Climate Data API
Part of the Foreca Weather API: tell your users whether today is warmer or colder than usual, and what weather to expect in any month of the year.
Monthly and daily climate normals for 1991–2020
Temperature, precipitation, rain days, frost days and sea temperature
Included in the Cirrus plan · free 30-day trial
Built for apps that put weather in context
Climate normals answer the questions your users ask beyond the forecast.
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Weather apps: add a climate view with average temperatures and rainfall for every month, so users see what is typical where they live.
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Travel apps: help users pick the best time to visit with monthly temperatures, rain days and sea temperature for each destination.
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Gardening and outdoor apps: help users plan planting and outdoor work around frost days and monthly rainfall.
Climate Data API at a glance
The Cirrus plan includes Climate Data API. Explore the included features below.
Monthly normals
Average, minimum and maximum temperature, precipitation, rain days, frost days and sea surface temperature for each month.
Daily normals
Average, minimum and maximum temperature for any day of the year.
Reference period
30-year averages for 1991–2020.
Coverage
Worldwide, for any coordinate, including seas and Antarctica.
Resolution
About 25 km for temperature and precipitation, 5 km for rain days and sea temperature, and 50 km for frost days. In the United States, about 4 km for high and low temperature, precipitation and rain days.
Method
Foreca-processed 30-year averages of gridded climate datasets.
Units
Temperature in Celsius or Fahrenheit. Precipitation in millimetres.
Format
REST API, JSON. Query by coordinates or Foreca location ID.
How your app gets the data
Your app asks for the month or the day it needs. One monthly call returns all twelve months, enough for a full climate chart. For a daily comparison, ask for today's date and show the normal next to the forecast.
What it works best for
Answering "is this normal?" Climate Data describes the typical weather for a place and a time of year, not what happened on a given day. For past observations, see Historical Weather.
Combine with point forecasts
Put the daily normal next to the forecast so your users see at a glance whether tomorrow will be warmer or colder than usual. Point Forecasts is included in every Foreca Weather API plan.
What the climate values mean
Example: the 1991–2020 normals for central Helsinki from the API, rounded to one decimal.
Monthly normals for Helsinki, January
| Value | Helsinki, January | What it means |
|---|---|---|
| Average daily high | −0.3 °C | Average of the daily maximum temperatures in the month. |
| Average daily low | −5.8 °C | Average of the daily minimum temperatures in the month. |
| Average temperature | −3.0 °C | Average temperature over the whole day. |
| Precipitation | 58.6 mm | Total precipitation in the month. |
| Daily precipitation | 1.9 mm | Monthly total divided by the number of days in the month. |
| Rain days | 20.2 | Days with at least 0.1 mm of precipitation. |
| Frost days | 28.2 | Days with a low temperature below 0 °C. |
| Sea temperature | 0.9 °C | Average sea surface temperature. Seas and coasts only. |
| Value | Helsinki, 15 July |
|---|---|
| Average low | 14.1 °C |
| Average temperature | 17.5 °C |
| Average high | 20.2 °C |
Climate Data API FAQ
How are the daily normals calculated?
As 15-day central moving averages of the 30-year daily averages for 1991–2020. This smooths out single unusual days, so the normal changes gradually from one day to the next.
Do the daily normals include precipitation?
No. Daily normals cover the average, minimum and maximum temperature. Precipitation, rain days and frost days are available as monthly normals.
Do the normals come from the nearest weather station?
No. They come from gridded climate data, not single stations, so two nearby locations can get slightly different values.
Why do frost days look different near mountains or the coast?
Frost days come from a coarser grid than temperatures. Near mountains the number can be higher than the location's low temperature suggests. At sea, in Antarctica and at some coastal points, such as central Barcelona, there is no frost day value.
Why is sea temperature empty for my location?
Sea surface temperature is given at sea and up to about 5–15 km from the coast. Further inland the value is null, and lakes do not get a value, with the Caspian Sea as the exception. On frozen sea the value is about −1.8 °C.
Is there a climate map layer?
No. Climate Data is point data for a location. Weather Maps has forecast and observation layers, such as temperature, but no climate normal layers.
Can I store the climate normals in my app?
Yes, for as long as your agreement is valid. The normals change only when Foreca renews the dataset, last in 2024, and storing them saves calls from your daily quota.
Start building with climate data
The Climate Data documentation describes the monthly and daily endpoints and their parameters. For forecast and radar maps, see the weather map layers.
Try it first: the 30-day free trial includes Climate Data for a sample area in northern Spain and southern France, with 2,000 requests a day and no credit card.