Do all civil engineers have to work outside in all conditions?

If you decide to go into civil engineering, I highly recommend that you also become certified in structural engineering. A civil engineer may be able to build a road, but they can't build bridges. It will require additional study, but will be well worth it.
By the way, Civil engineers many times have to go outside too.

I think the best engineers are familiar with how projects are installed and operated. As an engineer you won't spend 8 hours in the rain as do the contractors, but civil engineers especially work with outdoor projects. If you really like creating civil projects I think you would appreciate seeing how they your designs are constructed.

Hello, Nathan:

Don't worry too much about working outside in the elements. After 40 years in the engineering consulting business, one of my complaints was that I usually did not get enough opportunity for outdoor work.The great majority of civil engineering (and most other eng. disciplines, as well) involves office work such as problem research, modeling, design, report writing, etc. Typically you will only spend a small portion of your time outside viewing the project site or coordinating with construction contractors. That said, young engineers often spend a year or two early in their career as inspectors at construction sites. This is time well spent as this experience will often be very useful later in your career in the Office.

Pete Sturtevant, PE