If I read this correctly, you live in the Northwest (Seattle) and have AWD. Is it correct to say rain is a common day to day experience in Seattle at this time of the year? If this is true, then it might be possible that your vehicle is going into and out of AWD on a regular basis (due to rain induced slick pavement). This can cause a hit on your milage. I have an AWD vehicle and have experienced a hit in fuel milage during rain-rain storms and slick roads. I image this will also be true during snow covered roadways.

The other item that caught my attention was your short daily commute--2 miles one way to work and 5 miles at lunch time. Our experienced posters have commented previously that short commutes such as this will not allow your hybrid to reach its potential fuel efficiency. I also have a short 4-5 mile commute and can not match the figures posted by many others on this site due to this. On the weekends, my milage improves significantly.

2005 AWD Escape Hybrid
Best Interstate tank trip MPG 39.02 (scangauge II) for 402 miles on I-70, 10.3 gallons used over mostly flat terrain.

Best Interstate tank trip E30 MPG 34.6 for 271 miles along I-80 in Indiana and Ohio.

Best multiple road tank trip E30 MPG 36.2 for 202 miles in Southwestern Pa.