A separate rain cover can be hard to fit well if the bag wasn’t designed with one in mind. In general, if weather protection is important, it’s often better to choose a similar backpack that already includes a dedicated rain cover.

That said, some bags offer decent light-rain resistance even without a full cover. One user noted that older versions of this style had zipper flaps that were quite effective against normal rain, with a full rain cover mainly being useful in heavy downpours.

Alternatives mentioned were:

• a Tamrac laptop backpack with an included rain cover and tripod straps
• the Kata Bumblebee range, which was recommended as a strong option for long-term use

So if you expect frequent rain, the safest choice is to look for a comparable camera backpack with an included rain cover rather than relying on a generic add-on.