Get Weather Data

Scripts for finding out the weather in a particular zip code on a particular day (or a set of dates). You can also find weather stations near a zip code, and vice-versa.

Background

From Bad Weather: Getting weather data by zip and date:

Some brief ground clearing before we begin. Weather data come from weather stations, which can belong to any of the five or more 'networks,' each of which collect somewhat different data, sometimes label the same data differently, and have different reporting protocols. The only geographic information that typically comes with weather stations is their latitude and longitude. By “weather”, we may mean temperature, rain, wind, snow, etc. and we may want data on these for every second, minute, hour, day, month etc. It is good to keep in mind that not all weather stations report data for all units of time, and there can be a fair bit of missing data. Getting data at coarse time units like day, month, etc. typically involves making some decisions about what particular statistic is the most useful. So for instance, you may want, minimum and maximum (for daily temperature), or totals (for rainfall and snow). With that primer, let’s begin.

We begin with what not to do. Do not use the NOAA web service. The API provides a straightforward way to get 'weather' data for a particular zip for a particular month. Except, the requests often return nothing. It isn't clear why. The documentation doesn't say whether the search for the closest weather station is limited to X kilometers because without that, one should have data for all zip codes and all dates. Nor does the API bother to return how far the weather station is from which it got the data, though one can get that post hoc using Google Geocoding API. However, given the possibility that the backend for the API would improve over time, here's an usage example :-

Usage

Usage: noaaweb-script.py [options] <input file>

Options:
-h, --help            show this help message and exit
-o OUTFILE, --outfile=OUTFILE
                    CSV Output file name (default: output.csv)

Example

NCDC Web service requires token to access, you'll get it from https://www.ncdc.noaa.gov/cdo-web/token.

You must set environment variable NCDC_TOKEN with the valid NCDC token, On Windows

set NCDC_TOKEN=<your NCDC token>

or On Linux

export NCDC_TOKEN=<your NCDC token>

noaaweb intput.csv

Sample input file

no,uniqid,zip,year,month,day
2000,1,7853,1999,12,15
2000,2,70503,1999,12,15
2000,3,38118,1999,12,26
2000,4,32548,1999,12,17
2000,5,7863,1999,12,17
2000,6,10705,1999,12,15
2000,7,80931,1999,12,19
2000,8,3878,1999,12,17
2000,9,17222,1999,12,16
2000,10,7831,1999,12,20
...

On to what can be done. The 'web service' that you can use is Farmer's Almanac's. Sleuthing using scripts that we discuss later reveal that The Almanac reports data from the NWS-USAF-NAVY stations (ftp link to the data file. And it appears to have data for most times though no information is provided on the weather station from which it got the data and the distance to the zip code.

If you intend to look for data from GHCND and ISD, there are two kinds of crosswalks that you can create – one that goes from zip codes to weather stations, and one that goes from weather stations to zip codes. I assume that we don’t have access to shape files (for census zip codes), and that postal zip codes encompass a geographic region. To create a weather station to zip code crosswalk, web service such as Geonames or Google Geocoding API can be used. If the station lat,./long. is in the zip code, the distance comes up as zero. Otherwise the distance is calculated as distance from the “centroid” of the zip code. For creating a zip code to weather station crosswalk, we get centroids of each zip using a web service such as Google (or use already provided centroids from free zip databases). And then find the 'nearest' weather stations by calculating distances to each of the weather stations. For a given set of zip codes, you can get a list of closest weather stations (you can choose to get n closest stations, or say all weather stations within x kilometers radius, and/or choose to get stations from particular network(s)) using the following usage example :-

Usage

Usage: zip2ws-script.py [options]

Options:
  -h, --help            show this help message and exit
  -D DATABASE, --database=DATABASE
                        Database name (default: zip2ws.sqlite)
  -i, --import          Create and import database
  -g, --geocode         Query and update Lat/Lon by Google Maps Geocoding API
  -c, --closest         Calculate and update closest table
  --ghcn=GHCN           Number of closest stations for GHCN (default: 3)
  --coop=COOP           Number of closest stations for COOP (default: 0)
  --usaf=USAF           Number of closest stations for USAF (default: 2)
  -d DISTANCE, --distance=DISTANCE
                        Maximum distance of stations from Zip location
                        (Default: 0)
  -e, --export          Export closest stations for each Zip to CSV file
  -o OUTFILE, --outfile=OUTFILE
                        CSV Output file name (default: F:\sandbox\gsood\get-
                        weather-data\get-weather-data\venv\lib\site-
                        packages\zip2ws\data\zip-stations.csv)
  --drop-closest        Drop closet table
  --clear-glatlon       Clear Google Maps Geocoding API Lat/Lon
  --use-zlatlon         Use Zip Lat/Lon instead of Google Geocoding Lat/Lon

Example

• Import zip codes and weather stations to database

  zip2ws -i
  

• Build closest weather station table for each zip code

  zip2ws -c
  

  It takes several minutes to process all zip codes

• Export closest stations for each zip codes to file

  zip2ws -e -o output.csv
  

The output lists for each zip code weather stations arranged by proximity. The task of getting weather data from the closest station is simple thereon – get data (on a particular set of columns of your choice) from the closest weather station from which the data are available. You can do that for a particular zip code and date (and date range) combination using the following usage example :-

To getting weather data there are two commands, one is the manager command (zipwd-manager) it will create a server process to dispatch job (list of zip codes and date range) to the workers process that will be create by another command (zipwd-worker) All workers will looking for weather data from thiers local database and put back the results to the manager process. We can have multiple workers run on same or difference machine also.

Usage

• Manager

  usage: zip2wd-manager-script.py [-h] [--config CONFIG] [-o OUTFILE] [-v]
                                  inputs [inputs ...]
  
  Weather search by ZIP (Manager)
  
  positional arguments:
    inputs                CSV input file(s) name
  
  optional arguments:
    -h, --help            show this help message and exit
    --config CONFIG       Default configuration file (default: zip2wd.cfg)
    -o OUTFILE, --out OUTFILE
                          Search results in CSV (default: output.csv)
    -v, --verbose         Verbose message
  

• Worker

  usage: zip2wd-worker-script.py [-h] [--config CONFIG] [-v]
  
  Weather search by ZIP (Worker)
  
  optional arguments:
    -h, --help       show this help message and exit
    --config CONFIG  Default configuration file (default: zip2wd.cfg)
    -v, --verbose    Verbose message
  

Configuration file

There are script settings in the configuration (zip2wd.cfg)

[manager]
ip = 127.0.0.1
port = 9999
authkey = 1234
batch_size = 10

[worker]
uses_sqlite = yes
processes = 4
nth = 0
distance = 30

[output]
columns = column-names.txt

[db]
zip2ws = zip2ws.sqlite
path = ./data/

• ip and port - IP address and port of manager process that the worker will be connect to.
• authkey - A shared password which is used to authenticate between manager and worker processes.
• batch_size - A number of zipcodes that manager process dispatch to worker process each time.
• uses_sqlite - Uses weather data from imported SQLite3 database if yes (recommend for speed) or download weather data for individual weather station on demand if no
• processes - A number of process will be forked on the worker process.
• nth - Search within n-th closest station [set to 0 for unlimited]
• distance - Search within distance (KM) [set to 0 for unlimited]
• column - A column file that contains list of weather data column to be output
• zip2ws - SQLite3 database of zip codes and weather stations
• path - Path relative to database files

Example

• Manager

  zip2wd-manager input.csv
  

• Worker

  zip2wd-worker
  

Authors

Suriyan Laohaprapanon and Gaurav Sood

License

Scripts are released under the MIT License.