canicular

• The point, however, was that they had changed places; Maggie had from her window, seen her stepmother leave the house -- at so unlikely an hour, three o'clock of a canicular August, for a ramble in garden or grove -- and had thereupon felt her impulse determined with the same sharpness that had made the spring of her companion's three weeks before. —  The Golden Bowl — Volume 2
• And now in the torrid heat of summer, the canicular days being at hand, the furnaces in the glass-house of the said Angelo have been extinguished. —  Marietta A Maid of Venice
• Zorzi, called the Ballarin, although he has removed from the furnace of the said Angelo the glass which was to be kept hot, does insolently and defiantly refuse to put out the fire in the said furnace, and forces the boys to make the fire all night, to the great injury of their health, because the canicular days are approaching. —  Marietta A Maid of Venice
• That the 'Religio Medici' was the work of a gentleman before his thirtieth year, not a recluse nor trained in a cloister, but active in a calling which keeps closest touch with the passions and frailties of humanity, seems to justify his assertion, "I have shaken hands with delight [_sc. _ by way of parting] in my warm blood and canicular days." —  Library of the World's Best Literature, Ancient and Modern — Volume 6
• During the canicular heat of August, many of the town's residents venture to the local swimming hole in search of a way to stay cool. —  Merriam-Webster's Word of the Day

Allen's Synonyms and Antonyms