The presence of oceans or other large bodies of water (the great lakes) usually helps regulate the temperature and it weeds out extremes. Both the hottest and the coldest temperatures are usually measured in the middle of the continental landmasses.
The Ice Harbour Dam is inland actually, amongst the mountains. It's a lot drier in eastern Washington, and the climate is different from the coastal rainforest.
South Dakota is weird...check out Spearfish, South Dakota. Here is an excerpt from Wikipedia:
Spearfish holds the world record for the fastest recorded temperature change. On January 22, 1943 at about 7:30 a.m. MST, the temperature in Spearfish was −4°F (−20°C). The Chinook wind picked up speed rapidly, and two minutes later (7:32 a.m.) the temperature was +45 °F (+7 °C) above zero. The 49 °F or 27 °C rise in two minutes set a world record that still holds. By 9:00 a.m., the temperature had risen to 54 °F (12 °C). Suddenly, the chinook died down and the temperature tumbled back to −4 °F or −20 °C. The 58 °F or 32.2 °C drop took only 27 minutes. The sudden change in temperatures caused glass windows to crack and windshields to instantly frost over.
I'd never heard of the Chinook until I read Laura Ingalls Wilder's book _The Long Winter_. They were buried in snow one day, the Chinook began blowing in the night, and by next day they were buried in mud.
Heck yeah! As I and from South Dakota I can say that the temperatures do very a lot, as South Dakota is on the states with the highest and lowest recorded temperatures quizzes
"The previously reported record of -69 degrees F set at Peter's Sink on Feb 1, 1985 is widely considered an accurate observation, but no information concerning the observation or the station could be identified, and the value is heavily affected by the local terrain. The -50 degrees F at Strawberry Tunnel is the coldest temperature observation that can be verified from publicly available observations at established observation stations in Utah."
Spearfish holds the world record for the fastest recorded temperature change. On January 22, 1943 at about 7:30 a.m. MST, the temperature in Spearfish was −4°F (−20°C). The Chinook wind picked up speed rapidly, and two minutes later (7:32 a.m.) the temperature was +45 °F (+7 °C) above zero. The 49 °F or 27 °C rise in two minutes set a world record that still holds. By 9:00 a.m., the temperature had risen to 54 °F (12 °C). Suddenly, the chinook died down and the temperature tumbled back to −4 °F or −20 °C. The 58 °F or 32.2 °C drop took only 27 minutes. The sudden change in temperatures caused glass windows to crack and windshields to instantly frost over.
See: https://en.wikipedia.org/wiki/Peter_Sinks
"The previously reported record of -69 degrees F set at Peter's Sink on Feb 1, 1985 is widely considered an accurate observation, but no information concerning the observation or the station could be identified, and the value is heavily affected by the local terrain. The -50 degrees F at Strawberry Tunnel is the coldest temperature observation that can be verified from publicly available observations at established observation stations in Utah."