A heat wave affects parts of the United States, first in the Midwest and then moving eastward, prompting officials to cancel or delay outdoor plans. Multiple outlets report that summer camps and other outdoor activities scheduled for Monday are stopped or postponed as temperatures remain dangerously high. In communities hit by the hottest conditions, local authorities open cooling centers and encourage residents to avoid strenuous activity, stay hydrated, and take precautions against heat-related illness. The reports also note that the East is preparing for worsening conditions as the heat shifts geographically. The overall response includes public guidance and access to air-conditioned or cooled spaces for people who need relief. While the specific jurisdictions vary by source, they align on the main pattern: high temperatures drive cancellations and delays for outdoor events in the Midwest, cooling centers are made available for safety, and attention turns to areas further east that expect similar heat in the coming days.