Commuting - Calculating commute time with the weather

What are your rules for commuting in the cold weather for alloting enough time? Like your commute takes 30 min on a summer day with the wind at your back, dry pavement with all the lights in your favor. How much time do you give yourself when there is a fresh snow fall? Or it got colder than a witch"s left ***, and the roads are icey? Just wondering as I have an hour and a half commute, I give my self two hours to do it, but is that going to be enough?

In the morning I try to avoid sweating so I go slower. However, the colder it gets, the faster I can go.

As long as it's dry, I can dress for conditions and find the cooler temps more comfortable.

Now just how cold is a witches left ***? Always wondered. I go slower when it's cold, not cause I'm being careful, but involuntarily. I'm not sure exactly why, but here (http://users.rcn.com/icebike/Articles/SlowerWinter.htm) are a couple thoeries. Not sure of the exact numbers either, but I'd say about 15-25% slower.

I find that bike commute times are much less affected by weather than car commute times. My half hour ride might become 45 minutes with rapidly-accumulating, untreated snow. In contrast, driving times can easily triple.

I probably go faster in the cold because I dress lightly and rely upon exertion to warm myself.

Paul

We don't actually get "cold" weather here per se. Rain doesn't bother me either way. About the only thing that slows me down is when it gets really stupidly hot (it was 34C at 7am the other morning). In those situations, I allow time to knock back an extra couple of litres of water before setting off.

Only you can tell, as many factors come into play. On a nice Winter day, my travels take about the same time as in Summer, but I don't have hills on my major routes. Keep in mind, though, that:

- Hills take more time. Downhills are limited by willpower (you need more of it in Winter) and by the fact you shouldn't take turns as quickly as on dry pavement.
Uphills take more time because you either need to unzip your coat or take it easy.

- Curves and turns. As a rule, I take them as if there was black ice. In other words: slowly.

- Snow. Fresh or old, I don't care, but it slows me down.

- Extreme congestion. My worst evening last Winter, I cycled about 2 km and walked 1,5 km. Why? Streets were too narrow, traffic was litterally crawling at 0,5 km/h, so overcrowded sidewalks with pedestrians finding their way at 2 km/h sunddently sounded like a faster alternative.
BTW, if I had been alone on the streets, I could have biked at 10-15 km/h. Not normal speed, but still decent.

What are your rules for commuting in the cold weather for alloting enough time? Like your commute takes 30 min on a summer day with the wind at your back, dry pavement with all the lights in your favor. How much time do you give yourself when there is a fresh snow fall? Or it got colder than a witch"s left ***, and the roads are icey? Just wondering as I have an hour and a half commute, I give my self two hours to do it, but is that going to be enough?

Well...when I'm flying, I manage 18.5 km in 26 Minutes when I have the lights on my side. That's roughly 42 km/h or 26 mi/hr over 11.5 miles. This is in the summer. On my flighty Carbono Treko...feeling good. Riding homewards doesn't hurt, either.

In the winter, I have managed to take the same route in over 40 minutes with the same bike. (MTB goes slower anyways) Granted, it was snowing, it was miserable cold (wet snow) and I was tired, but still...:(

So what? Basically, summer ain't winter, and I expect times of roughly 1.4-1.5 times what my best times in the summer are. I just hope for non-wet conditions, and minimal fog. That being said, it's REALLY foggy out there right now, and I have a meeting left to me (it's 8 P.M. as I write this) and I'll be riding off in the fog later. On the good side, I've got two halide lights, and 4 VistaLights. Oh, and a Schmidt Hub Dynamo. And a cateye HL300. Yeah, Mr. cycling Xmas tree, that's me... :p
Ride carefully,

Tom
Flawil, Switzerland

P.S. I'd get a set of Nokkian studded tires if I were you. I've got a icy bridge on my commute in, and they really lower the pucker factor when it's dark and cold. I've had them for one season, and they don't show any sign of wear yet.

Generally, I allow an hour in the morning and 75 minutes in the evening. Weather rarely holds me up in Atlanta, where it almost never snows. The wind is usually not that bad here, as I have rarely been held up for more than 5 minutes by a headwind. It just seems to work out that I can almost always predict my arrival time with little variation. My main hold-up, though very rare, is when I get a flat.

I am sure it's different in the Snowy Midwest where a Wind might just pick you up and land you in OZ.

:D