I use the same as non winter, since I try to pick foods that won't melt in hot temps and work okay for winter. I would keep next meal in pocket to thaw if needed. The snickers will be mushy during day in hot temps, but is firm the next morning for eating.
Breakfast: Oatmeal, snickers bar
Morning Snack: Almond M&M's
Lunch: Peanut butter crackers, fig newton bar, granola bar
Afternoon Snack: Almond M&M's
Dinner: Oatmeal, ramen, salmon or tuna, hot drink