Organizers of the Democratic National Convention are playing the odds in scheduling President Obama's anticipated nominating acceptance speech outdoors Sept. 6 at Bank of America Stadium.

September is among the driest times of year in Charlotte, but it can produce surprises that might not please convention officials and those planning to attend the speech.

A check of National Weather Service records shows rain has fallen four of the last 15 years on Sept. 5 in Charlotte, and it appears as if only two of those incidents happened in the evening hours, when Obama's speech would take place. In neither case was the rainfall heavy.

Most years, Sept. 6 was a dry and fairly hot day in Charlotte.

But the DNC is taking at least a chance on the weather.

Last year, for example, Sept. 5 was a nasty day, with 1.62 inches of rain falling and two thunderstorms reported. In 2004, almost 2 1/2 inches of rain fell on Sept. 7.

Charlotte's record all-time high temperature, 104 degrees, was set on three different dates. One of those was Sept. 6 -- in 1954, before the President was even born.

The real nightmare for the convention can be seen from 1979. That's when Hurricane David moved up the East Coast and pushed inland between Charleston and Savannah on ... yes, Sept. 6. Heavy rain fell in parts of the Charlotte area.

Here is a summary of what to expect on Sept. 6:

Average high: 84 degrees (about 82 degrees at 8 p.m.).

Average high the last 15 years: 86 (about 84 at 8 p.m.).

Average rain the last 15 years: .03 of an inch.

Hottest Sept. 6 the last 15 years: 93 (2007).

Chilliest Sept. 6 the last 15 years: In 2000, the high was only 64 degrees.