INDIANAPOLIS | CGN News’ Weekly Weather Brief for 28 June–5 July 2026 tracks a dangerous heat wave across the Midwest, Great Lakes, Ohio Valley, Tennessee Valley and East Coast, along with holiday-week thunderstorm risks, wildfire-smoke concerns in parts of the West, tropical-season storms in Florida and the Gulf Coast, and active monsoon rain in Mumbai.
Update note, 30 June 2026: This briefing has been updated for CGN’s 50-city weather list and adds the six affiliate meteorologists to the source credit line. Forecast details below focus on the active portion of the 28 June–5 July planning period.
National planning headline
Heat is the highest-impact signal. Official heat alerts and forecast highs near or above the upper 90s affect several major population centers, including Chicago, Des Moines, St. Louis, Kansas City, Detroit, Grand Rapids, Cleveland, Louisville, Lexington, Nashville, New York, Philadelphia and Washington. Outdoor work, public events, pets, children, older adults and people without reliable cooling need extra attention through the middle and late part of the week.
The second concern is timing: the hottest stretch overlaps with the Independence Day travel and events window in the United States. Many cities will not be completely dry. Afternoon and evening thunderstorms may interrupt outdoor plans from the Great Lakes and Ohio Valley to the Southeast, Florida, the Gulf Coast and parts of the Plains. Lightning, brief downpours, gusty winds and heavy rain are the main practical hazards where storms develop.
50-city forecast
Indianapolis: Hot and very humid conditions build early, with highs rising from around 90°F Monday to the mid- and upper 90s Tuesday and Wednesday before easing toward the upper 80s by the weekend. Thunderstorm chances increase Thursday through Sunday. Planning: Heat precautions are the main issue early; keep shelter options ready for July 4 weekend storms.
Valparaiso: Northwest Indiana stays hot and humid, with highs mostly near 89–95°F and the hottest stretch Tuesday through Thursday. Thunderstorm risk increases late week. Planning: Outdoor work and youth sports should avoid peak afternoon heat where possible.
Chicago: Chicago faces a dangerous heat period, with highs in the mid-90s through Thursday before temperatures ease into the 80s by the weekend. Storm chances increase Thursday and Friday, with humidity lingering. Planning: Heat alerts, cooling access and checks on vulnerable residents are the priority through midweek.
Des Moines: Central Iowa remains hot and humid, with highs near 90–94°F through Saturday and a possible thunderstorm Sunday. Planning: Several days of high heat and poor overnight relief create cumulative heat stress.
St. Louis: The St. Louis area stays dangerously hot, with highs in the mid- to upper 90s most of the week and heat-index concerns continuing through the workweek. Storm chances appear Thursday and Friday. Planning: Heat is the dominant hazard; holiday events need water, shade and cooling plans.
Kansas City: Kansas City remains very warm to hot, with highs mainly in the mid-90s and humid conditions through Saturday before a slight easing Sunday. Planning: Prolonged heat and warm nights will be more important than daily temperature alone.
Springfield: Southwest Missouri stays very warm, with highs near 90–94°F and isolated thunderstorm chances Thursday, Friday and Saturday. Planning: Heat precautions remain necessary, but storm coverage looks more scattered.
Tecumseh: The Ozarks stay hot and humid, with highs around 90–96°F and afternoon thunderstorm chances Thursday through Saturday. Planning: Outdoor recreation should account for heat early and lightning risk late in the day.
Wichita: Wichita keeps breezy, very warm weather, with highs in the low to upper 90s and a stronger thunderstorm risk Thursday. Planning: Thursday is the main storm-watch day; Friday and Saturday trend hotter again.
Detroit: Southeast Michigan faces a dangerous heat surge, with highs near 97–100°F Tuesday through Thursday before storms and lower temperatures arrive Friday and Saturday. Planning: Cooling access and limiting afternoon exertion are the main concerns.
Grand Rapids: West Michigan stays hot and humid through Thursday, with highs in the mid- to upper 90s before storm chances and cooler readings arrive Friday and Saturday. Planning: The most stressful heat is Tuesday through Thursday.
Cleveland: Cleveland begins the week near the lake-modified lower 80s, then heats into the low to mid-90s Tuesday through Thursday with humidity and late-week storm chances. Planning: Heat alerts are the main concern midweek; lakefront plans still need storm backup later.
