SSOD Guide – USA, Canada & Global

Use NOAA SSOD to find observed daily weather data worldwide, compare UTC-day summaries responsibly, check data completeness, and export station records to Excel.
Author

Climate Explorer Team

Modified

August 3, 2026

Open the SSOD Explorer

SSOD Explorer map view with blue markers for weather stations worldwide

SSOD Explorer map showing global weather stations

Quick start

  1. Open the explorer, choose one or more countries, and set the date window needed for your question.
  2. Select a map marker or double-click a station-table row.
  3. Compare daily summaries, temperatures, and precipitation in Dashboard.
  4. Check the station identifier, UTC-day basis and missing values before interpreting the chart.
  5. Export the selected station record to an Excel (.xlsx) file.

1. Introduction

The SSOD Explorer is an independent visualization of NOAA’s Synoptic Summary of the Day (SSODv2) data. It provides observed daily weather records for stations in the United States, Canada, and countries worldwide. SSOD aggregates data by the UTC calendar day (00:00 to 23:59 UTC), rather than local climatological days, enabling consistent cross-country comparisons.

Climate Explorer is not affiliated with NOAA. The NOAA NCEI SSODv2 product page and technical documentation are authoritative for the source data and field definitions.

4. Parameter Reference

SSOD provides daily summaries. It does not expose conventional string quality flags for the displayed daily variables; it includes measurement-count fields instead. Climate Explorer masks values outside broad physical bounds and applies simple relational checks, such as maximum temperature not being lower than minimum temperature. These application-level checks are screening safeguards, not a replacement for source-provider quality control.

Displayed variable Definition Unit
Date SSOD summary date YYYY-MM-DD (00:00–23:59 UTC)
Mean temperature Mean of the contributing reports °C
Maximum temperature Highest reported temperature represented in the SSOD summary °C
Minimum temperature Lowest reported temperature represented in the SSOD summary °C
Precipitation Precipitation amount reported for the synoptic day mm
Mean wind speed Mean of the contributing wind-speed reports m/s
Maximum wind gust Highest reported gust represented in the summary m/s
Mean sea-level pressure Mean pressure reduced to sea level hPa

5. Worked example: Central Park, 1–4 July 2026

This example shows how to examine a short event while keeping the time basis and verification source explicit.

  1. Open the preselected Central Park route.
  2. Confirm station USW00094728 in the Dashboard header.
  3. In Plots, inspect maximum temperature for 1–4 July 2026; then open Data to check the corresponding rows.
  4. Record the values as UTC-day summaries. Do not silently relabel them as local-calendar daily maxima.
  5. Compare the key day with an official local product before describing a record. The evidence path and calculation notes are shown in the Central Park heatwave analysis.

The example demonstrates why a professional interpretation includes both the exploratory result and an independent verification step.

6. Methodology for station comparisons

Define a comparable observation

Write down the station ID, variable, unit, start and end dates, and the UTC-day convention. When comparing two stations, use the same variable and date window. A difference between stations can describe those observation points; it should not automatically be generalized to two cities, regions or countries.

Check completeness

Use the Data table to identify missing dates and missing variables. A blank precipitation value is unavailable data, not a dry day. Measurement counts, when present in the exported source fields, provide context on how many reports contributed to a summary but do not certify that the daily extreme or total is complete.

Choose the appropriate source for the claim

NOAA explains that SSOD is valuable because every station uses the same synoptic day and data arrive with a relatively short delay. NOAA also cautions that precipitation may be underreported in synoptic messages and that reported maxima and minima may not equal the true daily extremes. Use SSOD for consistent screening and event chronology; use national-service daily summaries or GHCNd when the most accurate local daily rainfall or temperature extreme is required.

Add a baseline only after matching the metadata

To place an event in climatological context, compare it with the same variable and calendar period at the same observing site. The WMO Normals Explorer provides 1991–2020 station normals, while The Limits of WMO Normals in a Warming Climate explains when such a baseline is—and is not—appropriate.

7. Troubleshooting and quality checks

  • Missing Quality Flags: SSOD does not expose conventional string QC flags for the daily summaries. Treat the explorer’s physical and relational checks as screening only.
  • UTC Alignment: Remember that a “day” in this dataset runs from 00:00 to 23:59 UTC, which may straddle two local days depending on your timezone.
  • Missing Values: Do not replace blank cells with zero unless the upstream field definition explicitly supports that treatment.
  • Different Station Periods: A station can appear in the catalog but lack a requested variable or date. Check its full availability period in the station metadata.