Greatest difference in Temperature on average from 2 places that are close together

[BBQ King]

Sydney during hot days can have a big difference between the coast and just inland. The coastal stations are often under a seabreeze and can be more than 5C cooler than somewhere 10km inland. I've seen differences up to 15C between the coastal suburbs and the inland western suburbs.

[Caleb Yeung]

Yakutat, Alaska and Whitehorse, Yukon.

[Walshie79]

Fort William and Ben Nevis summit. Massive difference for only 1300m, a height difference that goes unnoticed in many parts of the world. Coming down from the summit towards a sunny 15C Fort William I had to warn several foreign tourists going up in shorts "It's snowing up there".

[AdriannaSmiling]

San Francisco! In summer, the immediate coast can be 55 (with fog and wind) while a few miles inland can exceed 80 (sun and no wind).

[Adi from the Brunswicks]

Originally Posted by AdriannaSmiling

San Francisco! In summer, the immediate coast can be 55 (with fog and wind) while a few miles inland can exceed 80 (sun and no wind).

Same choice. The Bay area temperature change is insane.