MISO spends July breaking out, but August is different. The Great Lakes take some heat off the top, our forecast moves closer to market consensus, and new gas capacity starts reshaping South flows. Here’s what that means for your August positions.
Heat stays bullish, but the peaks soften
Above-average temperatures continue into August, consistent with both analog years. The 2023 analog shows roughly 15% of the month above 95°F across the broader region. The heat picture stays bullish.
The difference from July is the Great Lakes. That cool surface influence remains a mild moderating factor for the northern footprint, so peak loads may not reach the same sustained levels as July. You still get heat. You just get fewer of the extreme sustained peaks that define MISO’s hottest month.
Where the forecast meets the market
August is where our view converges with the market. The base case Indy Hub heat rate is approximately 23.4, against a market near 24.7, so we sit slightly below consensus. As the Great Lakes influence moderates the most extreme peaks, price formation moves toward the flatter part of the stack.
Put that in context. Last summer’s Indy Hub August heat rate settled at 15.56, reflecting a cool, wet 2025. A 23.4 base case is materially higher, and the more bullish Midwest congestion is already baked into the forecast.
Congestion has its own August signature. Bunsen-Eugene and Worthing-Morone outages come into focus. The Coco-Tipton path, which discounts to Indy on windy periods, works against Douglas-Frank, which leans bullish for Indy per Panorama modeling. That tension creates an intraday signal worth watching.
New supply changes the South
MISO is adding gas this summer, in contrast to PJM. The Orange County Advanced Power Station, roughly 1.2 GW of CCGT in a 2×1 configuration east of Beaumont, Texas, targets a June 30 COD in the Entergy footprint. Once online, it raises south-to-north power flow risk in MISO South on lighter load days, and it begins to replace the retiring Sabine unit. Magnolia Unit 2 adds more combined-cycle support in the South.
Watch the load signal too. On-peak growth is under 1%, but off-peak is approaching 2%. That off-peak figure matches the early data center pattern seen in ERCOT and PJM, where 24/7 loads show up off-peak first. MISO South has drawn real hyperscaler attention, so treat the off-peak trend as a leading indicator.
See MISO’s full price, congestion, and new-build outlook in our Summer 2026 Power Market Outlook.
