Noah Jacob @PreconPro

The industry just hasn’t called it out yet. I will.

Flat weather contingency in construction estimation is a horrible idea.

The job that buried your margin last winter didn’t lose money because of bad weather. It lost money because you priced weather like it was 1987.

Your competitor who runs NOAA historical data before pricing? They’re not smarter than you. They just stopped pretending that gut feel is a risk model.

Guessing 3% on every bid regardless of season, location, or trade sequence isn’t conservative. It’s lazy math dressed up as experience.

Full breakdown — heat thresholds, storm season, Gulf season, freeze tail risk, and a month-by-month Texas risk calendar: xyloclime.com/blog/texas-con…

Texas estimators: a flat weather contingency on a Texas bid is usually wrong in two directions at once. Here’s the breakdown 🧵

We modeled a 240-day Houston site work scope recently. Simple 30-year average: 31 non-workable days Recency-weighted P80: 52 non-workable days That’s 21 extra days. At $15-20K/day — that’s $300K+ in unpriced exposure on one scope.

The mistake most estimates make: treating heat as a shutdown event. A crew working 6-hour days in a Houston July doesn’t show up as a weather day in your logs. But they’re delivering 25-40% less output than your schedule assumes. That compounds fast.

Texas isn’t one climate — it’s four. Gulf Coast, DFW, West Texas, South Texas all have completely different risk profiles. What works in Houston will underprice a Panhandle job and overprice a San Antonio job.

Alternate link if the first doesn’t work xyloclime.com/blog/how-to-ac…

When you bring actual workable-day counts and P50/P80 ranges to a bid, the conversation with the owner changes. You’re not defending a contingency. You’re presenting data. Full breakdown with visuals here: xyloclime.com/blog/how-to-ac…

Most weather contingencies in construction bids are wrong. Not because estimators are careless — because gut feel calibrates to memorable years, not actual historical distributions. Here’s how to price weather risk properly:

The framework in short: 1.Identify your weather-sensitive activities (earthwork, concrete, envelope) 2.Pull historical data for the actual months your schedule occupies 3.Apply recency weighting 4.Evaluate P50 + P80 by phase 5.Separate shutdown days from productivity

One thing most estimators miss even when they do pull historical data: A wet year from 2005 shouldn’t weigh the same as 2023. Climate baselines drift. Recency weighting corrects for that — recent years are more predictive than a flat 30-year average.

A real example: 180-day earthwork scope, DFW, Oct–March Simple 30-yr average: 22 non-workable days budgeted Recency-weighted P50: 28 days Recency-weighted P80: 36 days That 14-day gap at $18–22k/crew day = $250–300k in unpriced exposure. That’s not a margin of error. That’s a gap

Weather risk isn’t a single number. It’s a range with a shape. P50 = what a typical year looks like P80 = worse than 80% of historical years (~1 in 5) P90 = near-worst case The gap between P50 and P80 is your actual contingency range. Most bids never calculate it.

I built a tool that does this automatically. 👉 xyloclime.com — 7 day free trial, no charge until day 8.

The contractors starting to use it are showing up to owner presentations with a defensible, data-backed number. That’s a different kind of proposal.

Most GCs bid weather contingency the same way they did 20 years ago. Pick a number. Hope for the best.