Flags and codes
In weathercan: Download Weather Data from Environment and Climate Change Canada

What are flags/codes

The data output of the weather_dl() function include corresponding _flag columns for each data column. These columns are used by ECCC to add notes regarding measurements.

Similarly, the data output of the normals_dl() function include corresponding _code columns. These columns are used by ECCC to add notes regarding the amount of data used to calculate the normals.

Flags

In the weather_dl() function if format = TRUE (the default), data corresponding to flags M, NA, [empty] and L are all replaced with NA.

For example, a sample of unformatted data from Magog station in Quebec looks like:

## # A tibble: 12 × 6
##    station_name `Date/Time` `Total Precip (mm)` `Total Precip Fl… `Snow Grnd Last … `Snow Grnd Last…
##    <chr>        <chr>       <chr>               <chr>             <chr>             <chr>           
##  1 MAGOG        2017-03     30.4                ^                 <NA>              M               
##  2 MAGOG        2017-04     114.0               ^                 0                 <NA>            
##  3 MAGOG        2017-05     78.8                ^                 0                 <NA>            
##  4 MAGOG        2017-06     140.7               ^                 0                 <NA>            
##  5 MAGOG        2017-07     80.7                <NA>              0                 <NA>            
##  6 MAGOG        2017-08     135.8               <NA>              0                 <NA>            
##  7 MAGOG        2017-09     63.0                ^                 0                 <NA>            
##  8 MAGOG        2017-10     140.8               ^                 0                 <NA>            
##  9 MAGOG        2017-11     70.0                ^                 0                 <NA>            
## 10 MAGOG        2017-12     45.7                ^                 10                <NA>            
## 11 MAGOG        2018-01     34.6                ^                 2                 <NA>            
## 12 MAGOG        2018-02     77.2                ^                 0                 <NA>

In this output, you can see two flags: ^ in Total Precip and M in Snow Grnd Last Day

This same sample, formatted looks like:

## # A tibble: 12 × 5
##    date       total_precip total_precip_flag snow_grnd_last_day snow_grnd_last_day_flag
##    <date>            <dbl> <chr>                          <dbl> <chr>                  
##  1 2017-03-01         30.4 ^                                 NA M                      
##  2 2017-04-01        114   ^                                  0 <NA>                   
##  3 2017-05-01         78.8 ^                                  0 <NA>                   
##  4 2017-06-01        141.  ^                                  0 <NA>                   
##  5 2017-07-01         80.7 <NA>                               0 <NA>                   
##  6 2017-08-01        136.  <NA>                               0 <NA>                   
##  7 2017-09-01         63   ^                                  0 <NA>                   
##  8 2017-10-01        141.  ^                                  0 <NA>                   
##  9 2017-11-01         70   ^                                  0 <NA>                   
## 10 2017-12-01         45.7 ^                                 10 <NA>                   
## 11 2018-01-01         34.6 ^                                  2 <NA>                   
## 12 2018-02-01         77.2 ^                                  0 <NA>

As you can see, we still have the two flags, but the missing data flag (M) is now replaced with NA. The other flag ^ is not, as it indicates that "The value displayed is based on incomplete data" (see below).

Flags - Weather Data

The flags index can be accessed through the built in data frame: flags

|code |meaning | |:-------|:-------------------------------------------------------------------| |[empty] |Indicates an unobserved value | |† |Data that is not subject to review by the National Climate Archives | |^ |The value displayed is based on incomplete data | |A |Accumulated | |B |More than one occurrence and estimated | |C |Precipitation occurred, amount uncertain | |E |Estimated | |F |Accumulated and estimated | |L |Precipitation may or may not have occurred | |M |Missing | |N |Temperature missing but known to be > 0 | |S |More than one occurrence | |T |Trace | |Y |Temperature missing but known to be < 0 | |NA |Not Available |

Codes

In the normals_dl() function, codes are associated with each variable:

## # A tibble: 13 × 7
##    period temp_daily_average temp_daily_average_code temp_daily_max temp_daily_max_c… temp_daily_min
##    <fct>               <dbl> <chr>                            <dbl> <chr>                      <dbl>
##  1 Jan                 -16.6 A                                -11.1 A                          -21.9
##  2 Feb                 -13.6 A                                 -8.1 A                          -19  
##  3 Mar                  -6.2 A                                 -1   A                          -11.4
##  4 Apr                   4   A                                 10.5 A                           -2.6
##  5 May                  10.6 A                                 17.8 A                            3.4
##  6 Jun                  15.9 A                                 22.4 A                            9.3
##  7 Jul                  18.5 A                                 25.2 A                           11.7
##  8 Aug                  17.7 A                                 24.9 A                           10.4
##  9 Sep                  11.8 A                                 18.9 A                            4.7
## 10 Oct                   4.1 A                                 10.4 A                           -2.2
## 11 Nov                  -5.6 A                                 -0.5 A                          -10.6
## 12 Dec                 -14   A                                 -9   A                          -19  
## 13 Year                  2.2 A                                  8.4 A                           -3.9
## # … with 1 more variable: temp_daily_min_code <chr>

For example, here, the code indicates that these temperature variables meet the WMO '3 and 5 rule' (no more than 3 consecutive and no more than 5 total missing for either temperature or precipitation).

Codes - Climate Normals

The codes index for climate normals can be accessed through the built-in data frame: codes

|code |meaning | |:----|:-----------------------------------------------------------------------------------------------------------------------------| |A |WMO '3 and 5 rule' (i.e. no more than 3 consecutive and no more than 5 total missing for either temperature or precipitation) | |B |At least 25 years | |C |At least 20 years | |D |At least 15 years |