Reservoir · Colorado · United States · BOR RISE
Lake Granby
Lake Granby and Dam
53.2% full
Capacity
665.78 hm³
Volume stored
354 hm³
Coordinates
40.182°N, 105.871°W
Last updated
2026-09-09
Current fill
53.2%vs 7 days ago
-1.4%losing
vs 1 year ago
-33.2%year-over-year
7-day trend
→stable
Data source: BOR RISE — US Bureau of Reclamation — daily reservoir storage volume. Capacity is the design (normal full-pool) capacity from the US National Inventory of Dams (NID); fill % = current volume ÷ design capacity. Last reading: 2026-09-09.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 40.182, -105.871 · Open in Google Maps
About Lake Granby
As of September 9, 2026, Lake Granby is filled to 53.2% of its total capacity, holding roughly 354 hm³ of water out of a maximum 666 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has held broadly steady (-1.4 pts), and it is 33.2 points below its level on the same date a year earlier.
Across the readings we hold for Lake Granby — 1949 data points between September 12, 2021 and September 9, 2026 — the level has ranged from a low of 53.2% (September 9, 2026) to a high of 99.3% (July 8, 2023). On average the reservoir is fullest around July and at its lowest around March.
It is operated by BOR primarily for multiple purposes. It lies within the Colorado basin at 40.182°N, 105.871°W.
Key facts
- Current fill level
- 53.2%
- Water stored
- 354 hm³
- Total capacity
- 666 hm³
- 7-day change
- ▼ 1.4 pts
- Year-on-year
- ▼ 33.2 pts
- Primary use
- Multipurpose
- River basin
- Colorado
- Operator
- BOR
- Coordinates
- 40.182°N, 105.871°W
- Last updated
- September 9, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 9 Sep 2026 | 53.2% | 354 |
| 8 Sep 2026 | 53.4% | 355 |
| 7 Sep 2026 | 53.6% | 357 |
| 6 Sep 2026 | 53.8% | 358 |
| 5 Sep 2026 | 54.1% | 360 |
| 4 Sep 2026 | 54.3% | 361 |
| 3 Sep 2026 | 54.4% | 362 |
| 2 Sep 2026 | 54.6% | 364 |
| 1 Sep 2026 | 54.8% | 365 |
| 31 Aug 2026 | 54.9% | 366 |
| 30 Aug 2026 | 55.1% | 367 |
| 29 Aug 2026 | 55.3% | 368 |