Although Halloween is the last day of October, it can be quite warm at this time of year. Here's a perfect example; the high temperature in Bloomington, Indiana was 88F (31C) on Halloween in 1950. I wonder if the residents of Bloomington were screaming "global warming"? :-)
Although records go back to 1871 in Indianapolis, 1954 in Lafayette, and 1895 in Bloomington, my records only go back 12 years to 1997. Nonetheless, the coldest maximum high I've recorded for October 31 was 46F (7C) in 2002. The warmest maximum high was 75F (24C) just one year later in 2003. The coldest low for the day was 35F (2C) in 2006. The warmest low was 63F (17C) in 2003. As for precipitation, I've not recorded any snow in the last 12 years on October 31 and barely any rain. A Trace of rain was recorded in 1997, 0.18" was recorded in 1998, and 0.13" was recorded in 2006.