A chemtrail is a term used by many observers to describe the persistent white trails left behind by aircraft in the sky. While officially classified as condensation trails (contrails) formed when hot jet exhaust meets cold atmospheric air, a growing community of concerned citizens questions whether all trails can be explained this simply. ChemTracker lets you investigate for yourself by showing you exactly which aircraft are leaving trails, at what altitude, and under what atmospheric conditions — so you can draw your own conclusions based on real data.

How does ChemTracker work?

ChemTracker combines real-time ADS-B flight data with atmospheric science to show you every aircraft in your area. It uses your location, live weather data including humidity and temperature at cruising altitude, and the known science of contrail formation to predict which planes are likely producing visible trails. You can point your phone at the sky and see overlaid flight information in real time.

Can I track chemtrails in real-time?

Yes. ChemTracker provides real-time tracking of all aircraft in your vicinity and highlights which ones are currently producing visible trails. Using live ADS-B transponder data and atmospheric readings, the app updates continuously so you can monitor exactly what is happening in the sky above your location at any moment. You can also set up alerts to be notified when trail-producing aircraft enter your area.

What is the difference between a chemtrail and a contrail?

A contrail (condensation trail) is the official explanation for the white lines left by aircraft — formed when water vapor in jet exhaust freezes in cold, humid air at high altitudes. The term chemtrail is used by researchers and observers who believe some trails may contain additional substances beyond normal water vapor, noting that some trails persist and spread for hours while others disappear quickly. ChemTracker helps you study these differences by showing atmospheric conditions, aircraft identity, altitude, and trail persistence predictions for every flight overhead.

Chemtrails at Porto Francisco Sá Carneiro Airport (OPO)

Porto, Portugal · 41.24°N, 8.68°W · Last updated: Mon, 20 Apr 2026 07:23:36 GMT

Current Contrail Conditions

High Likelihood6/8 levels favorable

6 of 8 atmospheric pressure levels currently show conditions favorable for contrail formation.

Solar visibility: Excellent · Sun elevation: 16.9°

Atmospheric Conditions by Pressure Level

ChemTracker monitors 8 pressure levels above Porto Francisco Sá Carneiro Airport. Contrails form when temperature is below the Schmidt-Appleman threshold and relative humidity with respect to ice (RH-ice) exceeds 70%.

Pressure	Altitude	Temp (°C)	RH-water (%)	RH-ice (%)	Contrail
150 hPa	44,327 ft	-59	3	5	Unlikely
200 hPa	38,637 ft	-64	48	86	Likely
225 hPa	36,216 ft	-61.5	99	175	Likely
250 hPa	34,004 ft	-56.5	60	102	Likely
275 hPa	31,965 ft	-52	80	131	Likely
300 hPa	30,070 ft	-47	52	82	Likely
350 hPa	26,636 ft	-38.1	89	129	Likely
400 hPa	23,578 ft	-29.9	42	56	Unlikely

Solar Visibility Over Porto Francisco Sá Carneiro Airport

Visibility RatingExcellent

Sun Elevation16.9°

Visibility Factor96%

Solar visibility determines how well contrails can be observed from the ground. Higher sun elevation means better backlit visibility of trail formation above Porto Francisco Sá Carneiro Airport.

Frequently Asked Questions

Are there chemtrails at Porto Francisco Sá Carneiro Airport today?

ChemTracker monitors real-time atmospheric conditions above Porto Francisco Sá Carneiro Airport (OPO) to predict contrail formation. Currently, 6 of 8 pressure levels show conditions favorable for contrail formation — indicating high likelihood of persistent trails above this airport.

Why do planes at Porto Francisco Sá Carneiro Airport leave trails?

Aircraft departing or overflying Porto Francisco Sá Carneiro Airport (OPO) produce contrails when hot, humid jet exhaust mixes with cold ambient air at cruising altitude. This forms ice crystals that become visible as white trails. Contrails persist when the surrounding air is supersaturated with respect to ice (RH-ice above 100%), which can cause them to spread into cirrus-like haze lasting hours.

How does ChemTracker monitor aircraft at Porto Francisco Sá Carneiro Airport?

ChemTracker uses live ADS-B transponder data to track every aircraft in the airspace around Porto Francisco Sá Carneiro Airport (OPO) in real time. Each aircraft's altitude is cross-referenced against atmospheric data from Open-Meteo at 8 pressure levels. The app shows flight numbers, current altitudes, and whether atmospheric conditions at each level are favorable for contrail formation.

What atmospheric conditions cause contrails at Porto Francisco Sá Carneiro Airport?

Contrails form above Porto when air temperature drops below approximately −40°C at cruising altitude (typically 8,000–12,000 metres). The Schmidt-Appleman criterion calculates the precise threshold based on ambient pressure, relative humidity, and engine efficiency. When relative humidity with respect to ice exceeds 100%, contrails persist and spread. ChemTracker checks all 8 pressure levels above Porto Francisco Sá Carneiro Airport for these conditions every 30 minutes.

Nearby Airports & Related Pages

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Contrails Over PortoView contrail conditions above the nearest tracked city All Monitored AirportsView contrail conditions at airports worldwide Chemtrails LiveReal-time trail activity worldwide Contrail ForecastPredicted formation conditions for today and tomorrow

Track Aircraft at Porto Francisco Sá Carneiro Airport in Real Time

See every aircraft above Porto with its altitude, flight number, and whether atmospheric conditions at that pressure level are favorable for trail formation.

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