Temps are supposed to hit 90°F this week in Napa Valley, where I live, and it’s still technically winter. Forecasters say many states may experience record-smashing heat over the next few days. My advice: yogurt. I don’t have much appetite for cheese in hot weather, but yogurt salads and chilled yogurt soups have a lot of appeal. Yogurt is cool, tart and refreshing, and we know it’s good for us.