I'm about an hour north of Denver. Up until about 3-5 days ago we were in the 70s/80s for highs and 40s/50s for lows but the past few days have been rainy and cool (60s high, 30s low). The temps look to be staying in that area on the forecast. This rain down here has brought snow to the mountains so keep that in mind for any hiking you plan on doing. We haven't seen a frost down here yet but that'll probably change before the end of the month. The sun is setting by around 6pm.
The drive to Rocky Mountain National Park is worth it. Lots of hiking opportunity there too. Estes park, the town just outside of the park is also worth visiting. Pikes Peak is in the opposite direction but is also worth a visit. You can drive up to the 14k+ft peak as long is weather is OK.
If you give me more of an idea of what kind of hike you want to do (amount of mileage, elevation gain, whether you want to encounter snow or not, etc) I can offer up some suggestions but I've only lived here a year and a half so I'm not an expert.
If you are a beer guy, there are tons of microbreweries in and around Denver to try.