SOUTH BEND,IND – A looming heat wave this week is expected to be the hottest stretch in over five years. While the heat index gets many headlines, it’s the highs, lows and mean temperature that goes into the record books.

The mean temperature takes into account the entire temperature range. For example in a dry dessert climate highs can warm into the triple digits during the day but fall into the 60s at night. While in an extremely humid environment highs may be in the 90s and lows stay above 70, even close to 80. The latter is forecast this week and can be more taxing on the body when exposed to prolonged heat without being able to cool down.

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This the of this week is expected to be the hottest since July of 2013 based on the preliminary forecast but could trend hotter, especially if overnight lows stay closer to 80.

The all-time hottest period happened during the dust bowl of the 1930s and would have been more of a dry heat with relatively lower humidity. Not surprisingly the period included the hottest temperature ever recorded in South Bend 109°F.