Climate Summary 
After the cool conditions for much of May, June temperatures have rebounded closer to normal for the first three weeks of the month. A few northern counties have continued with below normal temperatures (1-2°F), while southeast Ohio is running a bit above average. The precipitation story has been rather complex. Much of the state is running above average (Figure 1 – green shading), with precipitation totals in the 5 to 10 inch range across northeast, southeast, and south central Ohio. On the other hand, the bulk of counties in north central, west central, and northwest Ohio have underperformed over the last 30 days (Figure 1 – brown shading), receiving 2.5 to 4 inches over this period. Overall, growing degree days (GDD) since May 1 are running in the 600-900 range, up to 80 GDDs below normal for this time of year. For the latest up-to-date conditions, seasonal outlooks, and monthly climate summaries, please visit the State Climate Office of Ohio.
Weather Forecast
Earlier this month, we questioned how long the cool pattern would last. Well, we have our answer. Heat Advisories and Excessive Heat Warnings have taken over the weather headlines this week, as the season’s first major heatwave takes hold. Strong high pressure has dominated our region since the weekend, allowing temperatures to climb well into the 90s. With plenty of moisture at the surface, dewpoint temperatures have climbed into the 70s, creating uncomfortable conditions. This general pattern will remain in place this week, but the high will shift a bit farther south. This will allow a frontal boundary to sag south into northern Ohio, which could help provide a focal point for scattered showers and storms across the state beginning late Tuesday. Scattered showers and storms are possible throughout the week, and a few of these storms could be strong to severe. Temperatures will be hot, with highs generally in the low to mid-90s across the state through Friday. Southern counties may top out in the upper 90s. Overnight lows will offer little relief, falling only into the low to mid-70s. By the weekend, temperatures may drop a few degrees with highs in the mid-80s to low-90s. Overall, the National Weather Service is currently forecasting 0.25-0.50 inches of rain across southern Ohio and 0.50-1.50 inches across northern Ohio (Figure 2). A few locations may see much heavier totals where thunderstorms occur and meander or stall over the area.
The 8-14 day outlook from the Climate Prediction Center for the period of July 1 – 7 and the 16-Day Rainfall Outlook from NOAA/NWS/Ohio River Forecast Center show near normal temperatures and precipitation are likely (Figure 3). Climate averages include a high-temperature range of 81-86°F, a low-temperature range of 60-65°F, and weekly total precipitation of 0.90-1.15 inches. The initial outlooks for July and the July–September periods show temperature and precipitation near or learning toward warmer and wetter than average. 