TODAY FEB25
TEMPERATURE25
HUMIDITY100
PRESSURE30.26
WIND COND.250 5.4
  • 3416Thu
  • 3727Fri70%
  • 3822Sat20%
  • 3012Sun
  • 2712Mon
daynightWeather update from Decorah at

Key findings

  • The highest monthly average temperature in Castalia for July is 73 degrees
  • The lowest monthly average temperature in Castalia for January is 19 degrees
  • The most monthly precipitation in Castalia occurs in June with 4.3 inches
  • The air quality index in Castalia is 30% better than the national average
  • The pollution index in Castalia is 90% better than the national average

Compare Castalia, IA Weather

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      Castalia Average Temperature

      In the event that the weather data was unavailable for this city, estimates based upon nearby cities were used.
      MonthTemp. (min)Temp. (max)Temp. (avg)Precipitation
      January13°F27°F19°F0.5"
      February14°F29°F21°F0.4"
      March29°F45°F36°F1.5"
      April40°F59°F48°F3.4"
      May50°F70°F60°F2.9"
      June61°F79°F69°F4.3"
      July65°F82°F73°F3.9"
      August62°F79°F70°F4.0"
      September54°F73°F63°F3.4"
      October43°F61°F51°F3.0"
      November31°F47°F38°F1.0"
      December18°F31°F24°F0.9"

      Castalia air quality index & pollution index

      In the event that the air quality/pollution data was unavailable for this city, estimates based upon nearby cities were used.
      IndexCastaliaIowaNational
      Air quality index353950
      Pollution index530,4841,643,8365,066,862

      Castalia air quality information

      MeasurementTotal
      Days measured365
      Days with good air quality310
      Days with moderate air quality55
      Days w/ poor A.Q. for sensitive groups0
      Days with unhealthy air quality0

      Castalia air quality information

      PollutantTotal
      Arsenic0.000%
      Benzene0.010%
      Carbon Tetrachloride0.001%
      Lead0.002%
      Mercury0.000%

      Average monthly Castalia temperature with heat index

      Castalia monthly precipitation with daily maximum

      Castalia monthly snow depth with daily maximum

      Castalia monthly wind speed information

      Nearby cities with good air quality

      City, StatePopulationAir Quality IndexNational Avg.
      St. Olaf, IA1382942%
      Monona, IA1,4952942%
      Postville, IA2,2813530%
      Waukon, IA3,7863530%
      Luana, IA3383530%
      Castalia, IA1883530%

      Cities with similar population

      City, StatePopulationAir Quality IndexNational Avg.
      Cascadia, OR1882844%
      Morganville, KS1883236%
      Bienville, LA1883922%
      Moorefield, AR1884510%
      Gantt, AL1883530%
      Castalia, IA1883530%
      Source: The Castalia, IA weather data displayed above is derived from the NOAA (National Oceanic and Atmospheric). Air quality and pollution data is derived from the EPA (United States Environmental Protection Agency). Air quality and pollution levels measured in a particular area may not be representative of the entire county.