Keeping Up with Colorado Weather

On Sunday, May 20, 2001, I drove to Colorado Springs for my brother's college graduation the next morning. It was a beautiful spring day with temperatures in the 70's. Why pack a coat? Around 4 pm, the temperature began to drop. Cold rain soon began to fall, and then turned to snow, which before long was blowing sideways. Having recently moved to Colorado from Arkansas, I was flabbergasted (and pretty cold). It's just not supposed to snow in late May.

Then I looked up at the mountains and wondered how many people had been caught up there in a snowstorm they weren't prepared for. That's when I realized that Colorado weather can be unpredictable and even dangerous in a way that people from other places may not be prepared for. This was clear the next morning, when people from all over the country showed up in spring clothing for an outdoor ceremony in the snow.

Ever since then, I've been careful to check the weather before I head for the mountains on the weekend. But I've also learned to appreciate the wild weather out here. I love the afternoon thunderstorms that rumble down from the mountains in the summer, the weird flying saucer clouds that appear over mountain peaks, and the warm chinooks that melt the snow in the winter. In this post, I want to talk about some good resources for understanding how weather works, and for making sure you don't get caught out in it.

Like most people, I check the weather forecasts on TV or in the newspaper, but sometimes you need to dig a little deeper. For example, let's say you're planning a road trip for a long weekend and wondering where the weather will be nice. That's a good time to where the forecasters get their forecasts: the National Weather Service. The NWS is a federal government agency that's part of the National Oceanic and Atmospheric Administration (NOAA). NOAA and the NWS maintain a system of weather offices, stations, satellites, and labs that provide a wealth of information about weather and climate.

Let's start by going to the main National Weather Service website, at This page features a map of the United States with current weather warnings, and it can be customized to show the weather where you live. When I'm about to take a weekend trip, I like to click on the Forecast link at the top of the page, and then choose "Graphical". This takes you to a newly-developed page that lets you zoom into the region you're interested in, and then look at maps of projected temperatures, chances of precipitation, expected weather conditions, wind speed, and so on. I often go camping on weekends this time of year, so I use this tool to decide where I want to go, so I won't be camping in a snowstorm.

For more weather maps of the country, including maps of highs, lows, fronts, and so on, the Forecast Maps page is great for seeing conditions across the country at a glance. If you want the really big picture of weather across the country, check out the Daily Briefing page. This page keeps an eye on every curveball Mother Nature might throw, including earthquakes, El Ninos, tropical storms, tsunamis, and even space weather (which is monitored by the Space Weather Prediction Center in Boulder.) 

If you're mostly interested in local weather, the National Weather Service has you covered there, too. The NWS has 122 Weather Forecast Offices located around the country. Our local office is in in Boulder. The Boulder office's web page is packed with useful information, from basic local forecasts to more technical forecast discussions from meteorologists, as well as detailed maps and data from local weather observation stations. If you subscribe to the office's page on social media, you'll see nice daily infographics about the day's weather. The Boulder office also links to other local weather information, such as CDOT's page on road conditions. Finally, the Boulder NWS office has interesting text descriptions of notable local weather from the past, which can be searched by date. 

Of course, most people just check the weather by tuning into their local local news stations, or looking at commercial weather sites online. These can be much simpler to understand than some NWS sites, and often have excellent graphics. The downsides are that you have to watch a lot of ads, and it can be harder to find detailed information. Still, commercial news sites have some great information. If you want to see what conditions are on the ground, CBS Denver has webcams all around the state, including one right here on the roof of the Central Library.

While commercial weather organizations get a lot of their data from the National Weather Service, many have their own Doppler radar systems, and their radar imagery can be a little more user-friendly than the National Weather Service radar page. One commercial site I find really useful is Intellicast's Interactive Weather Map, which lets you select and view a wide range of different variables. The one I check most this time of year is snow depth. As a hiker, a map of snow depth on the ground helps me find trails in the mountains that don't require snowshoes. Speaking of snow, it's never a bad idea to check the Colorado Avalanche Information Center if you're headed into the high mountains. 

Modern weather forecasts are made using every level of technology--from geostationary satellites and supercomputer modeling to networks of volunteers checking rain gauges. All these systems collect massive amounts of data, which is often accessible online. But much of it can be hard to understand without a basic sense of how meteorology works. Luckily, there are a lot of great resources for that, too. 

DPL has some great books about weather and climate. Since Colorado has such variable, hard-to-predict weather, one I really recommend is Colorado Weather Almanac, by Mike Nelson, the Chief Meteorologist at Denver7. It has great discussions of the basics of meteorology as it relates to our local climate. For a wider-angle view of meteorology, there's a brand new book called Weather: An Illustrated History. It's full of gorgeous illustrations of all aspects of weather and climate. Another well-illustrated book on weather and forecasting is Weather: A Visual Guide. If cloud-watching is your thing, there's the The Cloudspotter's Guide: The Science, History, and Culture of Clouds. The author also has a nice Ted talk on the beauty of clouds. 

There's also a lot of excellent educational material online. For a basic introduction to weather, Colorado's own UCAR Center for Science Education has a nice site. Another great resource for visual learners like me is Learn About the Weather, a series of well-made videos on meteorology from the Met Office, the UK's version of the NWS. The drawback of these is that they focus on weather patterns in the UK, so they aren't perfectly applicable to North American weather. But they're still worth watching, because they have some of the best explanations I've seen of things like global air circulation and the Coriolis effect. If you're ready to dig in to the technical aspects of meteorology, you can't beat JetStream, an interactive "online school for weather" from the National Weather Service. 

These resources make it much easier to understand the great wealth of data from satellites, radar, weather station networks, and volunteer weather observers (one of whom is a senior librarian in Reference Services). They may also help with interpreting historical data like the official datasets from NOAA's National Centers for Environmental Information.

When you start looking at historical trends, though, you're talking about long term climate, not short term weather, and that's a topic that merits a blog post of its own. That post is forecast to appear in the next few weeks.

Got questions?  Ask Us or call Reference Services at 720-865-1363! 

Written by Ross on May 16, 2018


Roger D. on May 19, 2018


There is a 20% chance of precipitation in Denver everyday no matter what the weather forecasters tell you. Temperature drops of 50 degrees in a day are not uncommon. That's why layers are the ONLY way to dress.