A mid-summer vineyard assessment suggests 2018 is looking like a throwback to the 2000s

I feel like I'm inviting disaster just by typing this sentence, but it's been, well, benign so far this summer.  I got back from two weeks in Europe, some vacation and some work, to find a vineyard significantly advanced over where it was in the first half of June.  Vines that were just finishing flowering are now fully set, with early varieties nearly full-sized.  The Grenache, below, looks fully formed, though the grapes will continue to grow a little and there's no hint of color change yet:

Fruit set looks good, with only minimal shatter, and the late rain that we received in March appears to have given the vines enough vigor to set a healthy crop.  We will surely be dropping some fruit this summer.

The vineyard looks vibrantly healthy, with even stress-prone varieties like Roussanne and Mourvedre still fully green.  This isn't a surprise; we've only had one day (June 22nd) top 100, and only 14 days reach the 90s.  That may sound like a lot, but the average nighttime low since May 1st has been 46 degrees, and a couple of days in mid-June didn't even make it out of the 60s. More measurably, in terms of heat accumulation (as measured in Degree Days at the weather station in our vineyard) we're still below our 20-year average, with May 18% cooler than normal and June just 5% warmer than normal.  I'm not sure if the health of the vineyard comes through in photographs, but it's (no pun intended) worth a shot:

Or, for another perspective, here's a shot from below the Counoise trellises, showing the clusters sheltering beneath their leafy canopy:

How does this compare to other recent years, and what does it mean for harvest?  Well, our late-March budbreak, which kicks off the growing season, was about two weeks later than in most recent years, though more or less average looking at a 20-year perspective.  The weather since then has been quite a bit cooler than the years since 2012, but again, more or less average looking at the 20-year scale.  That's probably easier to make sense of in a graph.  First, the heat accumulation (in degree days) this year versus two averages: one of all years since 1997, and the other looking at just the recent warm stretch that began in 2012:

You can see that our recent years (in green) have been quite a bit warmer than the longer-term average (in blue), whereas 2018 (in red) is cooler.  That's perhaps even more dramatically illustrated by looking at 2018 in terms of percent difference from average.  All three months we've measured this growing season have been between 8.5% and 15.5% cooler than the 2012-2017 stretch:

All this weather data just reinforces my thought that we're going to be seeing a harvest that's more like what we got used to in the 2000s (when we averaged 1069 degree days through June, nearly identical to this year's 1045) than what we've seen in the 2010s. The best comps to date are 2002, 2006, and 2009, all of which didn't see harvest begin until the first half of September. I'm not expecting veraison until we get close to the end of July.  Of course, there's still a long way to go, and there is a hot stretch forecast starting next week.  But we are at what's typically the hottest time of year, and it's still been moderate.  So far, so good.