What is the weather usually like for the Leadville 100?

Short answer: plan for everything. Across the last 16 third Saturdays of August in Leadville, the average high was about 67°F and the average overnight low about 41°F, but the range runs from a 72°F scorcher (2020) to a 57°F soaker with three-quarters of an inch of rain (2022). Some precipitation fell on 12 of the 16 days, usually just a passing shower. Overnight lows dipped into the mid 30s°F in several years, and that's in town at 10,152 ft. On the high passes it is routinely 10 to 15 degrees colder with far stronger wind.

The Leadville Trail 100 events are traditionally held on mid-August weekends (in 2026, the MTB on August 15 and the Run on August 22). The table below shows town-level weather for the third Saturday of each August since 2010, from the ECMWF model record served by Open-Meteo's historical archive (ERA5 reanalysis through 2016, the 9 km IFS analysis from 2017 on). It is the closest thing to a "typical race day" record you can get without a crystal ball.

Third Saturday of August in Leadville, 2010 to 2025

Source: Open-Meteo's historical archive, modeled at Leadville's town coordinates and elevation; the record is ERA5 reanalysis through 2016 and the ECMWF 9 km IFS analysis from 2017 on (relabeled 2026-09-03; this page previously said ERA5 for every year). A model record smooths local extremes, so actual station readings on any given day can differ. Sky is the dominant daily weather condition.

When the rain actually falls, hour by hour, 2010 to 2025

Short answer: in the afternoon, and never before 11 AM. Across the last 16 race windows, 63 percent of all the precipitation that fell landed between noon and 6 PM, 26 percent between 6 PM and midnight, and just 8 percent in the whole morning from the 4 AM gun to noon. In none of the 16 years did any hour before 11 AM produce a measurable amount.

A daily rainfall total says nothing about when you get wet, and for a 30 hour race that is the only part that matters. This table takes the same hourly model record and clips it to the official Run window, 4:00 AM Saturday through 10:00 AM Sunday, then splits each year's precipitation into the four blocks a runner actually experiences. "Wet hours" counts hours reaching 0.005 inches. "First wet hour" is the first of them.

Share of all 16 years of race-window precipitation by block: 8.4 percent fell from the 4 AM gun to noon, 63.5 percent from noon to 6 PM, 26.2 percent from 6 PM to midnight, and 1.9 percent overnight into Sunday morning. Mean window total 0.065 inches. At least a hundredth of an inch fell in 9 of the 16 years, and 8 years produced no single hour reaching 0.005 inches at all. Source: the same ECMWF record via Open-Meteo at Leadville's town coordinates and elevation, generated 2026-08-24. A model analysis is not a rain gauge, and it smooths convective cells hard, so treat these as the pattern rather than as what any one runner felt. Free to cite with attribution. The 2026 row is included for comparison and is kept out of the cited 16 year totals so the figures people quote stay on 2010 to 2025. It comes from the same 9 km IFS analysis as every row from 2017 on. ERA5's own 25 km reanalysis, which became available for that weekend on Sep 3, gives a different answer for the same 30 hours, 0.233 inches with four wet hours from 5 PM; both figures and the two gauges are laid out in the verification section below.

Two things follow from this table. The first is that the shape of an afternoon-loaded wet race day is completely normal here, and a forecast that says dry until noon and then 90 percent is describing the climatology, not an anomaly. The second is the size. The wettest window in the record is 2022 at 0.70 inches, and the next wettest is 2016 at 0.10. Nothing else in 16 years exceeded a tenth of an inch. So when a forecast puts a quarter inch in the window, it is not describing a normal Leadville shower; it is describing the second wettest race day since 2010, and everything downstream of that, drop bag contents, crew shelter, how long a shell has to keep working, changes accordingly.

The same 30 hours at Hope Pass elevation, 2010 to 2025

Short answer: up high there is more water, it starts earlier, and it can be freezing. In the reanalysis grid cell containing Hope Pass, the 16 race windows from 2010 to 2025 carried 1.24 inches of precipitation against 1.04 in town, measurable amounts fell in 13 of the 16 years against 9 in town, and the town table's cleanest fact does not survive the climb: four of those years had a wet hour before noon at the pass, the earliest at 10 AM. The coldest hour in the record at that elevation is 29°F, and six of the 16 windows touched freezing or below.

The table above is town climatology, and the noon-to-6 percentages people quote from it are town numbers. But the exposed part of the course is not in town, so this table runs the identical 30 hour window against the model grid cell that contains Hope Pass, with temperature downscaled to the saddle's 12,548 ft. Same blocks, same 0.005 inch wet-hour threshold.

Share of the 16 years of window precipitation by block at the Hope Pass cell: 15.4 percent from the 4 AM gun to noon (nearly double the town share), 71.8 percent from noon to 6 PM, 12.5 percent from 6 PM to midnight, 0.3 percent overnight. Mean window total 0.077 inches. At least a hundredth of an inch fell in 13 of 16 years; only 4 years produced no wet hour at all. Source: the same ECMWF record via Open-Meteo at the grid cell containing Hope Pass, generated 2026-08-27. Two limits matter more here than in town. Precipitation is the average over a model cell, not a gauge on the saddle, and a cell smooths a narrow ridgeline hard, so single-storm extremes will be worse than these numbers. And the temperatures are downscaled to 12,548 ft from that same smoothed cell; the wind that makes 29°F dangerous is not in this table at all. Free to cite with attribution. The 2026 row comes from the same 9 km IFS analysis as every row from 2017 on and is kept out of the cited 16 year figures. ERA5's 25 km reanalysis for the same window at this cell gives 0.126 inches with three wet hours from 5 PM and a 36 F minimum; see the verification section.

