xerothermic

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Both dry and hot.
• adjective Adapted to or flourishing in an environment that is both dry and hot.

from The Century Dictionary.

• Dry and hot; arid and warm: describing a climatic condition similar to that of the steppes of southern Russia.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Both hot and dry
• adjective of an organism That flourishes in hot, dry conditions