leandro 
		 
		(usa Arch Linux)
		 
		Enviado em 02/11/2014 - 16:28h 
		Tem sim. Teste esta config:
     
# ConkyBrWeather 
# Criado por LeandroNKZ 
# Necessário o uso do BrWeather: 
# http://brweatherproject.blogspot.com/  
# Instruções e instalação: 
# http://va.mu/V59f  
 
# -- Conky settings -- # 
background no 
update_interval 1 
 
cpu_avg_samples 2 
net_avg_samples 2 
 
override_utf8_locale yes 
 
double_buffer yes 
no_buffers yes 
 
text_buffer_size 2048 
imlib_cache_size 0 
 
# -- Window specifications -- # 
 
own_window yes 
own_window_class Conky 
own_window_type desktop 
own_window_argb_visual yes 
own_window_argb_value 180 
 
# -- GNOME -- # 
#own_window yes 
#own_window_type override 
#own_window_transparent yes 
#own_window_hints undecorated,below,above,sticky,skip_taskbar,skip_pager 
 
# -- Openbox -- # 
#own_window yes 
#own_window_transparent yes 
#own_window_type desktop 
 
# -- Alignment -- # 
 
#alignment top_left 
alignment top_right 
#alignment bottom_left 
#alignment bottom_right 
border_inner_margin 0 
border_outer_margin 0 
 
