When Does Ann Lake Freeze? Typical Ice-In Nov 21, Ice-Out Apr 16
Ann Lake in Kanabec County, Minnesota usually freezes over around Nov 21, and usually has ice-out around Apr 16, based on Minnesota DNR ice observations recorded between 1999-2013. That works out to roughly 219 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 Ann Lake
| Typical freeze-up (ice-in) | Nov 21 |
| Typical ice-out | Apr 16 |
| Earliest freeze-up on record | Nov 8, 2003 |
| Latest freeze-up on record | Dec 15, 1999 |
| Earliest ice-out on record | Mar 25, 2000 |
| Latest ice-out on record | May 16, 2013 |
| Open-water season | ~219 days |
| Winters observed | 83 |
| Location | Kanabec County, Minnesota |
These are dates, not an ice-safety reading
A typical freeze-up date tells you when Ann 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 Ann Lake has landed as early as Mar 25, 2000 and as late as May 16, 2013 — a spread of weeks around the Apr 16 median. Freeze-up has ranged from Nov 8, 2003 to Dec 15, 1999. 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. Ann Lake carries an overall water-quality grade of D — the full breakdown is on the lake report.
Source: Minnesota DNR Climate Office ice-in / ice-out records, observations from 1999-2013.