September is the month that hikers in western Oregon look forward to more than any month. Rainless days are almost guaranteed, mosquito levels drop off quickly and tourists thin out after Labor Day. This year there are a few qualifications to what is typically our best month for backpacking. Mosquito levels may be slow to disappear in the high country because there haven’t been enough freezing nights.

The unusually warm and dry weather has led to extremely high fire danger. This might be the year to try hiking like John Muir: no fires or stoves at all, just nuts and dried fruits. And, to be contemporary, corn chips, energy bars and cookies. It means traveling very light, as no pots, pans or kettles are needed.

Warm weather brings on flushes of toxic bacteria in lakes and slow moving rivers; erroneously called algae or bluegreen algae, they are actually photosynthetic bacteria called cyanobacteria. The really bad population explosions look like someone has poured turquoise-tinted white latex paint in the water. This stuff is not good to drink, wash or even swim in. Watch for state notifications.

Reptiles are at their time of most rapid growth. With body temperature controlled by the environment, high activity in warm weather allows fattening up for the cool winter months to follow. Two species of native snakes are different from most reptiles in that their eggs are incubated and hatched inside the mother’s bodies so that live young are born: rubber boas and garter snakes.