PRISM ZIP Code → Zone Lookup

Overview

Purpose: Convert ZIP codes to USDA hardiness zones using authoritative PRISM 2023 data.

Why Bundled: No API calls needed, instant lookup, works offline.

Data Source

• URL: https://prism.oregonstate.edu/phzm/
• File: \phzm_us_zipcode_2023.csv\
• Size: ~2 MB (45,000 ZIP codes)
• Coverage: CONUS + Alaska + Hawaii + Puerto Rico
• Format: CSV (ZIP, zone, temp range)

Implementation

\\\`swift class ZoneLookupService { private var zipToZone: [String: String] = [:]

static let shared = ZoneLookupService()

func initialize() { guard let url = Bundle.main.url(forResource: “phzm_us_zipcode_2023”, withExtension: “csv”) else { return }

let lines = try? String(contentsOf: url).components(separatedBy: “\n”) for line in lines?.dropFirst() ?? [] { let parts = line.components(separatedBy: “,”) guard parts.count >= 2 else { continue } zipToZone[parts[0]] = parts[1] } }

func zone(forZIP zip: String) -> String? { return zipToZone[zip] } } \\\`

Token Efficiency

AI context: \"Zone: 7b"\ (2 tokens)
NOT: Full PRISM methodology explanation (100+ tokens)