skill / Site Planning

Environmental Analysis

A Claude Code skill that researches climate and environmental conditions for any site — temperature, precipitation, wind patterns, sun angles, flood zones, seismic risk, soil, and topography using authoritative public data sources.

site-planning research
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What it does

Type /environmental-analysis with an address. Claude searches authoritative public data sources and produces a structured environmental analysis covering climate, natural features, and hazards. Each section is researched independently with 1–3 targeted searches.

Install

Claude Desktop:

  1. Open Customize → Browse plugins
  2. Click + → Add marketplace from GitHub
  3. Enter AlpacaLabsLLC/skills-for-architects
  4. Install the Site Planning plugin

Claude Code (terminal):

claude install github:AlpacaLabsLLC/skills-for-architects/01-site-planning

Usage

/environmental-analysis 250 Hudson St, New York NY

What it researches

Climate

  • Temperature ranges (annual, seasonal, design day)
  • Precipitation (annual totals, snow, rain patterns)
  • Prevailing wind (direction, speed by season)
  • Sun angles (altitude at solstices and equinoxes)
  • ASHRAE climate zone and Köppen classification
  • Heating and cooling design temperatures

Natural features & hazards

  • Topography and elevation
  • Flood zones (FEMA maps)
  • Seismic risk (USGS hazard data)
  • Soil conditions (NRCS web soil survey)
  • Vegetation and water bodies
  • Environmental contamination (EPA Superfund, brownfields)

Data sources

  • NOAA Climate Normals
  • National Weather Service
  • NOAA Solar Calculator
  • DOE Building Energy Codes
  • NREL Solar Resource
  • FEMA Flood Map Service
  • USGS Earthquake Hazards
  • USGS National Map
  • NRCS Web Soil Survey
  • EPA Superfund/Brownfields
  • NWI Wetlands Mapper

Sample output

Generated from: /environmental-analysis 250 Hudson St, New York NY

# Environmental Analysis — 250 Hudson St, New York, NY

> **Date:** 2026-03-16 | **Coordinates:** 40.7267°N, 74.0076°W

## Key Metrics

| Metric | Value |
|--------|-------|
| Climate zone | ASHRAE 4A (Mixed-Humid) |
| Köppen classification | Cfa (Humid Subtropical) |
| Annual precipitation | 49.9 in (1,268 mm) |
| Heating design temp (99%) | 14°F (−10°C) |
| Cooling design temp (1%) | 92°F (33°C) |
| Flood zone | Zone X (Minimal Risk) |
| Seismic risk | Moderate (SDC B) |
| Elevation | ~20 ft (6 m) above sea level |

---

## 1. Climate

### Temperature

| Month | Avg High (°F) | Avg Low (°F) |
|-------|---------------|-------------|
| January | 39 | 27 |
| February | 42 | 29 |
| March | 50 | 35 |
| April | 62 | 45 |
| May | 72 | 55 |
| June | 81 | 64 |
| July | 86 | 70 |
| August | 84 | 69 |
| September | 77 | 62 |
| October | 65 | 51 |
| November | 54 | 41 |
| December | 43 | 32 |

- **Annual mean temperature:** 56.5°F (13.6°C)
- **Record high:** 106°F (41°C), July 9, 1936
- **Record low:** −15°F (−26°C), February 9, 1934
- **Frost-free season:** approximately mid-April to mid-November (~210 days)

*Source: NOAA 1991–2020 Climate Normals, Central Park station (USW00094728)*

### Precipitation

| Season | Precipitation (in) |
|--------|-------------------|
| Winter (Dec–Feb) | 11.0 |
| Spring (Mar–May) | 12.5 |
| Summer (Jun–Aug) | 13.5 |
| Fall (Sep–Nov) | 12.9 |
| **Annual total** | **49.9** |

- **Annual snowfall:** 29.8 in (76 cm)
- **Wettest month:** July (4.6 in)
- **Driest month:** February (3.1 in)
- Precipitation is distributed relatively evenly across the year with a slight
  summer peak from convective storms.

*Source: NOAA 1991–2020 Climate Normals, Central Park*

### Prevailing Winds

| Season | Prevailing Direction | Avg Speed |
|--------|---------------------|-----------|
| Winter | NW | 11–12 mph |
| Spring | NW to S (variable) | 10–11 mph |
| Summer | S to SW | 8–9 mph |
| Fall | NW | 9–10 mph |

- **Annual average wind speed:** ~9.5 mph (Central Park)
- Winter brings the strongest and most persistent winds from the northwest
  (cold continental air). Summer winds shift to southerly, bringing humid
  maritime air from the Atlantic.
- Street-level winds in Hudson Square are channeled by the north-south street
  grid. The Hudson River corridor to the west amplifies westerly gusts.

*Source: NOAA/NWS, Central Park ASOS station*

### Sun Angles

Solar altitude at solar noon (40.73°N latitude):

| Date | Solar Altitude | Sunrise Azimuth | Sunset Azimuth |
|------|---------------|-----------------|----------------|
| Summer solstice (Jun 21) | 72.8° | 58° (ENE) | 302° (WNW) |
| Equinoxes (Mar/Sep 21) | 49.3° | 90° (E) | 270° (W) |
| Winter solstice (Dec 21) | 25.9° | 122° (ESE) | 238° (WSW) |

- **Longest day:** ~15 hours 6 minutes (June 21)
- **Shortest day:** ~9 hours 15 minutes (December 21)
- The low winter sun angle (25.9°) means significant shadowing from the
  6–12 story buildings in Hudson Square, particularly on north-facing
  facades and narrow east-west streets.

