TEMIS -- Daily erythemal cloud-modified UV index for Germany

Daily cloud-modified erythemal UV index for Germany	UV archive overview
Clear-sky UV index: erythemal == regular archive maps & data Region: The Netherlands / Benelux \| Germany

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Date range:
16 Feb 2026
-- 12 Mar 2026

Introduction

The plots on this page show for selected places in Germany the UV index throughout the day, both cloud-free (thin blue line) and cloud-modified (red line/points) -- if the latter is absent, then cloud cover data is not available.

Today's cloud-modified UV index (available as of about 04:30 UTC) is updated when new cloud cover data arrives, which usually is every 15 minutes -- you may have to use shift-reload to see the latest images.

Data from 2024 has been reprocessed to provide some comparison.

[ basemap: Wikimedia ]

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Erythemal UV index of 10 March 2026
(click on image to enlarge)

	info: see below


download the full data : regular 0.25° netCDF file \| high-res 0.05° netCDF file
Map info: * Today's data: timeslice with the last available cloud data * Archive data: timeslice of 12:00 UTC * Map made using high-res 0.05° data * Range of colour bar is dynamic * Map ratio is not optimal * The block-like structures visible in particular in the high-res cloud-free maps during the low UV season in location where there may be snow is caused by the fact that the surface albedo climatology is given at the low-res 0.25° grid

Some info on the data file

The data file contains the cloud-free and cloud-modified UV index for an area covering Germany for each quarter of an hour from 03:00 UTC up to and including 21:45 UTC, both in the usual non-dimensional unit, and given with 3 decimals. For time steps with insufficient sunlight to determine UV index or cloud data or with missing cloud data, the entries have fill-values (-1.0).

The area that is covered by the data is:
> Germany: 5.50 – 15.50°E, 46.75 – 55.25°N

The original resolution of the data is the same as the standard UV grid: 0.25 by 0.25°. The line plots shown above are extracted from these data.

A version at higher resolution is made by interpolating the cloud-free data to 0.05 by 0.05° and then averaging the cloud data over 0.15 by 0.15° around the grid cell center. The difference in grid cell average surface elevation between the two resolutions is accounted for in the "hr" data for the Germany region.

The example maps on the right show the area of The Netherlands at (top) the original resolution of 0.25 by 0.25°, and (bottom) the higher resolution of 0.05 by 0.05°.

Most important global attributes:

data_product_date: date of the data in the file
date_created: date the data file was created
latest_cloud_modified_time: UTC time of the last time slice filled with cloud-modified UV index data
data_product_status: "near-real time" for the operational processing (as of 5 Dec. 2024) or "archive" for reprocessing data

Main data variables:
uvi_clear: Erythemal UV index cloud-free
uvi_cloudy: Erythemal UV index cloud-modified
status: Status of cloud-modified data:
0 = not available
1 = available for at least one grid cell
2 = forecast cloud data used (reserved flag)
plus grid cell coordinate & time data.

Data file(s) can be downloaded from the links provide above under the graph with the date in the filename. Today's data is also available with a static filename via:
> https://www.temis.nl/uvradiation/UVI/uviec_bx.nc: == 0.25 degree
> https://www.temis.nl/uvradiation/UVI/uviec_bx_hr.nc: == 0.05 degree

Cloud-free UV index The Netherlands 21 June 2024 at 12:00 UTC

Cloud-modified UV index The Netherlands 21 June 2024 at 12:00 UTC

Example plots of the cloud-free and cloud-modified UV index at 12:00 UTC for 21 June 2024 over The Netherlands at a resoltion of 0.25 by 0.25° (above) and 0.05 by 0.05° (below)

Daily cloud-modified erythemal UV index for Germany

Introduction

Erythemal UV index of 10 March 2026

Some info on the data file