This is a great and scenic course that mostly runs along the river with a few miles through residential neighborhoods. There are parts of the course that are not shaded and the temperature can get quite high (mid 90s) so be prepared with sunscreen and carry water if race day temps look high. That said, the aid stations are fully stocked and the course is well supported. It is a great event and I would recommend it to anyone.
By NTL about 2015
The course is relatively flat and the volunteers were absolutely awesome. The race was run mostly well, but.... the high the day of the marathon was 92 degrees F (a scorcher for the NW that early in the season) and there was no ice on the course. The gummy bears were a melted mess, and the Ultima and water were lukewarm by the later miles. I passed by so many people who were passed out or near heat exhaustion. Only run this if you do well with heat and can do without the ice to cool you off. Also, aid stations 2+ miles apart, even in the last 10K felt like forever in the parts of the course with no shade. Be prepared to either be self sustaining, tough it out, or have someone on course helping you if you overheat easily.
Obviously, the temperature every year will be different, but with this course not trying to negative split if you are prone to heat exhaustion would be wise. If it's a hot day, the longer you are on blacktop with no shade, the worse for the wear you'll be. Waiting until later miles to rev up to full speed may mean that you are covering ground faster as the temperatures are rising.
By T about 2015
This is definitely a fast course, but early June in Spokane can be HOT. It was this year, and that cost me 10 minutes minimum in my time. Also the organizers didn't have ice, or anything old at the aid stations, just warm water or Ultima. The only way I'd do it again would be as a last minute registration after the forecast was out.