Early June delivered a one-two punch to the Midwest grid. A sustained heat wave drove temperatures above seasonal norms and pushed MISO demand toward levels not seen since winter. Then a line of severe storms tore through the region just as the system was under its greatest strain. The collision of sudden loss of power in some areas and a flood of wind generation in others set off dramatic price swings in the real-time energy market that pushed key hubs to extremes.

Figure 1 | Average Midwest Temperatures and Differences from Normal (May – June 2026)

Figure 1 shows daily average Midwest temperatures from the start of May through June 18^th. The top panel plots the daily average in degrees Fahrenheit, with orange bars marking days that ran above normal and blue bars marking those below; the bottom panel shows the difference from normal (DFN). After a warm stretch in late May that peaked near 75 degrees, temperatures climbed again in early June. The hottest day of the run was June 9th, when the average reached 77 degrees, roughly 9 degrees above normal. That heat set the stage for the demand surge and the storm activity that followed midweek before the pattern finally broke, and temperatures fell back below normal heading into the back half of the month.

Figure 2 | MISO Load Forecasts and Actuals by Region (June 7 – 14, 2026)

Demand forecasts pointed to a strong week, with system-wide peaks expected to top 100 GW on multiple days. The heat arrived but then the storms complicated the picture. As outages spread across the region on Wednesday and Thursday, actual load in key MISO sub-regions began falling short of expectations even as evening peaks remained elevated. The divergence between forecast and actual load, combined with a surge of wind generation in the North, created the conditions for a dramatic market response that unfolded differently on each side of the system.

The full story. including how hub prices in North MISO crashed into negative territory while key Central hubs spiked, and what transmission congestion had to do with it, is covered in depth in Energy GPS’s latest article, “Heat and Havoc in the Heartland.” To read the full analysis and stay ahead of MISO market developments, subscribe to Energy GPS’s MISO power market content. For more information on packages and subscriptions, visit our Market Analytics page or reach out via the Contact Us form on the Energy GPS website.

Follow us on LinkedIn