Those seem like really low homicide rates...
But I guess I am biased because I grew up near New Orleans where the murder rate is 10 to 15 times higher than that.
http://modiphy.dnsconnect.net/~nolaipm/main/uploads/File/All/BJA_report_on_crime.pdf
page 4/5: new orleans homicide rate for 2009 is about 520 per million
Note that I believe the "total counts" only count the municipality of New Orleans proper, rather than the New orleans metro area where we had annual body counts in the thousands back in the early 90's.
Yeah, the south generally has very big crime issues, it's generally thought to be linked to being next to Mexico. As a general rule of thumb, the further north you go the less violent crime you tend to see. Cities also generally have higher crime rates, so going by that logic it makes sense that New Orleans would have some real huge crime issues. This kind of thing is a really big thing for sociologists.
Next to... Mexico? Louisiana has Texas between it and Mexico, so it's... kinda' far. If I had to wager for a major reason crime's worse in the south-east, it'd be because the tri-state area (north Florida, Alabama, Georgia) is one of the absolute heaviest drug trafficking areas in the USA, from what I understand. There are a
lot of narcotics moving through th'rural areas around here, and some of the cities have... problems. That much crime (much of it organized pretty strongly, from what I ken) tends to radiate a bit.
And yeah, iirc we do get violence spikes in the summer. Considering it's goddamn miserable down here during that period of time, that's not much of a surprise.