# Growing-degree days (Chapel Hill 2 W, seven-day window) | PIER20 benchmarks

What does Growing-degree days (Chapel Hill 2 W, seven-day window) show?

Growing-degree days (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 **117.25 degree-days**. That is up 52.3% over the past year and above its long-run median of 47.80 degree-days.

## Summary statistics (full history)

| Series | First | Latest | Min | Max |
|---|---|---|---|---|
| PIER20 calculation: Growing-degree days (Chapel Hill 2 W, seven-day window) | 0.00 | 117.25 | 0.00 | 137.00 |

## Last 24 readings

| Date | PIER20 calculation: Growing-degree days (Chapel Hill 2 W, seven-day window) |
|---|---|
| Jul 2026 | 136.20 |
| Jul 2026 | 134.55 |
| Jul 2026 | 132.05 |
| Jul 2026 | 128.45 |
| Jul 2026 | 123.45 |
| Jul 2026 | 119.00 |
| Jul 2026 | 116.20 |
| Jul 2026 | 115.90 |
| Jul 2026 | 117.55 |
| Jul 2026 | 120.05 |
| Jul 2026 | 123.40 |
| Jul 2026 | 126.20 |
| Jul 2026 | 130.10 |
| Jul 2026 | 131.45 |
| Jul 2026 | 95.80 |
| Aug 2026 | 98.65 |
| Aug 2026 | 104.25 |
| Aug 2026 | 107.60 |
| Aug 2026 | 108.95 |
| Aug 2026 | 108.35 |
| Aug 2026 | 110.30 |
| Aug 2026 | 113.65 |
| Aug 2026 | 116.40 |
| Aug 2026 | 117.25 |

## Frequently asked questions

**What is the current growing-degree days (Chapel Hill 2 W, seven-day window)?**

As of 9 Aug 2026, the latest reading is 117.25 degree-days. That is up 52.3% over the past year and above its long-run median of 47.80 degree-days.

**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: Growing-degree days (Chapel Hill 2 W, seven-day window), sourced from NOAA/NCEI.

## Methodology

- Formula: sum(max(0, min(Tmean, 30°C) − 10°C))
- Frequency: Daily
- Sources: PIER20 calculation: Growing-degree days (Chapel Hill 2 W, seven-day window) (NOAA-11) 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-11
Disclaimer: research software output, not investment advice.