I am happy to see the 8th month begin as we think about fishing on the Metolius. I think we need a weather break to make happen what I expect to happen and I don’t know when that will be? Last week they said by mid next week that the heat wave would be moderating, and now the newest forecast is for more of the same. 
Despite the hot, bright days, we’ve had some positive stuff happen this week. A good push of Bull Trout appears to have arrived and I know of some gorgeous fish being landed on big nasty streamers in the last few days. The Golden Stone action continues to be a strong player in the Headwaters to Gorge area. Look for Goldens in the Canyon and below Bridge 99 now as well. Also keep an eye on Salmonflies. Not a huge hatch of the big orange mama’s on the Met, but in August and early September you ought to have a Salmonfly at the ready on the your fly patch. 
Mayfly hatches have been more sparse than normal I think because of the heat. PMD’s are the star of the show in Summer, but don’t overlook Blue Wing Olives and in August we also look for Mahogany Duns (upper, middle and lower river) and Ameletus #14 olive (middle and lower river). My friend Chester and I were discussing the rusty spinner fall and both of us agree it is worth going in the early AM to fish spinners since the dusk spinner fall is not hitting on all cylinders like it ought to be. I have enjoyed early AM rusty spinners in the past, and if you have fished these low floating (hard to see) spinners at damn near dark, you are going to love seeing them as the light is increasing in the morning. And if you get there in the morning with no dry fly takes, bring your nymph box and change tactics. 
Any day now we are going to have an explosion of tiny yellowish/tan micro caddis in the middle and lower river. #20 yellow Iris Caddis and #20 Tan Elk Hair Caddis are my patterns of choice for these. The #16 Tan and Olive caddis will not only continue this month, they will get better. Remember to fish the pre-hatch emergence of caddis using a Pupa, especially during the later afternoon and evening times.