Lake Eloise algae history from satellite

We read Lake Eloise from 419 cloud-free satellite scenes between Feb 14, 2016 – Sep 19, 2026. Here is what the surface water showed.

Clear scenes: 419
Typical (median), index: 100
Highest reading: 291 · May 14, 2016
Latest scene: 97 · Sep 19, 2026

Algae signal (red-edge index) over time

Algae signal (red-edge index), index. One dot per cloud-free scene; dates are local to the lake.

When it peaks

Month	Clear scenes	Median, index	Scenes rated high
Jan	24	98	92%
Feb	34	95	82%
Mar	33	83	70%
Apr	34	103	41%
May	38	104	34%
Jun	37	112	24%
Jul	35	107	37%
Aug	35	117	80%
Sep	40	108	83%
Oct	36	117	94%
Nov	40	99	90%
Dec	33	91	79%

By year (median / highest): 2016: 158 / 291 (12 scenes) · 2017: 67 / 91 (20 scenes) · 2018: 100 / 142 (48 scenes) · 2019: 75 / 151 (42 scenes) · 2020: 86 / 180 (40 scenes) · 2021: 127 / 232 (46 scenes) · 2022: 82 / 151 (44 scenes) · 2023: 107 / 165 (43 scenes) · 2024: 110 / 171 (37 scenes) · 2025: 126 / 190 (54 scenes) · 2026: 93 / 148 (33 scenes).

What a satellite can and can’t tell you

Satellites see only the surface layer, only on cloud-free days, and only away from the shoreline. They estimate algae; they do not measure toxins, and they can’t see what the lake bottom is doing. A clear reading is not a safety clearance.

For current conditions and health advisories, check the Florida DEP algal bloom page and the Florida Department of Health. If a person or pet may have been exposed to a bloom, call a doctor, a veterinarian, or Poison Help at 1-800-222-1222.

Source: Sentinel-2 MSI (ESA Copernicus), Red-edge cyanobacteria index (CI-cyano); a scene counts as a bloom when the index is above 50 and stays high relative to turbidity (bloom rule v1 (2026-10)). Snapshot exported Oct 9, 2026.

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Month	Clear scenes	Median, index	Scenes rated high
Jan	24	98	92%
Feb	34	95	82%
Mar	33	83	70%
Apr	34	103	41%
May	38	104	34%
Jun	37	112	24%
Jul	35	107	37%
Aug	35	117	80%
Sep	40	108	83%
Oct	36	117	94%
Nov	40	99	90%
Dec	33	91	79%

Month	Clear scenes	Median, index	Scenes rated high
Jan	24	98	92%
Feb	34	95	82%
Mar	33	83	70%
Apr	34	103	41%
May	38	104	34%
Jun	37	112	24%
Jul	35	107	37%
Aug	35	117	80%
Sep	40	108	83%
Oct	36	117	94%
Nov	40	99	90%
Dec	33	91	79%

Month	Clear scenes	Median, index	Scenes rated high
Jan	24	98	92%
Feb	34	95	82%
Mar	33	83	70%
Apr	34	103	41%
May	38	104	34%
Jun	37	112	24%
Jul	35	107	37%
Aug	35	117	80%
Sep	40	108	83%
Oct	36	117	94%
Nov	40	99	90%
Dec	33	91	79%