This week on Science Behind the Forecast, hear why some grapes need near perfect temperatures to produce wine. LPM’s Bill Burton talks about wine grapes with meteorologist Tawana Andrew.This transcript was edited for clarity and length.Tawana Andrew: A very random question for you this morning.Bil l Burton: Okay, I'll see what I can do.TA: Are you a wine man?BB: I will drink wine on occasions, but I have to be honest. My knowledge of wine is pretty slim.TA: Same here, but we're going to talk a little bit more about wine and weather. Let's put it that way.BB: That is our topic today because there are so many crops that are affected by weather. Of course, wine is no different. Grapes are no different. What do we need to know about weather and wine?TA: It's not just weather that impacts the types of grape varieties that can be grown in a certain area, it's everything from the geology to the landscape to the soil to just the overall temperatures that can influence those types of grapes and dictate the yield and the quality of the harvest. Cool climates are really good for pinot grigios and chardonnays, while hotter climates cater to zinfandels and cabernets, globally overall wine grapes are grown in areas where the average growing season temperatures occur in a very narrow range of about 18 degrees Fahrenheit. But for pinot noirs, they are so finicky. The average temperature range for their growing season is much smaller, between two and three degrees Fahrenheit.BB: That's it, two or three degrees?TA: That's it. They are so stubborn and finicky. Like you can only be within that small range. And of course, we've been talking about these crazy wildfires in places like California and France, and these incredible droughts and these high temperatures, and all of that is forcing these winemakers to adapt. When you have daytime highs like what we've been seeing in California over the past week, the fruit may ripen faster and lead to different tasting wines, and the high temperatures and the droughts in California have forced some wineries to even change their practices overall by blending certain grape varieties to keep their flavor that they want, or they've even invested in specialized irrigation to keep their farms going.For the United States, the growing season is between April and October, and since 1970, the average temperature for this time frame has risen about two degrees Fahrenheit. We just talked about pinot noirs. You can't have the growing season temperature vary more than two to three degrees. That's already a big shift for these winemakers, especially in California. Warming temperatures can overall change what vineyards make. They could be producing chardonnay right now and then switch to merlot later.Some winemakers have just been up and moving, especially in the United States, further north or to higher elevations to make sure that they can still produce those same crops.Something that I found incredibly interesting is that wildfires can impact rates by damaging the crops or the equipment. But even if there's a wildfire miles away, if that smoke drifts over a vineyard, it can create a smoky aroma and taste in the grapes. That can completely change the kind of quality that these winemakers can make. So instead of that higher end $30 or $40 bottle, it's more of a boxed wine situation. ...read more read less