A recent study of daily rainfall amounts throughout the year published in Geophysical Research Letters shows that for a large part of the world, half of the annual rainfall occurs on just 12 days during the year, with the rest of the rain falling on days with smaller amounts (based on 1999 to 2014). This ratio appears to be mainly independent of where you are. The scientists who discovered this were astounded that half of the rain fell in just 3% of the time, but found it to be generally true. You can read more about it at Gizmodo here.
For fun I tried it out on daily rainfall amounts from Athens GA and found that the ratio did tend to vary a bit from one year to the next, with drier years having half the rain fall in fewer than 12 days (the rain is more concentrated in a few days) and wetter years having half the rain fall on more than 12 days (the rain was more spread out), but as an average, this was surprisingly close. You can do it for your location by downloading daily rainfall data, importing it into a spreadsheet, and sorting it from high to low. If you add up the rainfall for the top 12 wettest days it should be close to 1/2 the annual rainfall total for that year.
