3,340 ft · Sandwich Range · month-by-month from 251 observed days
3,340 ft | Sandwich | 0 routes
April through September is the reliable window: 91% of observed days rated Good or Moderate. March was the toughest month, with 76% of days at Difficult or worse.
Bar shows the share of observed days at each severity; the number is the share rated Good or Moderate. Good · Moderate · Difficult · Dangerous
| Month | Days observed | Good/Moderate | Recurring hazards |
|---|---|---|---|
| February | 27 | 37% | severe wind chill, ice, postholing, snow |
| March | 29 | 24% | ice, snow, postholing, severe wind chill |
| April | 30 | 60% | mud, ice, severe wind chill, snow |
| May | 31 | 84% | mud, ice |
| June | 30 | 100% | mud, slick ledges, ice |
| July | 31 | 100% | mud, slick ledges |
| August | 31 | 100% | mud, slick ledges |
| September | 30 | 100% | mud, slick ledges, severe wind chill |
| October | 12 | 100% |
Right now on Middle Sister
Moderateupdated Oct 17, 3 AMApril through September is the reliable window: 91% of observed days rated Good or Moderate. March was the toughest month, with 76% of days at Difficult or worse.
Yes, with winter gear and experience: in our observations, 70% of December-March days rated Difficult or Dangerous. Full winter traction, insulation, and a hard turnaround plan are the baseline; check live conditions the morning you go.
Methodology: severity shares are observed, not forecast. Each day's rating is the consensus of our AI-synthesized condition reports for Middle Sister that day, collected since February 2026 (251 days so far). Months keep filling in as the archive grows. Pair the history with the live report and a summit forecast before you commit to a drive.
| severe wind chill, slick ledges, ice, mud |