Heat wave arrives in Cleveland this week

• The heat index, which combines both temperature and humidity, could eclipse 101 Tuesday afternoon.

Why it matters: Extreme heat is the top weather-related killer in the U.S., and heat-related impacts — including health risks and lower overnight cooling — are more pronounced in urban areas.

• Nightly temperatures are only expected to dip into the 70s, offering limited relief for those without air conditioning or other cooling measures.

Threat level: Young children, older adults and those with chronic medical conditions are especially susceptible to heat-related illnesses like heat exhaustion and heat stroke.

• Per the National Weather Service (NWS), using a fan to blow air in someone's direction may actually make them hotter if heat index temperatures are above the 90s.

By the numbers: Daily temperature records might fall this week, as could hot streak milestones.

• The hottest days in Cleveland on record for the dates of June 17-21 are 94, 96, 92, 96 and 95, respectively.
• The longest local streak of 90+ degree days was 11, from Aug. 25-Sept. 4, 1953.

The intrigue: The NWS went all the way back to 1994 to find a comparable extreme heat event of this magnitude in the same region.

Context: Human-caused climate change is making heat waves longer, more likely and more intense.

• Studies have shown, in fact, that some heat waves would have been "virtually impossible" to occur without human-caused climate change.

The latest: Cleveland's public pools are open as of last week, but due to staffing shortages, outdoor pools are closed Mondays and Tuesdays.

The bottom line: It's projected to be an unusually hot summer — and this first major heat wave could last until early July.

• Check in on your older relatives and neighbors this week.