Columbus: Central Ohio reaches the mid- to upper 90s Tuesday through Thursday, with storm chances returning Friday through Sunday. Planning: Dangerous heat comes before a humid, stormier holiday weekend pattern.
Cincinnati: Cincinnati runs hot and humid, with highs near 95–98°F Tuesday through Thursday and thunderstorm chances late week. Planning: Heat is the first hazard; lightning becomes more important by Friday and Saturday.
Milwaukee: Milwaukee starts hot, then eases from the 90s into the lower 80s by the weekend as thunderstorm chances arrive Thursday through Saturday. Planning: Midweek heat alerts are the concern before cooler lake-influenced air arrives.
Madison: Madison stays hot and humid early, with highs in the low 90s Monday through Wednesday, then drops into the 80s with thunderstorms possible Thursday through Saturday. Planning: Heat and then storm timing are the two planning issues.
Minneapolis–St. Paul: The Twin Cities remain hot and humid early, then trend slightly cooler with several thunderstorm chances from Tuesday through Sunday. Planning: Heat alerts are front-loaded; storms may affect midweek and weekend plans.
Omaha: Omaha stays hot, with highs in the low to mid-90s most days and a stronger thunderstorm risk Thursday. Planning: Heat warnings early in the week should be taken seriously, especially for outdoor workers and events.
Fargo: Fargo transitions from early severe-storm risk into a warm, less humid but still unsettled pattern, with highs mostly in the 80s and storm chances returning at times. Planning: Watch early-week warnings closely, then keep an eye on afternoon storms later in the period.
Sioux Falls: Sioux Falls begins hot and stormy, with highs near 94°F Monday and several later-day thunderstorm chances through the weekend. Planning: Wind, hail and lightning are the near-term concerns, followed by continued heat and humidity.
Louisville: Louisville faces dangerous heat, with highs around 95–96°F Monday through Thursday and continued humid storm chances through the weekend. Planning: Heat alerts and warm nights create a cumulative risk.
Lexington: Lexington remains hot and humid, with highs in the mid-90s through Thursday and storms possible Friday through Sunday. Planning: The main risk is heat through midweek, then thunderstorm interruptions around holiday plans.
Nashville: Nashville is one of the hottest points in the brief, with highs near 97–100°F through Friday and storm chances from Wednesday onward. Planning: Outdoor holiday preparations should be shifted away from peak afternoon heat.
Memphis: Memphis stays hazy, hot and humid, with highs mainly in the mid- to upper 90s and afternoon storm chances Wednesday through Sunday. Planning: Heat stress will remain a daily concern even when storms are scattered.
New York: New York City turns very hot late week, with highs near 95–100°F Wednesday through Friday and a heavy thunderstorm risk Saturday. Planning: Heat may be the main health issue before storms affect July 4 outdoor plans.
Boston: Boston warms sharply after a pleasant start, with highs rising into the mid- and upper 90s Thursday and Friday and thunderstorm chances Tuesday through Saturday. Planning: The late-week heat could be dangerous where air conditioning is limited.
Philadelphia: Philadelphia faces a major heat signal, with highs near 98–101°F Wednesday through Friday and storm chances by Saturday. Planning: The city should prepare for dangerous heat followed by possible holiday thunderstorm disruptions.
Pittsburgh: Pittsburgh heats into the mid- and upper 90s Tuesday through Friday, then keeps humid storm chances into the weekend. Planning: Heat and thunderstorm timing both matter for holiday travel.
Washington: Washington faces very hot conditions, with highs near 98–101°F Wednesday through Friday and a heavy thunderstorm risk Saturday. Planning: Heat precautions are essential for outdoor monuments, events and travel queues.
Norfolk: Norfolk starts more moderate, then heats sharply, with highs climbing into the upper 90s and near 101°F Friday. Storms become possible Saturday and Sunday. Planning: Heat, humidity and coastal outdoor exposure are the main risks late week.
Raleigh: Raleigh trends very hot, with highs near 100°F Thursday through Sunday and scattered storm chances. Planning: Afternoon heat will be dangerous for outdoor work and youth sports.
Myrtle Beach: Myrtle Beach stays humid with highs mostly in the upper 80s to lower 90s. Early storms are possible, then the pattern looks sunnier and humid. Planning: Beach plans need heat, hydration and lightning awareness.
