The quality, state, or degree of being droughty; the condition of having prolonged lack of rainfall or water; dryness.
From droughty (adjective) + -ness (abstract noun suffix). The suffix -ness turns the adjective describing dryness into a noun describing the abstract quality itself.
Droughtiness is how meteorologists and poets once described the creeping dread of a dry spell—not just one dry day, but the persistent, oppressive condition of prolonged thirst.
Complete word intelligence in one call. Free tier — 50 lookups/day.