Hi resnyc,
Welcome to Apple Support Communities. We understand that you're having an issue with Siri providing the correct weather when using your HomePod. We'd like to help.
Which device are you connecting to your HomePod? If you ask Siri the weather on that device directly, what are the results? Which iOS is that device running? Head to Settings > General > About to find the exact number. If you're not running iOS 16.0.3 or iPadOS 15.7, updating the software can help:
Update your iPhone or iPad - Apple Support
Update your iPhone or iPad wirelessly
1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. Choose the software update that you want to install. You can choose to stay on iOS or iPadOS 15 and still get important security updates. Or you can choose the option to upgrade to iOS or iPadOS 16.

5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.
Hope that helps.
Cheers!