Even the rain can affect the way your pool runs and stays clean. When it rains and your pool is left open, the rain water dilutes the pool water, which cause the chemical balance to be thrown off. If the rainfall is light where you are located then the water shouldn’t affect your swimming pool that greatly. However, if the rain is heavy and constant then you should be more cautious in watching the water levels and the balance of chemicals in your swimming pool. The disrupted chemical balance could make your swimming pool eventually become unclean, and no one wants an unclean swimming pool.
Here is how to protect your pool from rain storms:
A few ways to prepare your swimming pool from a rain storm is clearing everything from your swimming pool and backyard. Taking pool floats and equipment, like an automatic pool cleaner, out of the swimming pool. As well as pulling all of your patio furniture into a safe dry storage place so it isn’t flying all over your backyard. If there is anything in your backyard that could blow away in the wind or that you do not want to get water damaged, then it should be moved into a dry secure area.
Next, depending on how bad the storm will be, you may want to consider turning off the electric and gas to your swimming pool. This step is just a safety precaution if the weather is predicted to be very severe. Also, putting a pool cover over your pool would be beneficial before the storm starts. Having a pool cover over your swimming pool will help keep out dirt, leaves and any branches that may try to fall into your pool.
Before putting on your pool cover make sure you prepare your pool water. This process is similar to if you were closing up your swimming pool for the winter. Make sure all of your water chemicals are balanced and ready to fight of any additional bacteria 
that the rainfall might bring into your swimming pool.
Cleaning your pool after a rain storm:
After the storm takes place you’ll want to clear your swimming pool of any debris and turn your pool pump on so the water can circulate again. By having your pool pump on and circulating water it helps to clean the water that is just sitting there. You’ll want to clean your swimming pool like you would when you clean your pool weekly for good maintenance. Keeping up with your weekly pool maintenance is the ultimate way to keep your swimming pool clean. Some of these maintenance tasks could be brushing your swimming pool. Having a pool vacuum running to clean up all the dirt and debris and testing your pool water so you know if you need to add any chemicals to your swimming pool. Remember that your swimming pool water can be diluted do to the rain.
