# Precipitation anomaly (Chapel Hill 2 W, seven-day window) | PIER20 benchmarks

What does Precipitation anomaly (Chapel Hill 2 W, seven-day window) show?

Precipitation anomaly (Chapel Hill 2 W, seven-day window) is a source-faithful PIER20 calculation from NOAA/NCEI data. Scope: NOAA GHCN station Chapel Hill 2 W (GHCND:USC00311677), North Carolina. Each chart point covers the seven calendar days ending on that date; anomalies use 1991–2020 same-window normals. It follows the published eligibility, denominator, missing-value, revision and coverage rules in the Phase 1 computation contract.

As of **9 Aug 2026**, the latest reading is **56.06 mm**. That is down 10.70 mm over the past year and above its long-run median of -8.18 mm.

## Summary statistics (full history)

| Series | First | Latest | Min | Max |
|---|---|---|---|---|
| PIER20 calculation: Precipitation anomaly (Chapel Hill 2 W, seven-day window) | 38.22 | 56.06 | -52.60 | 240.13 |

## Last 24 readings

| Date | PIER20 calculation: Precipitation anomaly (Chapel Hill 2 W, seven-day window) |
|---|---|
| Jul 2026 | 52.98 |
| Jul 2026 | 53.17 |
| Jul 2026 | 55.72 |
| Jul 2026 | 28.33 |
| Jul 2026 | 4.42 |
| Jul 2026 | -11.52 |
| Jul 2026 | -11.67 |
| Jul 2026 | -12.95 |
| Jul 2026 | -13.77 |
| Jul 2026 | -14.98 |
| Jul 2026 | -16.60 |
| Jul 2026 | -4.04 |
| Jul 2026 | -3.89 |
| Jul 2026 | 40.60 |
| Jul 2026 | -12.49 |
| Aug 2026 | -20.81 |
| Aug 2026 | -24.27 |
| Aug 2026 | -22.53 |
| Aug 2026 | -15.96 |
| Aug 2026 | -10.83 |
| Aug 2026 | -4.71 |
| Aug 2026 | -2.53 |
| Aug 2026 | 1.44 |
| Aug 2026 | 56.06 |

## Frequently asked questions

**What is the current precipitation anomaly (Chapel Hill 2 W, seven-day window)?**

As of 9 Aug 2026, the latest reading is 56.06 mm. That is down 10.70 mm over the past year and above its long-run median of -8.18 mm.

**How often is this benchmark updated?**

This benchmark is built on daily data. The page is refreshed when the source publishes new observations; the freshness block below the chart shows the exact data-through date and when PIER20 last fetched the file.

**What data sources does this chart use?**

The chart is built from PIER20 calculation: Precipitation anomaly (Chapel Hill 2 W, seven-day window), sourced from NOAA/NCEI.

## Methodology

- Formula: current_cumulative_precipitation − normal
- Frequency: Daily
- Sources: PIER20 calculation: Precipitation anomaly (Chapel Hill 2 W, seven-day window) (NOAA-02) https://www.ncei.noaa.gov/cdo-web/webservices/v2. Data via NOAA/NCEI.
- Data through: 9 Aug 2026
- Last refreshed: 12 Aug 2026

Full interactive chart: https://pier20.com/benchmarks/phase1-noaa-02
Disclaimer: research software output, not investment advice.