May 17, 2013

Biking Dry

Today is bike to work day and thus there is no better time to discuss how you can bike on most days without fear of getting wet....or at least very wet.

Yes, even here in the Pacific Northwest a little meteorological knowledge and technology can help you avoid those raindrops and enjoy a very pleasant ride on your bicycle.

You might be surprised, but the Northwest is one of the best places to bike commute or enjoy recreational biking in the nation.

Think about it.  What are the worst conditions for biking?  That's easy:  icy and snowy roads.  It's cold and accidents are inevitable.   Good news: western Oregon and Washington have very little snow and ice.

Biking is miserable in hot, humid weather like during summer in the southeast U.S. and the extreme heat of the southwest.  Again, we luck out:  we rarely see such conditions.

Very heavy precipitation, such as in thunderstorms. is really bad for biking and lightning is dangerous.  No problemo here!--we get less thunderstorms than almost anyone else.

Ah, yes, the rain.   But consider our rains are concentrated in only a few months (November through February) and the rest of the year is really pretty dry.  Our annual precipitation (e.g.,  Seattle gets about 37 inches a year) is far less than most of the central and eastern parts of the U.S.  And when it does rain, it is generally quite light;  a rain resistant jacket and pants, coupled with our mild temperatures, leads to a pleasant ride.

 Heavy showers like this are very rare in the Northwest.

But it gets even better for you bicycle commuters and enthusiasts!  Even when we have wet days it rarely rains steadily for a long period of time.  If you can shift your trip by a few minutes, you can often escape the rain.  I bike to work nearly every day and rarely get very wet.

Case in point, the in famous shower and sunbreaks.   Much of our precipitation comes after a front goes by and we get into cool, unstable air.  Such precipitation is convective, meaning we get hit by a shower and then there is a break, followed by another shower an hour or more later.    Here is a radar image showing you an example of this....the showers are coming in from offshore.

Such rain is easy to avoid, wait for the shower to pass and then head out on your bike.
And even in other weather situations rain is almost never uniform and all you have to do is make sure you wait for the dry or light rain areas. 

How can you do that?   Smartphone technology solves this problem!    There are now hundreds of weather radar apps that give you the latest radar image and a radar animation.  It even shows where you are on the image using the GPS or cell-tower navigation function on your phone.  Easy to see the dry spots coming!  And some radar apps will even tell you exactly when the radar will start.  Some are free, but the best ones cost a few dollars.   I use Radarscope (see image below) and some folks use DarkSky, which gives you the timing (but reviews are mixed on this one).

Radarscope (left) and DarkSky (right).

I have been trying to convince a few of my students to create a weather-radar-based bicycle app, where you put in your route and tells you when the coast is clear.

And one more thing.  It is virtually NEVER raining everywhere around here because of our mountains.  If there is a convergence zone going on, with precipitation over north Seattle, head north or south for a dry ride.   Wet frontal system over the entire region, with typical southwesterly flow?  No problem, head to Sequim, Port Townsend, or northern Whidbey.  

Announcement:   I will be teaching Atmospheric Sciences 101 (WEATHER) at the UW this fall.  This class is accessible folks 60 or older at very little cost (the UW Access Program) and, of course, to regular UW students.  This class will give you a good basic understanding of the atmosphere and Northwest weather.

 Our Mayor knows how to find the dry spells.


  1. Love your blog! Very useful to send students to to gain an understanding of weather phenomena.

    I bike to work also; all of your hints are very useful and I follow them too. I've found to make use of the rain breaks you only need to allot an extra 20 - 30% of the time it actually takes to bike to arrive in a timely manner, assuming you have to wait out a downpour. Perhaps your grad students could model the best amount of extra time one should allot given historic trends in weather patterns.

  2. Cliff, I really appreciate your post. I bicycle commute year-round, 2 or 3 times a week, from downtown town Seattle to Bothell, and I'm always getting comments about how wet I must get. As you say, its just not true ( most of the time)! I get good exercise, get outside, enjoy a part of the day most commuters dread, and am not burning gas for my commute. And its true, those apps give a good picture of how to avoid the real downpours. Gear and lights are essential in the darker months though!

  3. I've given most of the radar apps a try, and I find that, at least for biking, the low resolution of the map in RadarScope is a problem. Also, it only displays one radar station at a time. And I find Dark Sky's predictions to be very inaccurate (sometimes hilariously so).

    My personal preference is for the NOAA SuperRes app -- it has both high resolution maps and high resolution radar.

  4. I am always so disappointed by the bike commute nonsense and the Gold certifications for Biz Cycle, trumpeted by the Cascade Cycling Club and all of the wasted millions of taxpayer dollars on bike programs.

    There is certainly nothing wrong with cycling to work. It's great exercise and cycling in general is great. I am an avid cyclist who has been riding for 35 plus years and who will ride STP in July. And I have occasionally commuted to work by bike when I have have jobs that took me to the same nearby site each day.

    But the assumption of so much of the Nickels driven movement is that bicycle commuting will ever amount to an important percentage of daily trips in a climate such as ours. This is utterly ridiculous. As much as us enthusiasts enjoy cycling, the vast majority have **ZERO** desire to get cold, wet or sweaty on the way to work. And/or have commutes that are far too long and far too dangerous to do by bike.

    And I have such a hatred for those who I view as Biketivists and not true cyclists. If you want to run lights and stop signs, participate in Critical Mass, and ride main streets of downtown Seattle dangerously and like you own the road, you ARE the problem and the reason so many of us real cyclists get a bad rap.

    Let's get over this inane indulgence to our own enthusiasm for cycling and all of the intertwined political BS and spend our limited transit dollars on far more important modes of travel that transit the vast majority of goods, services and people.

    If you want to cycle to work, do it on your own dime, and be smart enough to take secondary arterial streets instead of expecting autos at speed to yield to your every whim and to give up their much needed lane space to cyclists who think they own the road.

    And for the love of two wheels, obey all traffic laws and have some respect for the pedestrians and autos with whom you share the road.

  5. I would be using that app today! Students, let me know when to beta test.

  6. An excellent resource here in Seattle is Jeff Baars' Rainwatch, which provides instant precip and a 1-hour forecast. It is not an app, and is free, meaning that it is accessible to any computer or mobile device (including dumbphones with a web browser).

    Direct link to the 1-hour forecast:


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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