In bright sunshine
At the best of times, your opening will be spoiled by glorious sunshine, pleasant temperatures and clear skies. These conditions can be both ideal and bad for hooking fish. If the river water tends to be very cold, in rivers with high flows or at altitude, bright sunshine can heat up the water quickly in shallow areas. Invertebrate activity can then be triggered, giving trout the urge to bask in the sun and intercept any small fish or insects passing by.
On the other hand, in rivers that are already relatively warm, clear weather will make approaches much more difficult and you'll need to fish more discreetly. Walking gently along the water's edge, not squeaking stones or reducing the diameter of leaders are good ways to increase your chances of success.
On an overcast day
Overcast, when the sky is laden with thick, gray clouds, is another possibility for weather conditions usually encountered during trout openings. Overcast skies are often synonymous with atmospheric depression, which can get the fish active, but if temperatures are already low, this can make the fish lethargic. Educated fish will be easier to deceive, however, as the quality of their vision will be reduced by the lack of light.
This may give you a better chance of catching a big fish, even if you don't use ultra-discreet equipment. Approaching the river's edge is also much easier, although you still need to be as discreet as possible. On an overcast day, it's not uncommon to be surprised by a fish that was stationed at the edge, which you wouldn't have seen when approaching, even with quality polarized glasses.
In the rain and wind
When you think of the worst conditions for an angler, wind and rain are undoubtedly tied for number 1. However, don't forget that fish aren't afraid of getting wet in the rain and their fingers aren't cold in the wind. The number of anglers on the banks of a river on an opening day when the weather is miserable will be much lower, allowing the most motivated among you to get to the good spots first.
Fishing will obviously not be easy, but the results can be very good, especially in areas that are usually very busy during the opening season.
