Climate Indicators

Cooling Degree Days and Heating Degree Days

Cooling Degree Days (CDD) and Heating Degree Days (HDD) are a measure of energy demand for cooling and heating of buildings. They are defined as the number of degrees above or below a reference temperature. See the degree days tool for more information and charting of the available data.

GET /api/series/{slug}/hdd/

Return heating degree days for any location.

GET /api/series/{slug}/cdd/

Return cooling degree days for any location.

Example request:

GET /api/series/tasmax_day_HadGEM2-ES_rcp85/cdd/?g=POINT(-121.46+38.59)&freq=A HTTP/1.1
Host: api.cal-adapt.org
Accept: application/json

Example response:

HTTP/1.1 200 OK
Allow: GET, POST, OPTIONS
Content-Type: application/json
Vary: Accept

{
"data": [
    1272.4594726562,
    2066.6245117188,
    1458.0538330078,
    1674.4998779297
    ,
],
"index": [
    "2006-12-31T00:00:00Z",
    "2007-12-31T00:00:00Z",
    "2008-12-31T00:00:00Z",
    "2009-12-31T00:00:00Z",
    ,
]}
Parameters:
  • slug – series slug identifier, only valid for daily tasmax or tasmin slugs
Query Parameters:
 
  • g – a geometry (point, line, polygon) as GeoJSON, WKT, GML or KML
  • freq – resampling frequency string such as M, A, 10A, or any Pandas offset
  • thresh (float) – the reference temperature in F, defaults to 65

Extreme Heat, Heat Waves, and Warm Nights

An extreme heat day or warm night is defined as a day when the maximum/minimum temperature exceeds the 98th percentile of observed historical data from 1961–1990 between April and October. See the extreme heat tool for more information and charting of the available data.

GET /api/series/{slug}/exheat/

Return extreme heat, heat waves, or warm night counts for any location.

Example request:

GET /api/series/tasmax_day_HadGEM2-ES_rcp85/exheat/?g=POINT(-121.46+38.59) HTTP/1.1
Host: api.cal-adapt.org
Accept: application/json

Example response:

HTTP/1.1 200 OK
Allow: GET, POST, OPTIONS
Content-Type: application/json
Vary: Accept

{
"98p": 103.90999603271484,
"counts": {
    "2006-12-31T00:00:00+00:00": 1,
    "2007-12-31T00:00:00+00:00": 19,
    "2008-12-31T00:00:00+00:00": 3
    ,
}}
Parameters:
  • slug – series slug identifier, only valid for daily tasmax (extreme heat) or tasmin (warm night) slugs
Query Parameters:
 
  • g – a geometry (point, line, polygon) as GeoJSON, WKT, GML or KML
  • stat – one of max, mean, median, min, sum for spatial aggregation by polygon/line provided by the g param, defaults to mean
  • freq –

    resampling frequency string such as M, A, 10A, or any Pandas offset, defaults to A

  • pct (float) – percentile to use for extreme heat or warm night threshold, defaults to .98 (98th percentile) of observed data from 1961-1990 between April-October
  • duration (integer) – (duration of extreme event in days)

Extreme Precipitation

Extreme precipitation events can be characterized using Extreme Value Analysis (EVA) by return levels, including confidence intervals, using the peak over threshold methodology. See the extreme precipitation tool for more information and charting of the available data.

GET /api/series/{slug}/pot/

Response fields include returnlevels, threshold, and units (unit of measurement). The return levels are summarized over historic, mid, and end of century time frames. Each return interval is a 3-item array of the lower, estimated return level, and upper confidence interval.

Example request:

GET /api/series/pr_day_ACCESS1-0_rcp45/pot/?g=POINT(-121.4687+38.5938)&duration=2 HTTP/1.1
Host: api.cal-adapt.org
Accept: application/json

Example response:

HTTP/1.1 200 OK
Allow: GET, POST, OPTIONS
Content-Type: application/json
Vary: Accept

{
"returnlevels": {
    "1961-10-01:1990-09-30": {
        "10": [ 3.3738083898103706, 3.9522201904266527, 5.228567088406137 ],
        "100": [ 4.792120480767816, 6.491227596207121, 11.655569842787486 ],
        "2": [ 2.317027627106765, 2.5667466512434016, 2.941214643156155 ],
        "20": [ 3.781685742237907, 4.640839376130399, 6.677332244692823 ],
        "5": [ 2.9107509896073562, 3.321044449279986, 4.080450921786112 ],
        "50": [ 4.368586837537248, 5.648252163486491, 9.185085270172545 ],
        "n": 159
    },
    "2035-10-01:2064-09-30": {
        "10": [ 3.7262371212589867, 4.236568397086659, 5.240493845112521 ],
        "100": [ 4.906061402196474, 6.0225286812315595, 9.111781051084918 ],
        "2": [ 2.688362812028139, 2.9617466455337116, 3.315414408012187 ],
        "20": [ 4.134337164339881, 4.778850804514478, 6.252823005631932 ],
        "5": [ 3.312975478107658, 3.690233369085343, 4.342160397675551 ],
        "50": [ 4.571528643603971, 5.4895406091554895, 7.7864184564943955 ],
        "n": 175
    },
    "2070-10-01:2099-09-30": {
      "10": [ 4.241220088665857, 5.0994935705499715, 6.9916568467598665 ],
      "100": [ 6.244111144979032, 8.769602618538272, 16.754704790152964 ],
      "2": [ 2.820991602527356, 3.1581853987832025, 3.650831557730822 ],
      "20": [ 4.851689971070942, 6.081585627582591, 9.144602394922993 ],
      "5": [ 3.631161165606033, 4.209052130230058, 5.315306960831256 ],
      "50": [ 5.653315714995296, 7.536659927706938, 12.944282870291804 ],
      "n": 165
    },
    "threshold": 1.0,
},
"units": "inches"
}
Parameters:
  • slug – series slug identifier
Query Parameters:
 
  • g – a geometry (point, line, polygon) as GeoJSON, WKT, GML or KML
  • stat – one of max, mean, median, min, sum for spatial aggregation by polygon/line provided by the g param, defaults to mean
  • duration (integer) – duration of extreme event in days
  • intervals – comma separated list of return intervals, returns levels for 2, 5, 10, 20, 50, and 100 year events by default
  • pct (float) – percentile to use for exceedance threshold, when not specified the min value from the annual maxima series (AMS) is used