Conditions.Site
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For Forensic Meteorologists & Weather Expert Witnesses

ERA5, NOAA station records, and personal weather stations: reconciled in one cited pass

Conditions.Site pulls historical weather for a single location and past date from multiple independent public sources, cross-checks them, and lays every value out in a per-source comparison table. The sourcing and QC work is done for you.

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Building a weather reconstruction means pulling ERA5 reanalysis, NOAA/NWS station records, and any nearby personal weather stations, then reconciling the numbers by hand and documenting where each one came from. Conditions.Site does that gathering and cross-checking in a single pass. You enter an address or GPS coordinates and a past date and time to the minute, and you get a clear, cited report of temperature, wind, precipitation, cloud cover, humidity, visibility, and pressure. Every value is traced to the source it came from.

The problem

Where the usual sources come up short when you need to establish what the conditions were.

Gathering sources eats the day

ERA5 lives in one portal, NOAA Local Climatological Data in another, and personal weather stations somewhere else. Pulling them all for one location and one past date, then aligning the timestamps to local time, is slow manual work before any analysis starts.

Reconciling disagreements by hand

Station records, reanalysis, and nearby personal stations rarely agree exactly. Deciding which value to cite, and defending that choice, means laying them side by side yourself, one variable at a time.

Sourcing has to be airtight

A weather opinion is only as strong as its provenance. When every figure needs to trace back to a named public source, keeping that chain organized across dozens of values is tedious and easy to get wrong.

Local time and timestamp alignment

Sources report in UTC, station-local time, or their own conventions. Getting an hourly picture in the location's own local time, for the exact minute in question, takes careful conversion every time.

How it's used

Reconstructing wind for a fallen-tree or structure claim

Pull hourly wind speed, direction, and gusts for the address and date from ERA5, the nearest NWS station, and any personal weather stations in range, then compare them side by side to characterize what the wind was doing at that hour.

Documenting precipitation and surface conditions

Assemble temperature, precipitation, humidity, and cloud cover from independent sources for a specific past date and time to support an opinion about ground or road conditions at the scene.

Locating the nearest records to an address

Enter the exact address or coordinates and let the report surface the relevant station data for that spot, with per-station detail, rather than defaulting to a distant airport reading.

Producing a cited exhibit for a report

Generate a paginated PDF with a one-page summary, a per-source comparison table, an hourly table, and per-station detail. The result is a clean, well-sourced attachment for your written analysis.

What you get

Every value is cross-checked across independent public sources and cited back to its origin.

Multiple independent sources, cross-checked

Historical weather reconciled across ERA5 reanalysis (via Open-Meteo), NOAA/NWS station records (Local Climatological Data), and personal weather stations: temperature, wind speed, direction and gusts, precipitation, cloud cover, humidity, visibility, and pressure. Sources are compared against each other so you see where they agree and where they diverge.

Every value cited to its origin

Each number in the report carries the source it came from. Nothing is presented without provenance, so the sourcing chain behind your reconstruction is documented as you go rather than reassembled afterward.

Per-source comparison table

A technical table lines up each variable across ERA5, station records, and personal weather stations for the date and time in question. It is the reconciliation view, built for you, ready to reason from.

Sun and moon position, terrain-aware

Altitude, azimuth, rise and set, solar noon, twilight, and moon phase for the exact place and past moment. Local terrain and nearby buildings are factored into whether the sun or moon was above the visible horizon at the site.

How it works

  1. Enter the place and the exact past moment

    Search an address or intersection, or drop in GPS coordinates. Set the date and time to the minute, in the location's own local time.

  2. Sources are gathered and cross-checked

    Conditions.Site pulls ERA5 reanalysis, NOAA/NWS station records, and nearby personal weather stations for that spot and time, aligns them, and compares them against each other.

  3. Review and export the cited report

    Read the one-page summary, the per-source comparison table, the hourly table, and per-station detail, then export a clean paginated PDF with every value traceable to its origin.

Frequently asked questions

How do I reconcile NOAA station data with reanalysis for a forensic report?
Conditions.Site pulls both NOAA/NWS station records (Local Climatological Data) and ERA5 reanalysis via Open-Meteo for your location and past date, plus any nearby personal weather stations, and lays them out in a per-source comparison table. Each variable is shown across sources so you can see agreement and divergence and cite the value you rely on. The reconciliation view is built for you; the interpretation and opinion remain yours.
Can I get hourly historical weather from multiple sources for one location?
Yes. Enter an address or coordinates and a past date, and the report includes an hourly table drawn from the available independent sources, in the location's local time. It covers temperature, wind speed, direction and gusts, precipitation, cloud cover, humidity, visibility, and pressure.
Does the report include a cited per-source comparison table for a specific date?
Yes. The PDF includes a technical per-source comparison table that lines up each variable across ERA5, NOAA/NWS station records, and personal weather stations for the date and time you entered, with per-station detail. Every number is cited to the source it came from.
Where does the historical wind speed and gust data come from?
Wind speed, direction, and gusts are assembled from independent public sources: ERA5 reanalysis and NOAA/NWS station records, plus personal weather stations when available near the location. Each source's values are shown separately so you can compare them rather than relying on a single reading.
How does it find the nearest weather station records for an address on a past date?
Give it the address or GPS coordinates and the report surfaces the relevant station records for that location, with per-station detail so you can see which stations contributed and how their readings compare. That keeps the analysis tied to the site rather than to a distant default station.
Are these reports guaranteed accurate or admissible in court?
No. The reports are modeled estimates assembled from cited public data for informational use. They are well-sourced and cross-checked, and designed so every value traces back to a named public source. They are not a guarantee of the actual conditions, and they make no claim about legal admissibility. The professional judgment stays with you.

Do the sourcing once, cited from the start

Enter a place and a past moment and get ERA5, NOAA/NWS station records, and personal weather station data reconciled in one pass. Everything is cross-checked, laid out in a per-source table, and exportable as a clean cited PDF. Start free with 5 full reports a month, or go unlimited for $19.99 a year.

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Related uses

Accident Reconstruction → Insurance Claims → Storm-Damage Contractors →

Conditions.Site reports are modeled estimates assembled from cited public data sources for informational use; they are not a guarantee of actual conditions.