What changes against the town table. First, the morning is not clean at elevation: 2017, 2018, 2021 and 2022 all produced a measurable hour before noon at the pass, where town has never done so in the record, so "dry until 11" is a town fact, not a course fact. Second, the years stack differently: 2022 is still the outlier at 0.51 inches, but 2025 at 0.26 and 2018 at 0.11 both exceed anything town recorded outside 2022, meaning the pass has had three windows in the last nine years wetter than all but one town window in sixteen. Third, and the one that should drive drop-bag decisions: the two wettest Hope Pass windows in the record, 2021 and 2022, are also the two coldest at 29°F. Wet and freezing arrive together up there. That combination has never once appeared in the town record, and it is the difference between a shower and a hypothermia problem.

How the 2026 race-day forecast actually did

Short answer: The 90 percent was right, the timing was right, and on both gauges the amount was about two and a half times too much. Every source agreed the morning would be dry and it was. What accumulation the nearest station measured arrived in the evening, which is where the forecast put most of it. The quarter inch never showed up at either gauge; of the two model records, one says a tenth of that and the other says the quarter inch fell.

Below is what this site's brief carried before the gun on 2026-08-22, next to four independent records of what fell across the official 4:00 AM Saturday August 22 through 10:00 AM Sunday August 23, the official 30 hour Leadville Trail 100 Run window.

What was forecast

What actually fell

Limits on each record, because they are not interchangeable. KLXV automated station, Leadville Lake County Airport: This station reports an hourly precipitation figure only intermittently, so 0.09 inches is a floor for the day and not a complete total. Fremont Pass SNOTEL 485:CO:SNTL: The gauge sits about 27 miles north northeast of Hope Pass, in Summit County at the head of the valley, so it measures the same air mass rather than the same storm cell. ECMWF IFS analysis, town grid box (9 km): A model analysis runs on a grid kilometres across and smooths convective cells hard. A thunderstorm standing over one drainage can leave almost no trace in it. ERA5 reanalysis, town grid box (25 km): A coarser grid than the IFS analysis and a different assimilation; the two model records disagree by a factor of ten on the same 30 hours, which is a measure of how little either resolves a single storm. Final ERA5 replaces the early-release version about three months after the fact.

The scorecard

What the forecast got right:

• It rained. A 90 percent forecast on a day that produced measurable rain at two independent gauges is a hit, not a miss.
• The morning stayed dry. Nothing measurable fell before noon in any of the four records, which is what the site told runners for four days and what the 16 year climatology says happens every year.
• The shape held. Every hundredth of an inch the airport actually measured arrived after 6 PM, which is where the forecast put roughly three quarters of the day's water, and ERA5 puts 0.209 of its 0.233 inches in the same block.
• The cold was right. Hope Pass was forecast at 41 to 42 F from 9 PM; the IFS analysis grid there bottomed out at 40 F and ERA5 at 36 F.

What it got wrong:

• On the gauges, the volume was over-forecast by roughly a factor of two and a half. Both authorities landed on about 0.24 inches. The elevation gauge measured 0.10 and the airport reported at least 0.09. The IFS analysis says less still, 0.020. ERA5 alone says 0.233, almost exactly the forecast; it is one model record against two gauges and another model.
• This site said on Aug 20 that a quarter inch would make 2026 the second wettest race window since 2010 by a wide margin. On the gauges and on the table's own model record, 2026 instead sits in the dry half of the 17 year record. On ERA5 it would rank second behind 2022. The table keeps the IFS figure because that is the record every row since 2017 is built from.

What nobody can tell you from these records: Nothing here settles what fell on Hope Pass. No gauge sits on the course, the nearest one at elevation is about 27 miles away at the head of the valley, and the reanalysis grid box that covers the pass is too coarse to resolve a single cell. Runners who were up there between 1 PM and 6 PM know something these three records do not.

Temperature came out closer than volume, which is the usual pattern and the more consequential one at 12,500 ft. Hope Pass was forecast at 41 to 42 F from 9 PM and the model grids there bottomed out at 40 F in the IFS analysis and 36 F in ERA5, the Hope Pass grid minimums across the window. In town the zone forecast called for 68 to 80 F and the day delivered 75 F high, 43 F low in both model records for the town grid box; the airport read 75 F at 2 PM. A precipitation forecast that runs high and a temperature forecast that lands is a good argument for packing to the temperature and treating the rain percentage as a probability rather than a promise.

Verification assembled 2026-08-24, model records re-read 2026-09-03 from the KLXV observation archive at api.weather.gov, the USDA NRCS daily record for Fremont Pass SNOTEL, and two ECMWF model records via Open-Meteo, the 9 km IFS analysis and the 25 km ERA5 reanalysis, the latter read on 2026-09-03 once it covered the weekend. The forecast figures are quoted from this site's own published brief for that morning, not reconstructed after the fact. Free to cite with attribution.

What this means if you're racing or crewing

Three patterns show up in this table. First, mornings are cold: a 4 AM start under a 35 to 45°F sky is the norm, and hypothermia DNFs at Leadville are historically more common than heat problems. Second, some rain falls more Augusts than not, typically as brief afternoon showers rather than all-day events, but 2022 shows the exception that catches people out. Third, wind gusts of 20 to 35 mph appear in most years, and what registers as 25 mph in town is far worse on Sugarloaf or Hope Pass. Layers, real rain gear in drop bags, and a warm-clothes plan for your crew stops cover the realistic range.

For today's actual conditions and this week's forecast, see the live dashboard. For how the altitude itself will treat you, start with the acclimatization guide, or the race-week arrival timing guide if you are coming in for the 100. Crews planning around this weather should see the crew resource index.