Wintrodynamics

As you make the transition to winter months, a typical day may be less productive due to the following reasons.
->Inertia to wake up - increases with decreasing temperatures -> potentially 1/2 hour to 1 hour delay in getting up from bed.
->Increase in shower time - If you feel like spending the rest of the day in the warm water on a wintry day, you know what I'm talking about -> 10 minutes to upto 1/2 hour increase
=> Delay in getting to office - On an average 1 hour delay in reaching office due to the above reasons.
->Shorter days-Thanks to daylight savings, it gets dark soon. It has a psychological effect, doesn't it? Feels like good amount of useful time is already gone, time to go home. Typically you might leave an hour earlier.
==>less productivity - Above things add up to bring down your productivity. Your work day shrinks down on an average by a good 2 hours.

There is an innate positive feedback during wintry months, resulting in increased laziness, which left unchecked can be a disaster.
=> Cold temperatures -> less outdoor activity -> couch potato -> potentially results in increased laziness (results in more procrastination and so on) -> less outdoor activity -> couch potato->..........

Only a rise in will power can stabilise the system. Normally people are bound to stabilise the system by impending deadlines at work or home or for numerous other reasons.