Using the live map

A radiosonde is a weather instrument carried by a balloon. This map follows them across the lower 48 states and Washington, DC. Balloon symbols show ascent; parachutes show descent. Gray symbols indicate older reports.

  1. Choose a flight. Tap a balloon on the map, or open Flights and choose one from the list. Each flight is identified by its instrument's serial number. The selected balloon gets a blue halo.
  2. Read its measurements. Open Details for altitude, temperature, flight charts, profiles and exports. Map closes that panel and keeps your selection.
  3. Review its path. Open Replay, press Play, or drag the slider. More contains speed and previous/next report. Go live or × returns to the latest position.

Flights, Details, Replay and Layers are labelled in the desktop header or phone navigation. Details and Replay become available when you choose a flight. On phones, drag a sheet handle to resize it. One detail/list/layers panel opens at a time; the small playback strip can remain visible with it.

Tools → Focus map hides the header, navigation and panels, keeping playback controls available if you opened them. Exit focus or Escape restores the controls. Native full screen is a separate option in Tools. Site links and ZIP forecast search are in Menu.

Clicking a map symbol preserves your view. The flight list or serial search centers on the latest position once. Fit track shows the received path. Follow keeps the selected sonde centered; dragging, zooming or choosing another flight releases it.

You can open Details while replaying to inspect the measurements at the displayed time. GPS altitude is relative to mean sea level, not local ground. Missing measurements stay blank. Clear selected flight removes the selection, trail and playback.

Solid green/purple paths are received ascent/descent positions. Dashed amber paths are uncertain forecasts. A signal lost label does not confirm a landing. Recent trails contain reports received during this visit.

Use Tools for location, units, distance measurement, full screen, credits and help. Labels, launch sites, milestones, the floating legend and coordinates are optional in Layers. Location stays in your browser. On touch screens the optional coordinate readout shows the map center.

JTWeatherNow Live Radiosondes · Build 1.4.0

Data credits

Telemetry and trajectory predictions: SondeHub and its contributors. The API declares CC BY-SA 2.0. Returned data is filtered to the lower 48, normalized, deduplicated and sampled by JTWeatherNow; the processed data is offered under that license.

State and county outlines: US Census Bureau, 2024 cartographic boundaries at 1:20m scale. Basemap providers are credited on the map. Leaflet is distributed under its included BSD-2-Clause license.