/**
 * Service for interacting with NOAA NCEI (National Centers for Environmental Information)
 * Climate Data Online (CDO) API.
 *
 * Documentation: https://www.ncei.noaa.gov/support/access-data-service-api-user-documentation
 *
 * Provides official NOAA 1991–2020 climate normals for US locations. The CDO API is
 * station-based (not coordinate-based), so retrieval works in three steps:
 *   1. Find nearby stations that carry daily normals (`NORMAL_DLY`) for the coordinate.
 *   2. For the nearest qualifying station, read the daily high/low temperature normals
 *      (`DLY-TMAX-NORMAL`, `DLY-TMIN-NORMAL`) for the requested month/day.
 *   3. Read the monthly precipitation normal (`MLY-PRCP-NORMAL` from `NORMAL_MLY`) and
 *      divide by the number of days in the month to express an average daily value.
 *
 * Normals are keyed to a fixed reference year (2010) in the CDO dataset. Values are
 * requested with `units=standard` so temperatures come back in °F and precipitation in
 * inches. If no nearby station has complete normals, a DataNotFoundError is thrown so the
 * caller can fall back to Open-Meteo computed normals.
 */
import type { ClimateNormals } from '../types/openmeteo.js';
export interface NCEIServiceConfig {
    baseURL?: string;
    timeout?: number;
    token?: string;
}
/**
 * NCEI Climate Data Online (CDO) Service
 *
 * Provides access to official NOAA climate normals for US locations.
 * Requires API token (free from https://www.ncdc.noaa.gov/cdo-web/token)
 */
export declare class NCEIService {
    private client;
    private token;
    private cache;
    constructor(config?: NCEIServiceConfig);
    /**
     * Check if NCEI service is available (token configured)
     */
    isAvailable(): boolean;
    /**
     * Get official NOAA climate normals for a US location.
     *
     * @param latitude - Latitude (US only)
     * @param longitude - Longitude (US only)
     * @param month - Month (1-12)
     * @param day - Day of month (1-31)
     * @returns Climate normals sourced from NCEI
     * @throws {DataNotFoundError} - No token, or no nearby station with complete normals
     * @throws {RateLimitError} - CDO rate limit exceeded
     * @throws {ServiceUnavailableError} - CDO unavailable or invalid token
     */
    getClimateNormals(latitude: number, longitude: number, month: number, day: number): Promise<ClimateNormals>;
    /**
     * Find stations carrying daily normals near a coordinate, sorted by distance.
     * Expands the search extent once if the initial bounding box is empty.
     */
    private findNearbyStations;
    /**
     * Read daily high/low temperature normals (°F) for a station on a given date.
     * Returns null if either value is missing.
     */
    private fetchDailyTemperatureNormals;
    /**
     * Read the monthly precipitation normal (inches) for a station's month.
     * Returns null if the value is missing.
     */
    private fetchMonthlyPrecipitationNormal;
    /**
     * Handle API errors
     * @private
     */
    private handleError;
}
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