So I checked the BEST data.txt to see why these month data had such large error bars, and were so out of line. (realclimate.org)
Large error bars because it was a CROSSOVER study, although it still managed to reach statistical significance. (caloriesproper.com)
Re # 33, there are still large error bars in temperature rises due to soot, black carbon and aerosoles and hence temperature rise predictions are cautionary in nature. (realclimate.org)