When Does Green Lake Freeze? Typical Ice-In Dec 2, Ice-Out Apr 10
Green Lake in Isanti County, Minnesota usually freezes over around Dec 2, and usually has ice-out around Apr 10, based on Minnesota DNR ice observations recorded between 2000-2014. That works out to roughly 236 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 Green Lake
| Typical freeze-up (ice-in) | Dec 2 |
| Typical ice-out | Apr 10 |
| Earliest freeze-up on record | Nov 20, 2000 |
| Latest freeze-up on record | Dec 20, 2001 |
| Earliest ice-out on record | Mar 22, 2000 |
| Latest ice-out on record | Apr 27, 2014 |
| Open-water season | ~236 days |
| Winters observed | 19 |
| Location | Isanti County, Minnesota |
These are dates, not an ice-safety reading
A typical freeze-up date tells you when Green 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 Green Lake has landed as early as Mar 22, 2000 and as late as Apr 27, 2014 — a spread of weeks around the Apr 10 median. Freeze-up has ranged from Nov 20, 2000 to Dec 20, 2001. 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. Green Lake carries an overall water-quality grade of C — the full breakdown is on the lake report.
Source: Minnesota DNR Climate Office ice-in / ice-out records, observations from 2000-2014.