According to the Climate Prediction Center, the end of October and the beginning of November have a higher chance of being cool and dry than warm and wet.
The eigth- to 14-day temperature outlook has the Midwest under a bull's-eye for below-average temperatures. This is highlighted in the map above in the dark blue area. Based on this outlook from the Climate Prediction Center, Oklahoma has a 50 to 60 percent chance of below-average temperatures.
The average high temperature on Halloween in Oklahoma City is 68 degrees and the record high temperature is 85 degrees set in 1968. The average low temperature on Halloween in Oklahoma City is 47 degrees and the record low temperature of 29 degrees was set in 1954.
If you click on the related content, you can see the Climate Prediction Center has Oklahoma with a higher chance of below-average precipitation, than above-average precipitation.
It may still be a little early for a specific temperature forecast for Halloween in Oklahoma City, but as of now plan for dry, cool weather.