While we're closing in on September, several of the global temperature datasets are still stuck on June and haven't released the July data yet. Just for fun, let's compare how the first six months of 2014 stack up to previous years. To answer the question in the title, I averaged the first six months of each year in the Cowtan-Way global temperature dataset.
The first six months of 2014 were the third-hottest such period since 1850 with an average anomaly of 0.588ºC, just edging 1998 (0.585ºC). Only 2010 (0.697ºC) and 2007 (0.626ºC) were hotter.
Top 10 hottest Jan-June periods:
It should be interesting to see how the rest of the year plays out.