Portsmouth Rhode Island Weather Almanac
Friday, December 18, 2020
Cloudy to Clear PM, Continued Cold
Climate Normal Period Climate Record Period  
1981- 2010   1893 - 2020  
    December 18, 2020     Record Record
Observed Daily Data   Observed   2019   Normal   Depart   Highest Lowest
Maximum Temperature   29   37   41   -12   60   in 1984   11   in 1919  
Minimum Temperature   22   22   27   -5   47   in 1996   -3   in 1919  
Average Temperature   26   30   34   -8   50   in 2012   4   in 1919  
Precipitation   .00   .01   .14   -.14   1.46   in 1954            
One Hour   .00   .00           .44   in 1954            
Snow   0.0   0.1   0.3   -0.3   6.6   in 1904            
Snow Depth   7   T           12   in 1904            
HDD   39   35   31   +8   61   in 1919   15   in 2012  
CDD   0   0   0   +0   0   in   0   in    
Maximum Dew Point   20   29   33   -13   54   in 2016   4   in 2009  
Minimum Dew Point   13   11   17   -4   47   in 1996   -10   in 1979  
Average  Dew Point   17   20   25   -8   50   in 1996   -1   in 1979  
Maximum Humidity   88%   95%   84%   +4%   100%   in 2017   51%   in 1978  
Minimum Humidity   56%   62%   54%   +2%   96%   in 1996   26%   in 2002  
Average Humidity   72%   79%   69%   +3%   98%   in 1996   43%   in 1978  
Maximum Barometer   30.31   29.87   30.14   +00.17   30.59   in 1957   29.59   in 2001  
Minimum Barometer   30.08   29.62   29.80   +00.28   30.38   in 1957   29.14   in 2001  
Average Barometer   30.20   29.75   29.97   +00.23   30.49   in 1957   29.37   in 2001  
Average Wind   8.2   12.4   8.6   -0.4   20.4   in 2018   1.5   in 1967  
Direction   NNW   WNW   WNW       NW         ESE        
High Wind Gust   23   33   27   -4   52   in 1956   9   in 1967  
Direction   NNW   WNW   WNW       WNW         ESE        
High Heat Index                                      
Wind Chill   12   8   15   -3             -8   in 1979  
Maximum Water Temp   45.3   41.3   45.5   -0.2   51.5   in 2011   39.9   in 2007  
Minimum Water Temp   43.2   39.1   43.2   +0.0   50.2   in 2015   37.5   in 2007  
Average Water Temp   44.3   40.2   44.4   -0.1   50.4   in 2015   38.7   in 2007  
Sunrise/ AM Twilight   7:07:15 AM   6:35:56 AM            
Sunset / PM Twilight   4:17:46 PM   4:49:05 PM            
Length Of Day   9:10:31                          
Special Conditions   None                                  
Comments      
    December 18, 2020     Record Record
Month-to-Date Summary   Observed   2019   Normal Depart Highest Lowest
 Avg Maximum Temperature   43.7   42.9   43.9   -0.2   54.6   in 2015   30.7   in 1904  
Avg Minimum Temperature   32.0   29.8   30.2   +1.8   41.8   in 2015   16.4   in 1989  
Average Temperature   38.1   36.7   37.0   +1.1   48.5   in 2015   25.1   in 1904  
Total Precipitation   4.23   5.28   2.63   +1.60   7.74   in 1936   .27   in 1998  
Total Snow   7.4   8.4   3.7   +3.7   21.3   in 1981   0.0   in 2015  
Total HDD   485   510   499   -14   719   in 1904   297   in 2015  
Total CDD   0   0   0   +0   0   in         in    
Avg Maximum Dew Point   37.2   37.9   35.9   +1.3   49.3   in 2015   18.1   in 1989  
Avg Minimum Dew Point   24.1   22.1   20.7   +3.3   37.4   in 2015   -0.4   in 1989  
Average  Dew Point   30.8   30.3   28.3   +2.5   43.6   in 2015   8.8   in 1989  
    December 18, 2020     Record Record
Year-to-Date Summary   Observed   2019   Normal Depart Highest Lowest
Total Precipitation   41.11   54.78   46.61   -5.50   63.81   in 1983   27.14   in 1965  
Total Snow (since Jul 1 20)   8.0   8.4   4.8   +3.2   21.3   in 1981   0.0   in 2015  
Total HDD (since Jul 1 20)   1278   1500   1531   -253   2031   in 1904   1092   in 2015  
Total CDD (since Jan 1)   871   731   563   +308   871   in 2020   290   in 1902  
                                   
Hour-by-Hour Weather For December 18, 2020  
Climate Weather for December 18  
Weather History For December 18  
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