About & data

This page shows sun and shade on Lizard Island, a small wooded island in a lake in a botanic garden in Miami. The sun map comes from a lidar scan of the island's trees; the satellite picture and the nearby weather are live. Everything here is shown as it is: a model where it is modelled, and off-site where it is measured somewhere else.

The sun map

A lidar survey of the island in October 2025 recorded its trees and ground as billions of laser points. The model turns them into 10 cm cubes of leaves, branches and ground, each partly see-through by how dense it is. For each position of the sun it follows the sun's rays through the cubes and works out, for every 10 cm spot seen from above, the share of it that the sun reaches directly. That share is what the map colours: dark blue is deep shade, gold is full sun.

Sun now is that share at the present moment. Sun so far today adds it up since sunrise, in minutes, every 5 minutes. Share of the island in sun is the mean share over the island's land, including the canopy that stands over the water.

Limits

• Clear sky. The map shows where the sun would reach if no cloud were in the way. It does not know about cloud; the satellite picture is shown beside it for that.
• One canopy for every date. The trees are as scanned in October 2025. Leaves that have grown or fallen since, and any storm damage, are not in the model.
• Direct sun only. Light from the open sky and light bounced off leaves are not included, so a shaded spot is not dark.
• A lit share, not the sun's strength. A value of 50% means half of the spot is in direct sun. It is not watts per square metre.
• Low sun. In the first 40 minutes after sunrise and the last 30 before sunset, the sun shines in over trees and buildings beyond the scan, which the model can only guess at. Cells where the share could be 0.2 or more higher are hatched: up to about a tenth of the island at those times, none in between.
• Accuracy between sun positions. The model is worked out for sun positions one degree apart and blended between them. Against two-minute steps on a test day the share was off by about 0.01 on average, and the minutes of sun in a day by about half a minute.

Satellite: the last hour

The pictures are from the GOES-19 weather satellite, which scans the United States every 5 minutes. The page loops the last hour of scans, twelve frames, on a 30 km square around the island with north up; the ring marks the island and the bar is 10 km. While the sun is more than 5° up it uses the red visible band (band 2, pixels about 0.5 by 0.6 km here), otherwise the infrared band (band 13, about 2 by 2.4 km here), and each frame says which. The words under each frame come from NOAA's clear sky mask for the 2 km pixel that holds the island in that scan: clear, probably clear, probably cloudy or cloudy.

• The frames are enlarged smoothly from the satellite's pixels, 50 to 60 across the square by day and 13 to 15 at night, so anything smaller than a pixel is not real detail. At night only clouds colder than the sea show, and low cloud shows faintly.
• Visible frames are brightened when the sun is low, so that they do not fade to black before the switch to infrared.
• The island, about 90 by 140 m, is a small part of one 2 km pixel, so a small cloud over the island can be missed and a cloud nearby can be counted.
• Seen from the satellite, a cloud appears shifted north-north-west by about 0.6 times its height: a cloud 1 km up shows about 600 m from where it is.
• The scan reaches the island about 3 minutes after each 5-minute mark and the files arrive 1 to 2 minutes later, so the picture is usually 4 to 9 minutes old.
• The clear sky mask for GOES-19 is a provisional product.

Nearby weather

Until the island's own weather station is installed, the weather shown is from two stations nearby. Neither is on the island and both are by open water, so the island's shade and shelter make it differ.

• Virginia Key, NOAA tides and currents station 8723214, on Biscayne Bay about 12 km east-north-east: air temperature and wind every 6 minutes.
• Miami International Airport (KMIA), about 13 km north-north-west: the hourly airport weather report (METAR), for humidity, sky cover and the heat index.

Vegetation height and base map

Vegetation height is the height of the tallest plants above the ground or water in each 25 cm cell, from the same October 2025 scan, cleaned of equipment and stray points. The photo under the maps is a drone mosaic flown in October 2025.

Sunrise, sunset and the sun's position

Worked out from the date and the island's position with NOAA's solar calculator equations. Sunrise and sunset are when the top of the sun meets a level horizon, so the island itself is in sun a little later and in shade a little earlier.

Feed status

Updated every 5 minutes. A feed that fails keeps its last good values and is marked here as old.

Sources

• Lidar survey of the island, October 2025, the drone photo of the same month, and the sun model built from them.
• GOES-19 ABI imagery and clear sky mask: NOAA, from the public NOAA Open Data bucket.
• Virginia Key station 8723214: NOAA Center for Operational Oceanographic Products and Services.
• Miami airport METAR: aviationweather.gov, NOAA National Weather Service.
• Text set in Inter (SIL Open Font License), served from this site.

Coming later

• The island's own weather station: temperature, humidity, wind, rain, leaf wetness and sunlight, measured on the island.
• Sun so far today weighted by the measured sunlight, not only clear sky.
• Seasons, and the island in 3D.