What is the best and most accurate way to find out what the weather was on a certain day in the past?

Will this page do it for you? You can search by month and date; January 2015 should be the one that comes up.

In any case, I did a search for “daily weather January 2015 westchester county new york” and several choices came up.

I use NOAA for most of my weather info. Try past weather then click on your location and search by archived dates. That goes back for a couple of months. I haven’t tried to go further back than that.

Check with your local newspaper.

NOAA hosts weather information (temperature and precipitation at a bare minimum) for practically the entire world. Here’s how to use the tool that I use most often:

Go here: http://www.ncdc.noaa.gov/cdo-web/datasets

Click Daily Summaries, then Mapping Tool

This works kinda sorta like Google Maps. Wait for it to load (you’ll see little circles pop up on the map), then click and drag it to your region and zoom in using the bar on the side. It can be a bit slow to respond – be patient.

Once you have zoomed in enough to see weather stations in your region clearly, click the “Select by Rectangle” icon (in the left-hand box floating on your map. It looks like a dotted rectangle with a cursor on it). Your cursor becomes a crosshair. Click near your closest weather station and drag the rectangle to include as many stations as you wish – choose a few, because not every one will offer what you want. A new box will appear, listing those stations.

Check the boxes beside the stations you want data from, then click Get Selected Data. A new window will open, asking what file type you want your data in (pdf, comma-separated text file, or text file), and the date range. Click “Continue” at the bottom of the page.

On the next page, enter your email address, and a link to the file will be emailed to you within a few minutes.

If the mapping tool is driving you crazy, you can experiment with other tools in the first step. But this will pretty much give you access to all weather data ever recorded and shared with the US government.

Time travel.

This site looks like it’s really easy to use.