.
Remember your biology lessons: plants need oxygen to reach the root systems. If it does not get enough oxygen and water is swamping those fine root hairs, the plant cannot survive.
Even though we are enjoying these temps, your plants might be suffering. So, keep an eye on your plants for any side effects of heavy rain. Warm temps and sunlight might just be what they need to flourish!