During the spring window on Boulder Creek there can be some very good fishing, but it can be fickle. The fishing can shut down or turn on at any moment during the course of the day. Even the slightest fluctuation in water temperature can affect the trout. The fishing will improve noticeably for every increase in temperature from 44 degrees up to 47 degrees. On sunny days the water temperature will steadily increase and so will the quality of fishing. You can use this knowledge to plan the time you begin your day on the creek, or where on the creek you choose to fish. If the fishing is slow, take a temp and if it is still in the lower forties you can relocate farther downstream where the water may be a few degrees warmer. This can be the case if you follow the creek downstream until it levels out, or a diversion canal removes some of the water.
One year the spring window opened a week late, because the March flows were high so the temperatures didn’t rise as quickly as they usually do. The fishing was crazy good the entire first week of April…then we had two days of freezing rain followed by a day of snow. The water temperature dropped from 45 degrees down to 32 degrees and the trout tried to bury themselves under the gravel! But one hot, sunny day later the creek was all the way up to 49 degrees. The unfortunate part of this antidote is that by the time all the trout recovered enough to return the fishing to its former glory the pre-runoff began (the steady increase that precedes the spring runoff) and the fishing didn’t get that good again for another three months.