{"id":3350,"date":"2025-04-28T07:46:36","date_gmt":"2025-04-28T06:46:36","guid":{"rendered":"https:\/\/mywindsock.com\/page\/?p=3350"},"modified":"2025-04-28T07:46:38","modified_gmt":"2025-04-28T06:46:38","slug":"how-does-a-mywindsock-forecast-actually-work","status":"publish","type":"post","link":"https:\/\/mywindsock.com\/page\/discussion\/how-does-a-mywindsock-forecast-actually-work\/","title":{"rendered":"How Does a myWindsock Forecast Actually Work?"},"content":{"rendered":"\n<p>If you&#8217;ve ever looked at your ride on myWindsock, you know how important the weather is for cycling. Headwinds, tailwinds, air pressure, and even temperature can affect your speed and effort. But where does this weather data actually come from?<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"1024\" height=\"920\" src=\"https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2024\/03\/Screenshot-2024-03-26-at-15.51.19-1024x920.png\" alt=\"\" class=\"wp-image-3091\" srcset=\"https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2024\/03\/Screenshot-2024-03-26-at-15.51.19-1024x920.png 1024w, https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2024\/03\/Screenshot-2024-03-26-at-15.51.19-300x269.png 300w, https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2024\/03\/Screenshot-2024-03-26-at-15.51.19-768x690.png 768w, https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2024\/03\/Screenshot-2024-03-26-at-15.51.19.png 1176w\" sizes=\"(max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><\/figure>\n\n\n\n<h2>What Is a Weather Forecast?<\/h2>\n\n\n\n<p>A weather forecast is a prediction of what the weather will be like in the future \u2014 whether that\u2019s in the next hour or several days ahead. Forecasts tell us things like:<\/p>\n\n\n\n<ul><li>How strong the wind will be<\/li><li>What direction it will blow<\/li><li>Whether it will rain<\/li><li>What the temperature and air pressure will be<\/li><\/ul>\n\n\n\n<p>These forecasts help cyclists plan everything from clothing choices to pacing strategies. But how do we know what the weather will do?<\/p>\n\n\n\n<p>Forecasts are made using something called weather models. These are complex computer programs that simulate the atmosphere using current weather observations. There are many different weather models used around the world, and a rider in the UK might see forecasts based on models like the UK Met Office&#8217;s UKV model, the European Centre for Medium-Range Weather Forecasts (ECMWF) model, or the Global Forecast System (GFS) model. Each model has different strengths \u2014 some are better at short-term, very local predictions, while others excel at longer-range forecasting across wider areas.<\/p>\n\n\n\n<p>Here\u2019s a simplified version of how it works:<\/p>\n\n\n\n<ol><li>Observation: Weather stations, satellites, balloons, aircraft, and ships collect data from all over the world. This includes temperature, wind, humidity, and more.<\/li><li>Analysis: This data is fed into supercomputers that look at current weather patterns.<\/li><li>Modeling: These computers run simulations based on the laws of physics to predict how the atmosphere will behave in the future.<\/li><li>Forecast Output: The result is a weather forecast \u2014 including maps, numbers, and wind arrows \u2014 like the ones myWindsock uses to simulate your ride<\/li><\/ol>\n\n\n\n<p>myWindsock uses forecasts, not just current conditions. That means when you plan a ride for tomorrow or analyse one from last weekend, the weather details are based on predicted conditions that change across time and distance \u2014 exactly what you need to understand how the wind or rain helped or hindered your ride.<\/p>\n\n\n\n<p>myWindsock uses forecasts, not just current conditions. That means when you plan a ride for tomorrow or analyse one from last weekend, the weather details are based on predicted conditions that change across time and distance \u2014 exactly what you need to understand how the wind or rain helped or hindered your ride. <\/p>\n\n\n\n<h2>What do we do with the weather forecasts and why isn\u2019t it always perfect? <\/h2>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><img loading=\"lazy\" width=\"1024\" height=\"313\" src=\"https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.32.55-1024x313.png\" alt=\"\" class=\"wp-image-3352\" srcset=\"https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.32.55-1024x313.png 1024w, https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.32.55-300x92.png 300w, https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.32.55-768x235.png 768w, https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.32.55-1200x367.png 1200w, https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.32.55.png 1368w\" sizes=\"(max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><figcaption>Forecasts often disagree, for example today where I am it is simultaneously 13 degrees with light showers as well as 8 degrees and snowing. This is a short term forecast for the next few hours, as you can imagine weather models disagreeing with each other is a cause of headaches for us. <\/figcaption><\/figure><\/div>\n\n\n\n<p>As you\u2019ll know, weather forecasts aren\u2019t always perfect and these models have errors associated with them. These errors propagate through the myWindsock physics models (the things we use to work out how fast you\u2019ll go over a given distance (so if the weather model says the wind will blow faster than it ends up blowing, even if our physics engine is perfect, the prediction will be wrong). Of course, here at myWindsock we spend time accounting for this and doing what we can but it\u2019s a reality of trying to make an extremely complicated prediction.