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Mars Phoenix Lander Weather Reports and Backyard Stations

NASA's 2008 Phoenix Mars Lander MET compared with a backyard weather station: pressure, dust, and temperature range. Historical, not live Mars weather.

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A backyard personal weather station (PWS) and a landed spacecraft meteorological package are the same kind of instrument story: temperature, pressure, wind, and atmospheric particles, each tied to a place and a clock. They are not the same climate. NASA’s Phoenix Mars Lander carried a Meteorological Station (MET) that recorded polar-Martian weather in 2008. That record is historical. This page is not live Mars weather, not an Earth forecast, and not a claim that a Mesa, Arizona hobby station measured another planet.

The historical TNET Weather URL /mars.php tried to display Phoenix weather reports on the main station site. Recovered captures show a failed remote fetch to a Canadian Space Agency Phoenix weather page and a “No Data found” result. Those fragments identify the old function. They are not a dataset. This article replaces that broken pull with an educational comparison: what Phoenix MET measured, how that differs from a backyard PWS, and why pressure, dust, and temperature range are the honest axes.

Spell the spacecraft Phoenix. The historical title used a typo. The lander did not.

Historical context

Phoenix launched on 4 August 2007 and landed on 25 May 2008. NASA’s Jet Propulsion Laboratory describes the mission as a polar lander that dug into icy high-latitude ground, confirmed subsurface water ice, and ended communications in November 2008, about six months after landing, when solar panels ceased operating in the dark Martian winter (JPL Phoenix mission, last checked 13 August 2026).

The Canadian Space Agency provided the MET: temperature and pressure sensors plus a lidar for dust, clouds, and fog in the lower atmosphere (CSA Phoenix, last checked 13 August 2026). JPL notes a wind telltale from collaborators at Aarhus, Denmark, and other international contributions including the Finnish Meteorological Institute (JPL, 29 May 2008).

Hobby weather sites of that period sometimes mirrored “Mars weather” widgets the way they mirrored NOAA forecasts: a remote HTML scrape next to the local thermometer. /mars.php was that novelty. Scraping a third-party page is not an observation. When the remote host would not resolve, the page correctly had no data. TNET does not resume that scrape. Official Phoenix MET products live in NASA’s planetary data archives, not in a restored PHP fopen.

What Phoenix MET measured

Treat the following as documented mission facts, not as a global Martian climatology.

Temperature. MET used thermocouples on a short mast at three heights above the lander deck, so the package could see a near-surface vertical gradient rather than a single shelter reading. A PWS typically publishes one outdoor air temperature from a shielded sensor at about two meters. Same quantity name, different geometry.

Pressure. A deck-mounted barometer recorded atmospheric pressure at the landing site. Archived MET pressure/temperature products use SI units (kelvin, pascals) in the NASA Planetary Data System documentation. A Mesa PWS of the same era more often published inches of mercury, sometimes with a millibar equivalent. Comparing the two without converting units is a category error.

Dust, clouds, fog. The lidar emitted laser pulses and timed returns from particles aloft. JPL reported dust to about 3.5 kilometers on an early mission day, and later a sol 99 (3 September 2008) cloud profile with ice crystals falling—water-based snow that did not reach the surface in that published interpretation (JPL PIA11200; JPL, 29 May 2008). A backyard station almost never has a lidar. Do not treat a webcam “haze” note as a Phoenix profile.

Wind. The telltale was imaged so speed and direction could be inferred. A PWS cup-and-vane or sonic anemometer is a different instrument. Both still need a unit and an averaging interval.

Time. Phoenix used sols (Martian solar days) as well as Earth UTC. A PWS uses a terrestrial timezone. A “daily” high on Mars is not a Mesa calendar day. Any comparison table must show both clocks.

JPL’s second-day weather report for the landing site is a dated historical observation: sunny with moderate dust, high −30 °C (−22 °F), low −80 °C (−112 °F) (JPL, 29 May 2008). That pair is a documented range for that site on that sol. It is not a Mars-wide climate average, not a current reading, and not a number to paste onto a Mesa dashboard.

