When Does Roosevelt Lake Freeze? Typical Ice-In Dec 10, Ice-Out Apr 19
Roosevelt Lake in Cass County, Minnesota usually freezes over around Dec 10, and usually has ice-out around Apr 19, based on Minnesota DNR ice observations recorded between 2006-2022. That works out to roughly 235 days of open water a year. These are typical dates across many winters, not a forecast — individual years swing by weeks in either direction.
Ice record for Roosevelt Lake
| Typical freeze-up (ice-in) | Dec 10 |
| Typical ice-out | Apr 19 |
| Earliest freeze-up on record | Nov 28, 2018 |
| Latest freeze-up on record | Dec 21, 2006 |
| Earliest ice-out on record | Apr 6, 2021 |
| Latest ice-out on record | May 7, 2022 |
| Open-water season | ~235 days |
| Winters observed | 41 |
| Location | Cass County, Minnesota |
These are dates, not an ice-safety reading
A typical freeze-up date tells you when Roosevelt Lake has usually iced over — it does not tell you the ice is safe, and we hold no thickness measurement for this or any lake. The Minnesota DNR is explicit that no ice is ever completely safe: thickness varies across a single lake, and current, springs, aerators, and insulating snow all weaken it. Ice that held a truck last week may not hold a person today.
Read the ice-thickness guidelines before going out, and check current conditions with the Minnesota DNR ice-safety page and local bait shops, which track conditions lake by lake.
How much the timing varies
Ice-out on Roosevelt Lake has landed as early as Apr 6, 2021 and as late as May 7, 2022 — a spread of weeks around the Apr 19 median. Freeze-up has ranged from Nov 28, 2018 to Dec 21, 2006. That year-to-year swing is why a median date is a planning tool, not a schedule. Freeze-up is driven by accumulated cold after the lake turns over in fall; ice-out by late-winter air temperature, sun angle, and how much snow sits on top of the ice reflecting it. Roosevelt Lake carries an overall water-quality grade of A — the full breakdown is on the lake report.
Source: Minnesota DNR Climate Office ice-in / ice-out records, observations from 2006-2022.