The coldness of winter means people are staying indoors, sitting on couches ... and ordering food delivery. But does knowledge that delivery men are trudging through awful conditions affect tips consumers give? Does the winter bring a pickup in generosity, and is that pickup split evenly across the country? More interestingly, can specific food items ordered help predict the size of the tip?
For a deeper look at the intersection of food, generosity and economics, we turned to the data pros at online food ordering site GrubHub, who analyzed winter tipping behaviors for CNBC.
There may even be a connection between best-tipping city Denver and the legalized use of recreational marijuana in that state. But more on that later.
First, we looked at the type of food items that see the biggest pop in orders as temperatures drop.
Turns out junk food such as pizza slices help predict the biggest tips. When slices are included in an order, tips rise significantly from the 13.9 percent year-round national average to 16.4 percent, a full half-point ahead of all other foods ordered. Pizza was the only food item to pocket a tip over 16 percent.
Breakfast items also help signal bigger tips, in part because even a buck tip on a small order can have a big impact. As one economic analyst suggested, "Breakfast tips percentage-wise are pretty impressive, but that's what tipping a dollar on a bagel will do."
A marijuana connection?
Beyond just food items, some cities tend to tip better than others for all kinds of goods and services. The best tipping city in the winter is none other than Denver, according to GrubHub. With an average tip of 15.7 percent during the winter, Mile High residents tip a full 60 basis points higher than the next best tipping town.
Given Colorado's legalized recreational use of marijuana, you can't help but imagine connections among marijuana consuming regions, home delivery and specific foods that signal tipping generosity, including pizza.
So if the best tipping city is Denver, and ordering pizza predicts the largest tips, we can attempt to predict the future and wonder if delivery businesses will experience a boon as recreational marijuana use becomes legalized across the country.
Beyond Denver, the next-best tipping towns tend to be in places such as Texas, Virginia and Tennessee. Sort the table below to see the top city rankings for tips.