Three comparison axes that stay honest

Pressure

A PWS is built to resolve terrestrial surface pressure in tenths of an inch of mercury or in hectopascals. Phoenix measured a CO2-dominated polar atmosphere at lander-deck height in a much lower-pressure regime. The same word “barometer” does not imply the same dynamic range, unit, or weather story. Convert to one SI unit, name the sensor height, and keep the clocks. Do not average the two series. Copying a PWS “falling fast” icon onto a Mars widget would be theater.

Dust

On Earth a PWS might record visibility, a webcam, or a low-cost particle count. None of those is a vertical backscatter profile. Phoenix lidar was built to see how dust and ice were layered above the deck—information that changes radiative heating, solar-panel output, and cloud processes.

The comparison that helps a station owner: atmospheric particles are a first-class weather variable, not a sky comment. If your site talks about haze, smoke, or monsoon dust, say which instrument produced the claim. If you have no instrument, do not invent a lidar-like number from a photograph.

Phoenix’s published snow-from-cloud result is a lidar interpretation with a date (sol 99 / 3 September 2008) and a qualifier (ice falling, water-based, not reaching the surface in that report). A backyard “it snowed” row is a precipitation gauge or a human note. Different sensors, different completeness tests.

Temperature range

A desert PWS can see large diurnal swings by terrestrial standards. Phoenix’s documented early-mission high and low at the landing site span tens of degrees Celsius below freezing. The lesson is range and siting, not a contest.

A mast with three thermocouples exists because the lowest meter can be strongly stratified. A single PWS probe in a Stevenson-style shield samples the same idea differently: height matters. Roof vents, pavement, and lander-deck heating are all siting biases. Station configuration is how a backyard operator records that geometry; Phoenix MET documentation is how a mission records it. Neither dataset is usable if you strip the height and the clock.

Do not invent additional Martian climate statistics for this page. If a number is not in a cited NASA/JPL or CSA source above, omit it.

What a hobby “Mars weather” page must not do

  • Do not scrape and relabel. A remote HTML page is not a MET archive. When fopen fails, the honest output is “no data,” which is what the recovered TNET page already showed.
  • Do not mix clocks. Sol 2 is not 27 May on a Mesa logger without a stated conversion.
  • Do not mix units. Pascals, hectopascals, and inches of mercury are not interchangeable labels.
  • Do not present Phoenix as current. The lander stopped communicating in November 2008. Later Mars weather comes from other missions and models, each with its own provenance.
  • Do not imply NASA endorsement. TNET is independent. Citing JPL is attribution, not affiliation.
  • Do not drop completeness. A Mars widget that shows a temperature with no site, no sol, and no unit fails the same test as a current-conditions table that omits MST.

A complete comparison sentence looks like a complete observation sentence: identity, time, variable, value, unit, and which planet’s surface produced it.

Practical checklist

  1. Name Phoenix correctly. Treat 2008 MET output as historical.
  2. Compare pressure, particles, and temperature range as instrument classes, not as a single “Mars vs Arizona” score.
  3. Cite NASA/JPL or CSA for lander facts. Do not invent global Martian averages.
  4. Keep PWS numbers in their own rows with their own timezone and siting notes.
  5. Label lidar, webcam, and visibility as different particle methods.
  6. Do not restore a live scrape of a third-party Mars weather URL.
  7. Send readers who need local terrestrial conditions to official NWS products, not to this educational page.

Modern relevance

Planetary MET packages and backyard stations both force a provenance question: which sensor, which height, which clock, which unit. That is the same discipline TNET applies when public weather records are used as research evidence. This comparison is educational. It does not feed a Connection Outlook and it does not describe proprietary forecast assembly.

How source identity, units, and quality control are discussed is data sources, quality controls, and methodology. Related station pages sit on the weather-station hub.

Sources