...My steel-framed touring bike weighs 33 pounds naked, add front and rear rack and four panniers; +20 pounds, add 40lbs of clothes, camping gear, bike tools, tubes, spare tire, laptop and water and you're looking at 90lbs give or take...
...left town...about 1130...
Couple suggestions:
Lighten the load.
Leave earlier, before the heat of the day sets in.