Lowering ph organicly is a slow painful process. The best long term solution is elemental sulfer. Lime is not a good ideal. You can water with H2o that the ph has been lowered but results are short lived. If in fact the rain caused your ph to climb it should go back down with regular watering. Your ph is not crazy high for an organic outdoor grow. If they are still in small containers just make sure you have good soil when you pot up. Check the PH of your water. Peat will lower your soils ph a little. Elemental sulfer is the way to go for long term fix but it takes a while to see results.
Lowering ph organicly is a slow painful process. The best long term solution is elemental sulfer. Lime is not a good ideal. You can water with H2o that the ph has been lowered but results are short lived. If in fact the rain caused your ph to climb it should go back down with regular watering. Your ph is not crazy high for an organic outdoor grow. If they are still in small containers just make sure you have good soil when you pot up. Check the PH of your water. Peat will lower your soils ph a little. Elemental sulfer is the way to go for long term fix but it takes a while to see results.
After doing a little research I highly doubt that the rain by itself caused your PH to rise. It may have saturated something in your growing medium to cause it to rise. Rain water PH map for your viewing pleasure. https://water.usgs.gov/nwc/NWC/pH/html/ph.html
As you see most in most places across the USA rain water PH is less than 6 and and averages around5 or less. Very few places across the USA have rainfall above 6 and no place near 7. Hope this helps.