Rainfall. Snowfall. Temperature. Simple. 

Why have a site devoted to past rainfall, snowfall, and temperature data?

Homeowners, lawyers, insurance companies, snow plow drivers, forensic meteorologists, and many other people are constantly searching for this information. It is often needed for disputes involving flood insurance and other weather-related damage claims.

The Weather Collector Home Page will get you this information in one click.

It is March 3rd, and I just did a search from April 27 to March 2nd. Why is my search coming up empty?

Most rainfall, snowfall, and temperature data takes several days to arrive. Often, searches using dates that are 0 to 5 days old will be empty.

It snowed significantly over my entire state during the afternoon of January 2nd. I just did a search for January 2nd and some stations have 8 inches and others have 0 inches. Why are some stations not recording the snowfall?

Some observing stations measure rainfall and snowfall totals very early in the morning, and other stations measure totals during the afternoon or evening.

Therefore, it is always a good idea to add one day after the snow (or rain) event has ended. So for the example above, search "From: January 2 To: January 3."

We had a storm in my state that was all snowfall and no rainfall. However, when I search on the storm dates for rainfall, a bunch of totals show up. Why?

Searching for rainfall totals at a station which recorded snowfall will give you the melted liquid amount of the snowfall.

Where does your data come from?

The data comes from the National Climactic Data Center (NCDC) as part of the Daily Global Historical Climatology Network.

According the NCDC website, "GHCN-Daily now contains records from over 75000 stations in 180 countries and territories." The Weather Collector uses United States data only and has access to about 40,000 stations. These stations come from many different sources, including official National Weather Service reports (often located at airports).

Some stations are part of the Community Collaborative Rain, Hail, and Snow Network (CoCoRaHS). The CoCoRaHS website describes this network as "a grassroots volunteer network of backyard weather observers of all ages and backgrounds working together to measure and map precipitation (rain, hail and snow) in their local communities."

This network is extremely important because it fills in a lot of the data gaps in areas where there is not an official observing station nearby. CoCoRaHS adds new stations to their network every year and, as a result, The Weather Collector adds these new stations to the maps! CoCoRaHS says "We are striving to have 30,000-40,000 active observers by the end of 2013."

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