My 4 year old daughter developed a fever on Monday, it would range from 100 - 102. She had also had a cold for 2 weeks and been coughing for 2 days so I was concerned it was pnumonia so I took her in Tuesday (in horrible weather). the Dr said she had some wheezing (a very tiny bit) in her lungs and they had us get her a nebulizer (which was $299 and I know our insurance wont pay for because of deductable), the med to put in it, and instructions to use it 3x a day. Wed night she even got up to 103 when the Ibroprofin wore off at 4am. We had a follow up appointment yesterday, lungs were clear as a bell, they took blood (another $ in lab work) and everything looked fine. DR said it is a virual infection and is common to cause fevers for 7-10 days, and to call if she is still having a fever on Monday.
I blame winter in MN.
If your DR is open sat/sun I would think it is fine to wait. The risk of the icy roads might be worse than the risk of waiting, you can always go to the ER if the temp gets to 104 or 105 (not sure what the rule is with a 2 year old).