You may have created a customized Google home page. Try this address and when you find your customized page, you can make it your home page:

http://www.google.com/ig

How to set the home page | How to | Firefox Help

On the other hand, if your weather appeared in a toolbar, it's possible that the add-on is not yet compatible with Firefox 4. If you explore the following list, can you find a disabled weather add-on?

(If you have the orange Firefox button, tap the Alt key)

Tools > Add-ons > Extensions

Thank you so much for your answer. The weather did appear in a bar just above the bottom toolbar, but doesn't any longer. I did as you suggested and found the extension (thanks--I didn't know how to do that). It looks like it's active. I did find another extension that was disabled but this one called Forecastfox wasn't disabled. I don't know why the icons wouldn't show up. And I didn't think that was the name of the program, but it must have been. I'm not very computer literate, and the computer person at the shop where I bought the computer put that program on there for me. I may try to call him. In the meantime, I don't think I like Firefox 4.  :( It seems very different. I hope I can get used to it. I don't suppose there's a way to get back to the other Firefox version? But thanks very much for your help. I do appreciate it.

Sure, there is a way to reinstall Firefox 3.6. It will be maintained with security updates for a while. But first, check whether you can display your missing bar from the Toolbars menu:

(If you have the orange Firefox button, tap the Alt key)

View > Toolbars

If you don't see one specifically for the weather, make sure the Add-on Bar is displayed.

jscher2000, THANK YOU! Problem solved!! I went to View>Toolbars, and found that there was no check mark by the Add-on Bar! I checked it and there was my forecastfox bar! I don't know a lot of those seemingly simple steps to take when I have a problem, but today I learned something, and I thank you so much!