*Source: NOAA Solar Calculator (gml.noaa.gov/grad/solcalc/)*

### Design Temperatures

| Parameter | Value |
|-----------|-------|
| Heating 99.6% | 11°F (−12°C) |
| Heating 99% | 14°F (−10°C) |
| Cooling 0.4% | 94°F (34°C) |
| Cooling 1% | 92°F (33°C) |
| Cooling wet bulb (1%) | 75°F (24°C) |
| HDD (base 65°F) | ~4,700 |
| CDD (base 65°F) | ~1,100 |

*Source: ASHRAE Handbook of Fundamentals, Central Park station*

---

## 2. Natural Features & Hazards

### Topography

- **Elevation:** approximately 20 ft (6 m) above sea level
- **Terrain:** flat, urban fill over original Manhattan shoreline
- The site is on the western edge of lower Manhattan, approximately 2 blocks
  east of the Hudson River. The original Manhattan shoreline was roughly at
  Greenwich Street — the land west of that (including portions of Hudson
  Street) is largely landfill placed in the 18th and 19th centuries.

*Source: USGS National Map*

### Flood Zones

- **FEMA designation:** Zone X (area of minimal flood hazard)
- The site at 250 Hudson St is outside the current 100-year and 500-year
  floodplains.
- However, the Hudson River waterfront 2 blocks to the west is in
  **Zone AE** (1% annual chance of flooding). The NYC Panel on Climate
  Change projects increased coastal storm surge and sea level rise that
  could extend flood risk inland.
- The nearest significant flood zone boundary runs along West Street /
  Route 9A.

*Source: FEMA Flood Map Service Center (msc.fema.gov), FIRM panel 3604970163F*

### Seismic Risk

- **Seismic Design Category:** B (per ASCE 7-22)
- **Mapped spectral acceleration (Ss):** 0.26g (short period)
- **Mapped spectral acceleration (S1):** 0.07g (1-second period)
- **Peak Ground Acceleration (PGA):** ~0.08g (2% in 50 years)
- New York City is in a region of moderate seismic risk. The Ramapo Fault
  system is located approximately 25 miles northwest. Historical earthquakes
  in the region have reached magnitude 5.0+, but damaging events are
  infrequent.

*Source: USGS Earthquake Hazards Program*

### Soil Conditions

- **Bedrock type:** Hartland Formation — migmatitic schist, gneiss,
  granofels, and amphibolite (metamorphic)
- **Depth to bedrock:** Variable. Lower Manhattan generally has bedrock at
  80–150+ ft in the Hudson Square area, with deep glacial and fill deposits.
  This contrasts with Midtown, where bedrock is sometimes <30 ft deep.
- **Overburden:** Glacial till, outwash deposits, and urban fill. The fill
  near the Hudson River includes historic construction debris and organic
  material.
- **Groundwater:** Shallow groundwater table expected given proximity to
  the Hudson River, likely within 10–15 ft of surface.

*Source: USGS Data Report 1176; NRCS Web Soil Survey*

### Vegetation

- The site is fully urbanized with no significant natural vegetation.
- Street trees (London Plane and Honey Locust) along Hudson Street.
- Hudson River Park, a 5-mile linear waterfront park, is 2 blocks west.
- No protected species or critical habitats identified.

### Water Bodies

- **Hudson River:** approximately 800 ft (240 m) to the west
- **No wetlands** at the site (fully urbanized)

*Source: USFWS National Wetlands Inventory*

### Environmental Contamination

- The site is not listed as a Superfund site.
- **Hudson River PCBs Superfund Site:** The Hudson River is a federally
  designated Superfund site due to PCB contamination (General Electric,
  Hudson Falls). This applies to the river itself, not adjacent properties.
- Lower Manhattan has a history of industrial use (printing, manufacturing,
  warehousing) that may have left localized contamination. Phase I and
  Phase II Environmental Site Assessments are recommended.
- No active brownfield cleanup sites identified at 250 Hudson St.

*Source: EPA Superfund site search, EPA NEPAssist*

---

## Sources

1. NOAA 1991–2020 Climate Normals, Central Park
2. NOAA Solar Calculator
3. ASHRAE Climatic Design Conditions
4. DOE Building Energy Codes, Climate Zones
5. FEMA Flood Map Service Center
6. NYC Flood Hazard Mapper
7. USGS Earthquake Hazards, Design Maps
8. USGS Data Report 1176, Bedrock-Surface Elevation, NYC
9. NRCS Web Soil Survey
10. USFWS National Wetlands Inventory
11. EPA Superfund Site Search
12. NCEI U.S. Wind Climatology

## Gaps & Caveats

- Wind data is from Central Park — street-level conditions at 250 Hudson St
  will differ due to urban canyon effects and the Hudson River corridor.
- Soil and bedrock depth are estimated from USGS borough-wide mapping.
  A site-specific geotechnical investigation is necessary for foundation design.
- Flood zone is based on current FEMA FIRMs. Preliminary maps may reclassify
  adjacent areas. Climate projections suggest increased risk by mid-century.
- Environmental screening uses federal databases only. NYC DEP, NYS DEC, and
  NYC OER records should also be checked. A Phase I ESA is recommended.
- Groundwater depth is estimated; dewatering may be required for
  below-grade construction.
- Snow load not included; consult ASCE 7 (NYC: 30 psf).