Why 26m?
The domain was registered out of a simple obsession with distance running — specifically the marathon, and the peculiar hold it has over people who don't particularly enjoy distances shorter than ten miles. The "m" stands for miles, meters, marathon, and something harder to define: the particular mindset of someone who chooses to do this on purpose.
The site has been through several incarnations. Early versions were race reports and training logs. A long middle chapter was dedicated to weather tools — the most-requested feature was always some version of "is it okay to run outside today?" That chapter is being revisited, rebuilt properly, and made available as a free tool with no strings attached.
The run calculator — a brief history
The original weather calculator launched in the mid-2000s and ran for almost a decade. At its peak it was answering tens of thousands of questions per month from runners who just wanted a straight answer. It was simple: enter your conditions, get a score, get a clothing recommendation. No tracking, no accounts, no ads.
It went offline when life got in the way. The tools here are a rebuild of that original idea, with a decade's worth of improvements — live weather data, hourly window analysis, pace adjustment science, and a clothing guide that actually accounts for wind chill and humidity, not just temperature.
The science behind the score
The run score is a weighted algorithm across four variables: temperature (the biggest factor, with an ideal band centered on 45–65°F), precipitation, humidity, and wind. Thunderstorms hard-cap the score at 15 regardless of everything else — there's no negotiating with lightning. The pace adjustment model is based on research from running physiologists, accounting for the thermoregulatory cost of heat and the reduced evaporative cooling efficiency in high humidity.
No algorithm replaces knowing your own body. The score is a starting point, not an instruction.
Milestones worth noting
- 1998Domain registered. First page: a hand-coded race report from a local 10K.
- 2004First version of the weather run calculator goes live. Runs on PHP + a static weather data file updated once daily.
- 2006Clothing recommendation engine added, mapping temperature bands to specific gear.
- 2008Hourly weather integration. The tool starts answering "when to run" not just "whether to run."
- 2014Site goes quiet. The calculator gets archived but not deleted.
- 2025Full rebuild. Live weather API, cartoon clothing figure, pace science, saved locations, history log.
What's here
Check today's conditions
Hopkinton is loaded by default. Boston Marathon start line weather, whenever you want it.
Privacy, briefly
No accounts. No tracking pixels. No ad networks. Weather lookups go directly from your browser to the Open-Meteo API — a free, open-source weather service. Saved locations and history are stored only in your browser's localStorage. Nothing is ever sent to a 26m server. See the full privacy page for details.
Contact
Questions, corrections, or run stories worth sharing: the contact is deliberately left off this page to avoid scrapers, but if you've been running long enough to find this site, you're resourceful enough to find the address. It's on the domain registration if nothing else.