Summer is here. You may tell me that it arrived almost three months ago, but for me summer is signified by one thing and one thing only: Produce. Fresh corn and zucchini; blueberries and blackberries; cucumber and peppers. We have entered the height of the summer harvest and it is a beautiful thing.

Due in part to weather conditions, three of my favorite summer ingredients have overlapped more than usual this year: Tomatoes, peaches and watermelon. These particular gifts from summer's cupboard are so delicious, so ephemeral and so connected to the season that when they're around, we should eat them until we are absolutely sick of them. In the Food & Flavor section this week, you'll find some ways to enjoy these ingredients at home. But there's never going to be a better time to visit Pittsburgh restaurants that pay more than lip-service to cooking seasonally with local ingredients.

Legume Bistro in Regent Square is arguably Pittsburgh's most seasonally driven restaurant. Chef-owner Trevett Hooper gets produce from Mildreds' Daughters Urban Farm, Kistaco Farms, Hi-View Gardens, Grow Pittsburgh, Greenawalt Farms and more. He buys directly from farms, and supplements those purchases with frequent visits to the East Liberty Saturday market.

Legume's small and ever-changing menu is always a snapshot of the seasons, and in the summertime, Hooper is able to spend more time seeking out ingredients, because preparing the food is slightly less labor-intensive. He explained, "Right now I'm not really making veal stock, I'm barely using chicken stock, so there's other things I don't need to do as much." So what's on Legume's menu?

"Right now we're pretty much using as many tomatoes as we can," Hooper admitted, and a quick scan reveals that tomatoes of one variety or another grace almost every dish. Mostly, they play a supporting role, but Hooper has put his own spin on that summer classic, the tomato salad: "We take like three or four or five different types of heirloom tomatoes with some good olive oil, balsamic, fleur de sel, toss it all together, then we put a little spoonful of our homemade ricotta and a little bit of cooked farro on there and basil. Very traditional flavors, but they're just exciting because everything's at its peak."

Chef Kevin Sousa at the Red Room may be more well known for his cutting-edge techniques, but he's also intensely devoted to cooking seasonally. His version of the tomato salad is notable for using all three of our theme ingredients. At the moment, the salad usually includes "a mix of local heirlooms, pickled watermelon rind, watermelon-habenero sorbet, compressed rhubarb, tomato water, a small amount of pecorino and then a truffled compressed peach. It's summer-tastic," enthused Sousa.

The combination of tomatoes and watermelon is a fairly recent dining trend that chefs are having a lot of fun with. Sousa agreed, noting, "It's just blown up ... I think people are starting to appreciate the sweetness more. I think they're looking at [tomatoes] less as vegetables, and more as fruit. Not all heirloom tomatoes are super-acidic."

Palate Bistro Downtown is currently serving a tomato-watermelon gazpacho, topped with olive-oil sorbet.

While chefs are embracing the tomato's sweet side, they also seem intrigued by the role watermelon can play in more savory dishes. At Six Penn Kitchen, the grilled watermelon salad, with mixed greens, crispy prosciutto, feta and honey-balsamic dressing, was the result of a concept Chef Keith Fuller had been working on for a while.

He takes a little oil, salt and pepper and a pinch of sugar and brushes it across the watermelon, then places it on the grill. The sugars caramelize, giving the watermelon a smokier, more savory taste.

At Isabela on Grandview, Chef Daniel Leiphart complements honey-glazed blue marlin with fresh watermelon, pickled watermelon rind and a mint gastrique.

Next to all this experimentation, my third favorite ingredient almost seems a little staid, yet I don't think I'll ever tire of getting a dessert list that includes some fabulous peach concoction at the height of the season. Peaches from Kistaco Farms and McConnell's Farms have been a staple of Legume's recent dessert list, usually in the form of short cake or crumble. At Le Pommier, where the peaches are from the Penn's Corner Farm Alliance, they're spreading crepes with a housemade peach compote, topping them with a sauce of peach butter and serving them with chamomile ice cream.

These are only a few of the exciting, seasonal dishes on these restaurants' menus, and only a few of the growing number of Pittsburgh restaurants that are committed to serving local, seasonal food. As customers have grown more aware, the number of restaurants interested in using local produce has also grown. Some of these restaurants are simply picking up on a new marketing trend, but many are true converts, won over by the quality of the food they are buying.

Want to know whether a chef or manager is genuinely interested in connecting with farms and using local produce? Ask how the weather has been affecting the harvest. All of the chefs I spoke to spontaneously spoke about the way that the weather this summer has affected the produce they're getting in their restaurants.

Neil Stauffer manages the Penn's Corner Farm Alliance, a group of farms (there are currently 20) that band together to supply a wider variety of local foods to community-supported agriculture (CSA) subscribers and restaurants. For the first time this year produce from Penn's Corner was being distributed about evenly between CSA's and restaurants (in past years, restaurants purchased by far the majority of the produce). While sometimes restaurants and customers might feel as if they're competing for the best produce available, the truth is that farmers benefit the most from having both of these markets.

Stauffer explained, "The predictability of CSA is probably an advantage. You know ahead of time what your volume is going to be and farmers have the ability to plan. ... But the diversity of products that the restaurants can use is much higher than with a CSA list."

One of the most convincing reasons I've found for eating food when it is in season and local is that not only is its taste far superior to its January cousin bloated with mileage, but also that this taste is tinged with the bittersweet.

Bill Fuller, the Executive Chef of the Big Burrito Company, and someone who's played a tremendous role in developing Pittsburgh's local food culture, described this feeling as, "knowing it's here and will soon be gone."

These foods taste better because we cannot have them all the time. They also taste better because when we eat them we form connections within a community, connections with the people who make our food and the people who grow our food. Eating local foods is possible year round, even in Pittsburgh, but it happens with particular ease and particular sweetness at this time of year. That is the joy of summer.