Miami: Miami keeps a tropical-season pattern, with highs near 88–93°F and daily shower or thunderstorm chances through Sunday. Planning: Lightning safety and quick shelter matter even when rain coverage is scattered.
Tampa: Tampa stays humid with highs near 90–95°F and daily afternoon thunderstorms, including heavier downpours Tuesday. Planning: Brief roadway flooding is possible where storms repeat over poor-drainage areas.
Orlando: Orlando remains hot and stormy, with highs in the low to mid-90s and frequent afternoon thunderstorm chances. Planning: Theme-park and outdoor plans need lightning delays and rain gear built in.
Baton Rouge: Baton Rouge stays hot and humid, with highs near 91–96°F and daily thunderstorm chances Tuesday through Sunday. Planning: Heat comes first, then heavy downpours and lightning may affect afternoon travel.
Atlanta: Atlanta stays warm to hot, with highs in the low to mid-90s and scattered thunderstorm chances late week into Saturday. Planning: Heat precautions and flexible outdoor-event timing remain important.
Dallas: Dallas stays very warm to hot, with highs near 97–100°F and a thunderstorm chance Sunday. Planning: Heat is the main issue all week, especially around July 4 outdoor festivities.
Denver: Denver has hazy, warm conditions with wildfire smoke at times and highs mainly near 89–97°F. Spotty storms are possible Tuesday, Saturday and Sunday. Planning: Air quality and heat matter more than widespread rain.
Salt Lake City: Salt Lake City starts cooler, then warms steadily from the 70s into the 90s by the weekend, with a small shower chance Friday. Planning: Heat increases later in the week; smoke or haze may still affect visibility.
Las Vegas: Las Vegas warms from the mid-90s into the 100s, with highs near 108°F by Sunday. Planning: Heat risk increases each day; afternoon outdoor activity should be minimized.
Phoenix: Phoenix remains very hot, with highs near 102–108°F and fire-weather concerns early in the week from gusty winds, dry brush and low humidity. Planning: Heat safety and fire prevention are the main concerns.
Los Angeles: Los Angeles stays mild and mostly dry, with morning low clouds giving way to sun and highs generally in the mid- to upper 70s, near 80°F Friday. Planning: This is one of the steadier U.S. forecasts, with marine-layer timing the main daily issue.
Seattle: Seattle stays cool to mild, with highs in the mid-60s early and lower to mid-70s by the weekend. Planning: Cloud cover is the main feature; late-week and weekend conditions improve for outdoor plans.
London: London stays mild to warm, with highs generally 23–28°C and the warmest conditions Friday through Sunday. Planning: This is not a bureau-credit change; only the forecast city remains in the 50-city weather list.
Sydney: Sydney has a winter pattern with highs around 15–23°C, a breezy and sunny midweek, and rain increasing just beyond the period. Planning: Thursday and Friday look favorable; Sunday trends cooler and partly sunny.
Hong Kong: Hong Kong remains cloudy and unsettled, with highs around 25–27°C and rain or thunderstorms most days through Sunday. Planning: Residents should watch official rainstorm and heat guidance where active.
Rio de Janeiro: Rio begins warm, with highs near 26–29°C, then turns cooler and wetter Friday through Sunday as showers and coastal-wind concerns increase. Planning: Friday is the main transition day, with lower temperatures and coastal wind alerts possible.
Manila: Manila stays humid with highs near 32–34°C and daily thunderstorm chances through Sunday. Planning: Lightning and downpours may disrupt commuting, school and outdoor events.
Mumbai: Mumbai faces persistent monsoon rain, with highs near 28–31°C and rain heavy at times Wednesday through Saturday. Planning: Road, rail, drainage and coastal-travel updates should be checked frequently.
Forecast confidence generally decreases later in the period. Readers should check official local watches, warnings, transport updates, heat guidance, flood statements and air-quality information before travel, outdoor work, holiday events or major public gatherings.
Additional Reporting By: National Weather Service; NOAA; Open-Meteo; AccuWeather; Met Office; Australian Bureau of Meteorology; Hong Kong Observatory; Instituto Nacional de Meteorologia; India Meteorological Department; PAGASA; Jessica Storm; Elise Navarro; Mateo Reyes; Sofia Kaplan; Malik Harris; Mason Thibodeaux; Noah Bennett