howmuchsun

UV index and sunburn time in Poznań

UV peaks at 6.3 (high) in June, around 12:30 local time. At that intensity, untanned skin of type III burns in about 37 min.

How long before you burn?

Sunburn after 37 min unprotected, at peak UV in June
Peak UV index 6.3 High
With SPF 30 19 h if applied properly and reapplied

UV index month by month

Peak value on a representative day of each month, with burn time for skin type III.

MonthPeak UVCategoryPeak atBurns after
January 0.4 Low 12:30 523 min
February 1.1 Low 12:30 208 min
March 2.3 Low 12:30 101 min
April 4.0 Moderate 12:30 58 min
May 5.5 Moderate 12:30 43 min
June 6.3 High 12:30 37 min
July 6.2 High 12:30 37 min
August 5.3 Moderate 12:30 44 min
September 3.6 Moderate 12:30 65 min
October 1.8 Low 12:30 128 min
November 0.7 Low 11:30 333 min
December 0.3 Low 11:30 681 min

Burn time by skin type

At peak UV in June, with no sunscreen.

Fitzpatrick typeDescriptionBurns after
Type I Always burns, never tans 21 min
Type II Burns easily, tans minimally 27 min
Type III Burns moderately, tans gradually 37 min
Type IV Burns minimally, tans well 48 min
Type V Rarely burns, tans profusely 64 min
Type VI Never burns, deeply pigmented 106 min

UV through the day

UV index by month and hour in Europe/Warsaw local time, daylight saving included. Darker cells mean stronger UV.

UV index by month (rows) and local hour (columns). Each cell shows the rounded value; blank means zero.
Month456789101112131415161718192021
Jan
Feb 1 1 1 1 1
Mar 1 1 2 2 2 2 1 1
Apr 1 2 3 4 4 4 3 2 1 1
May 1 2 3 4 5 5 5 5 4 2 1
Jun 1 2 3 5 6 6 6 5 4 3 2 1
Jul 1 2 3 4 6 6 6 6 4 3 2 1
Aug 1 2 4 5 5 5 5 3 2 1
Sep 1 1 2 3 4 3 3 2 1
Oct 1 1 2 2 2 1 1
Nov 1 1 1
Dec

none strongest

Other cities in Poland

Assumptions

  • Clear sky. These are upper bounds. Cloud reduces UV, though less than people expect — you can burn on an overcast day.
  • No reflection. Snow roughly doubles your effective dose, and water and sand both add to it. None of that is modelled here.
  • Burn times are indicative. Published minimal erythemal doses vary by around 30% between studies, and individuals within a skin type vary more.
  • SPF assumes proper application. Most people apply a quarter of the amount used in testing, so real protection is far lower than the label.

Full methodology, sources and known limitations