\u00a0<\/p>\n\n\n\n<h2>How do we make predictions? <\/h2>\n\n\n\n<p>The best way to think about it is by considering the \u201cequation of motion\u201d of a cyclist. An \u201cequation of motion\u201d is something physicists use in order to model something. Now, I\u2019ll let you into a secret &#8211; there\u2019s always stuff that physicists just don\u2019t count because the effects are small or including it just makes the mathematics a bit too hard. What you have to do is think of all the things speeding the cyclist up (pedal force, tailwind force etc) and all the things slowing the cyclist down (headwind force\/air resistance, rolling resistance etc) and add these up. Once you do that, you\u2019re left with a number which will either be positive or negative which tells us whether or not the bike is speeding up or slowing down.<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><img loading=\"lazy\" width=\"1024\" height=\"494\" src=\"https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.41.23-1024x494.png\" alt=\"\" class=\"wp-image-3353\" srcset=\"https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.41.23-1024x494.png 1024w, https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.41.23-300x145.png 300w, https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.41.23-768x371.png 768w, https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.41.23-1200x579.png 1200w, https:\/\/mywindsock.com\/page\/wp-content\/uploads\/2025\/04\/Screenshot-2025-04-28-at-08.41.23.png 1218w\" sizes=\"(max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><figcaption>This diagram, from <a href=\"https:\/\/link.springer.com\/article\/10.1007\/s12283-018-0283-0\">a paper published in an academic journal<\/a>, shows us roughly the forces acting on a bike (but it leaves out drivetrain resistance). The main point I\u2019m trying to make here is that there\u2019s quite a lot going on all at once. The air resistance force that we predict is a function of the weather forecast and the rolling resistance force that users enter using the myWindsock advanced settings is actually a function of the pavement so is rarely (almost never) a static value for the entire ride.\u00a0<br><\/figcaption><\/figure><\/div>\n\n\n\n<p>We have a physical model similar to the one above which does all of this &#8211; some of the inputs come from the user (like power numbers and the gradients from the GPX file you use as well as rolling resistance in advanced settings) and others from the weather forecast models. We then add all of these up, calculate the forces at each step along the course, use the result of this calculation to figure out the speed then add these speeds up to get a time prediction at the end of the course (if you\u2019ve already don\u2019t the course and upload a ride file, we do all of this backwards and figure out the resistive forces instead).\u00a0<\/p>\n\n\n\n<h2>What can you do improve your predictions?\u00a0<\/h2>\n\n\n\n<p>If you find that our predictions are off, there\u2019s two steps you can take\u2026&nbsp;<\/p>\n\n\n\n<ol><li>Make sure the forecast you use is as recent as possible &#8211; so update the forecast. It will change from the one you made 2 weeks out, as you\u2019ll have experienced weather forecast accuracy decays with time from the date you\u2019re trying to forecast.<br><\/li><li>Check your settings &#8211; bike weight, cda, rolling resistance and such, take some time to make sure these values are as close to accurate as possible. Methods for doing this could (and probably will) make an entire blog in their own right.\u00a0<\/li><\/ol>\n\n\n\n<p>While weather forecasting and physics modeling will never be perfect, myWindsock brings you as close as possible to understanding how the conditions around you shape your ride. We are the best in the business. By blending cutting-edge atmospheric data with detailed physics simulations, we offer a powerful tool to plan, analyse, and learn from your efforts on the bike. And with a little help from you\u2014up-to-date forecasts and dialled-in ride settings\u2014we can make those predictions even better. After all, cycling may be part science and part suffering, but we\u2019ll do everything we can to take the guesswork out of the wind.\u00a0<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>If you&#8217;ve ever looked at your ride on myWindsock, you know how important the weather is for cycling. Headwinds, tailwinds, air pressure, and even temperature can affect your speed and effort. But where does this weather data actually come from? What Is a Weather Forecast? A weather forecast is a prediction of what the weather &hellip; <a href=\"https:\/\/mywindsock.com\/page\/discussion\/how-does-a-mywindsock-forecast-actually-work\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;How Does a myWindsock Forecast Actually Work?&#8221;<\/span><\/a><\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[3],"tags":[],"_links":{"self":[{"href":"https:\/\/mywindsock.com\/page\/wp-json\/wp\/v2\/posts\/3350"}],"collection":[{"href":"https:\/\/mywindsock.com\/page\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mywindsock.com\/page\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mywindsock.com\/page\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/mywindsock.com\/page\/wp-json\/wp\/v2\/comments?post=3350"}],"version-history":[{"count":1,"href":"https:\/\/mywindsock.com\/page\/wp-json\/wp\/v2\/posts\/3350\/revisions"}],"predecessor-version":[{"id":3354,"href":"https:\/\/mywindsock.com\/page\/wp-json\/wp\/v2\/posts\/3350\/revisions\/3354"}],"wp:attachment":[{"href":"https:\/\/mywindsock.com\/page\/wp-json\/wp\/v2\/media?parent=3350"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mywindsock.com\/page\/wp-json\/wp\/v2\/categories?post=3350"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mywindsock.com\/page\/wp-json\/wp\/v2\/tags?post=3350"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}