I am looking for data that will provide average monthly temperatures by zip codes in the US. I require only a year or two worth of historical data, as I am only looking for general trends.
Wunderground used to provide summaries like this through their API, but they no longer provide free api keys.
Other APIs provide historical data per day, which I can aggregate for monthly averages. However, this would quickly hit the API limits. Please let me know if there is a data dump, or API I could hit that may have this information.