minimum_size 250 200 
maximum_width 250 
 
gap_x 0 
gap_y 0 
 
# -- Graphics settings -- # 
draw_shades no 
draw_outline nos 
draw_borders no 
draw_graph_borders no 
 
# -- Text settings -- # 
use_xft yes 
xftfont Droid Sans:size=10 
xftalpha 0.4 
uppercase no 
 
# -- Colors -- # 
default_color E7F4F8 
color1 FFFFFF 
color2 C8C8C8 
color3 000000 
 
TEXT 
##Cidade 
 
 ${font Droid Sans:size=15}${execi 3600 brweather --option=city | cut -f1 -d'-'} 
 ${hr} 
 ##Condições atuais 
 ${goto 100}${font Droid Sans:size=10}${execi 3600 brweather --option=CNT} 
 ${goto 140}${font Droid Sans:size=25}${execi 3600 brweather --option=TN}°C 
 ${font Droid Sans:size=10}Umidade: ${execi 3600 brweather --option=umid}% 
 ${font Droid Sans:size=10}UV: ${execi 3600 brweather --option=UVN}-${execi 3600 brweather --option=UVNT} 
 ${font Droid Sans:size=10}Poss. de Chuva: ${execi 3600 brweather --option=PC1}% 
 ${hr} 
 ##Previsão para as próximas horas 
 ${font Droid Sans:size=15}${execi 3600 brweather --option=Day1T} 
 ${goto 100}${font Droid Sans:size=10}${execi 3600 brweather --option=C1T} 
 ${goto 140}${font Droid Sans:size=15}${execi 3600 brweather --option=LT1}°C/${execi 3600 brweather --option=HT1}°C 
 ${font Droid Sans:size=10}Umidade: ${execi 3600 brweather --option=umid1} 
 ${font Droid Sans:size=10}UV: ${execi 3600 brweather --option=UV1}-${execi 3600 brweather --option=UV1T} 
 ${font Droid Sans:size=10}Poss. de Chuva: ${execi 3600 brweather --option=PC1}% 
 ${hr} 
 ##Previsão para o segundo dia 
 ${font Droid Sans:size=15}${execi 3600 brweather --option=Day2T} 
 ${goto 100}${font Droid Sans:size=10}${execi 3600 brweather --option=C2T} 
 ${goto 140}${font Droid Sans:size=15}${execi 3600 brweather --option=LT2}°C/${execi 3600 brweather --option=HT2}°C 
 ${font Droid Sans:size=10}Umidade: ${execi 3600 brweather --option=umid2}% 
 ${font Droid Sans:size=10}UV: ${execi 3600 brweather --option=UV2}-${execi 3600 brweather --option=UV2T} 
 ${font Droid Sans:size=10}Poss. de Chuva: ${execi 3600 brweather --option=PC2}% 
 ${hr} 
 ##Previsão para o terceiro dia 
 ${font Droid Sans:size=15}${execi 3600 brweather --option=Day3T} 
 ${goto 100}${font Droid Sans:size=10}${execi 3600 brweather --option=C3T} 
 ${goto 140}${font Droid Sans:size=15}${execi 3600 brweather --option=LT3}°C/${execi 3600 brweather --option=HT3}°C 
 ${font Droid Sans:size=10}Umidade: ${execi 3600 brweather --option=umid3}% 
 ${font Droid Sans:size=10}UV: ${execi 3600 brweather --option=UV3}-${execi 3600 brweather --option=UV3T} 
 ${font Droid Sans:size=10}Poss. de Chuva: ${execi 3600 brweather --option=PC3}% 
 ${hr} \ 
 ##Imagens 
 ${execpi 3600 brweather --imagem6=CN -p 0,50 -s 100x100} \ 
 ${execpi 3600 brweather --imagem6=C1 -p 0,210 -s 80x80} \ 
 ${execpi 3600 brweather --imagem6=C2 -p 0,350 -s 80x80} \ 
 ${execpi 3600 brweather --imagem6=C3 -p 0,485 -s 80x80} \ 
 ##Termometro 
 ${if_match ${execi 3600 brweather --option=TN | sed s/°//}>-110}${if_match ${execi 3600 brweather --option=TN | sed s/°//}<=0}${image ~/.brweather/conky10/termometro/00.png -p 195,80 -s 50x98}${endif}${endif} \ 
 ${if_match ${execi 3600 brweather --option=TN | sed s/°//}>0}${if_match ${execi 3600 brweather --option=TN | sed s/°//}<=5}${image ~/.brweather/conky10/termometro/00.png -p 195,80 -s 50x98}${endif}${endif} \ 
 ${if_match ${execi 3600 brweather --option=TN | sed s/°//}>5}${if_match ${execi 3600 brweather --option=TN | sed s/°//}<=10}${image ~/.brweather/conky10/termometro/05.png -p 195,80 -s 50x98}${endif}${endif} \ 
 ${if_match ${execi 3600 brweather --option=TN | sed s/°//}>10}${if_match ${execi 3600 brweather --option=TN | sed s/°//}<=15}${image ~/.brweather/conky10/termometro/10.png -p 195,80 -s 50x98}${endif}${endif} \ 
 ${if_match ${execi 3600 brweather --option=TN | sed s/°//}>15}${if_match ${execi 3600 brweather --option=TN | sed s/°//}<=20}${image ~/.brweather/conky10/termometro/15.png -p 195,80 -s 50x98}${endif}${endif} \ 
 ${if_match ${execi 3600 brweather --option=TN | sed s/°//}>20}${if_match ${execi 3600 brweather --option=TN | sed s/°//}<=25}${image ~/.brweather/conky10/termometro/20.png -p 195,80 -s 50x98}${endif}${endif} \ 
 ${if_match ${execi 3600 brweather --option=TN | sed s/°//}>25}${if_match ${execi 3600 brweather --option=TN | sed s/°//}<=30}${image ~/.brweather/conky10/termometro/25.png -p 195,80 -s 50x98}${endif}${endif} \ 
 ${if_match ${execi 3600 brweather --option=TN | sed s/°//}>30}${if_match ${execi 3600 brweather --option=TN | sed s/°//}<=35}${image ~/.brweather/conky10/termometro/30.png -p 195,80 -s 50x98}${endif}${endif} \ 
 ${if_match ${execi 3600 brweather --option=TN | sed s/°//}>35}${if_match ${execi 3600 brweather --option=TN | sed s/°//}<=40}${image ~/.brweather/conky10/termometro/35.png -p 195,80 -s 50x98}${endif}${endif} \ 
 ${if_match ${execi 3600 brweather --option=TN | sed s/°//}>40}${if_match ${execi 3600 brweather --option=TN | sed s/°//}<=45}${image ~/.brweather/conky10/termometro/40.png -p 195,80 -s 50x98}${endif}${endif} \ 
 ${if_match ${execi 3600 brweather --option=TN | sed s/°//}>45}${if_match ${execi 3600 brweather --option=TN | sed s/°//}<110}${image ~/.brweather/conky10/termometro/45.png -p 195,80 -s 50x98}${endif}${endif} 
  
Na seção "# -- Window specifications -- #", você pode configurar o valor da transparência. Na opção:
own_window_argb_value 180  
Eu coloquei 180 (vai de 0 até 255), quanto maior o valor, mais escuro fica.
Essa é uma solução "meia-boca" pro seu problema. Já que o Conky não está aceitando transparência "real" (o que ficaria bem melhor), através do parâmetro:
own_window_transparent yes  
Um abraço.