Carcross
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Carcross clear sky chart from 2005-11-06 to 2024-03-08.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
35%
22659
5%
82075
4%
22547
36%
22547
9%
64973

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 10thNight
32%
911
4%
5502
6%
898
35%
898
4%
4807
January11th to 20thNight
25%
839
11%
4912
3%
820
29%
820
4%
3525
January21st to endNight
25%
927
4%
5533
5%
902
30%
902
3%
4661
February1st to 10thNight
35%
850
8%
2812
5%
850
38%
850
10%
2238
February11th to 20thNight
31%
834
8%
2590
6%
830
33%
830
12%
2047
February21st to endNight
36%
703
11%
2065
7%
703
38%
703
16%
1556
March1st to 10thNight
41%
759
13%
2267
10%
759
42%
759
17%
1676
March11th to 20thNight
34%
660
7%
2100
7%
660
37%
660
11%
1677
March21st to endNight
43%
594
8%
1996
8%
594
45%
594
13%
1517
April1st to 10thNight
46%
540
6%
1796
5%
540
47%
540
15%
1307
April11th to 20thNight
47%
533
7%
1424
4%
533
48%
533
19%
1061
April21st to endNight
48%
540
2%
1440
1%
540
49%
540
18%
1086
May1st to 10thNight
54%
374
0%
1175
0%
374
54%
374
19%
838
May11th to 20thNight
49%
354
0%
1062
0%
354
49%
354
20%
748
May21st to endNight
53%
389
0%
1096
0%
388
54%
388
24%
762
June1st to 10thNight
47%
194
0%
734
0%
194
47%
194
16%
501
June11th to 20thNight
49%
180
0%
720
0%
180
49%
180
12%
509
June21st to endNight
51%
180
0%
720
0%
180
51%
180
15%
495
July1st to 10thNight
56%
175
0%
704
0%
175
56%
175
19%
462
July11th to 20thNight
44%
257
0%
953
0%
257
44%
257
10%
732
July21st to endNight
48%
394
0%
1116
0%
372
48%
372
16%
842
August1st to 10thNight
48%
412
0%
1122
0%
410
48%
410
21%
811
August11th to 20thNight
41%
534
1%
1415
1%
534
41%
534
17%
1083
August21st to endNight
38%
594
2%
1584
2%
594
38%
594
13%
1279
September1st to 10thNight
37%
540
4%
1771
3%
540
38%
540
11%
1389
September11th to 20thNight
42%
540
11%
1800
11%
540
44%
540
16%
1277
September21st to endNight
30%
715
6%
2037
4%
715
31%
715
11%
1635
October1st to 10thNight
30%
720
7%
2160
5%
720
32%
720
11%
1731
October11th to 20thNight
29%
720
5%
2340
4%
720
30%
720
8%
1927
October21st to endNight
27%
884
4%
2757
2%
884
29%
884
10%
2274
November1st to 10thNight
27%
830
3%
2776
3%
830
28%
830
7%
2378
November11th to 20thNight
24%
850
3%
2987
3%
850
24%
850
4%
2634
November21st to endNight
21%
914
3%
3104
2%
914
23%
914
6%
2654
December1st to 10thNight
27%
1040
5%
3230
3%
1040
29%
1040
6%
2796
December11th to 20thNight
30%
1039
6%
4148
3%
1039
33%
1039
7%
3366
December21st to endNight
29%
1140
4%
6127
5%
1114
31%
1114
4%
4692

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
9%12%5%10%9%5%7%6%6%8%23%
76959
Night
6%14%6%12%10%5%7%6%6%8%19%
82552
TransparencyDay
57%11%17%12%3
76616
Night
61%10%14%11%41
82476
SeeingDay
15%13%28%26%14%4
16075
Night
13%8%26%32%18%3
22704

By Month

Percentage Cloud Cover NW (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
310%6%12%17%9%14%10%5%7%8%
1460
11th to 20thDay
5%14%7%15%10%35%7%6%11%16%
1857
21st to endDay
6%24%7%17%8%5%6%5%5%6%11%
2122
February1st to 10thDay
311%6%13%12%7%10%6%6%6%20%
1368
11th to 20thDay
411%8%12%10%6%9%6%7%8%20%
1480
21st to endDay
29%8%14%12%7%8%6%6%9%20%
1386
March1st to 10thDay
29%6%11%11%9%10%6%6%7%22%
1853
11th to 20thDay
314%7%15%12%5%7%7%8%6%16%
1858
21st to endDay
311%6%13%12%5%9%8%6%6%21%
2360
April1st to 10thDay
310%7%13%9%6%7%6%7%8%23%
2164
11th to 20thDay
412%8%11%9%5%7%5%7%8%23%
2482
21st to endDay
5%14%7%10%8%48%6%5%7%25%
2520
May1st to 10thDay
6%12%5%8%8%5%7%7%9%8%25%
2784
11th to 20thDay
8%12%48%7%46%5%6%7%32%
2833
21st to endDay
8%9%47%8%47%6%6%8%33%
3178
June1st to 10thDay
11%10%37%8%46%7%6%8%29%
3224
11th to 20thDay
13%9%49%8%5%6%7%7%9%24%
3240
21st to endDay
8%7%48%8%5%7%7%7%9%30%
3240
July1st to 10thDay
11%7%38%7%5%8%7%7%9%29%
3235
11th to 20thDay
14%7%49%8%5%7%7%9%10%21%
2976
21st to endDay
13%8%37%7%47%5%6%8%30%
3135
August1st to 10thDay
12%7%36%7%46%6%7%9%32%
2808
11th to 20thDay
16%10%48%8%5%6%6%6%8%24%
2485
21st to endDay
20%12%47%7%46%6%6%6%22%
2772
September1st to 10thDay
18%12%5%8%7%5%6%5%5%6%21%
2188
11th to 20thDay
13%11%48%7%46%5%6%7%28%
2160
21st to endDay
16%17%5%11%7%36%6%6%6%17%
1921
October1st to 10thDay
13%15%5%9%7%5%5%6%5%7%22%
1800
11th to 20thDay
10%16%7%10%9%5%6%6%7%6%17%
1620
21st to endDay
8%17%6%11%11%6%7%6%5%7%17%
1598
November1st to 10thDay
8%18%6%14%12%7%7%45%6%11%
1302
11th to 20thDay
5%19%9%20%13%46%5%35%10%
1192
21st to endDay
6%16%7%13%10%6%7%7%7%8%12%
1055
December1st to 10thDay
5%15%7%13%11%6%9%6%9%8%11%
950
11th to 20thDay
311%6%12%10%7%9%7%9%11%15%
967
21st to endDay
5%16%7%15%11%7%8%6%6%7%13%
1386
January1st to 10thNight
412%6%15%14%9%12%8%5%5%10%
5513
11th to 20thNight
411%8%14%10%5%6%6%9%13%14%
5039
21st to endNight
8%21%7%16%9%5%7%5%5%6%11%
5535
February1st to 10thNight
312%7%13%11%6%7%7%7%8%19%
2812
11th to 20thNight
412%6%11%11%5%8%7%8%8%20%
2587
21st to endNight
210%7%12%11%5%7%6%5%9%24%
2065
March1st to 10thNight
212%7%11%8%6%7%7%6%9%25%
2267
11th to 20thNight
214%8%14%10%7%7%8%5%6%20%
2098
21st to endNight
411%7%12%10%5%8%7%6%8%24%
1996
April1st to 10thNight
411%5%12%8%5%7%6%7%9%28%
1796
11th to 20thNight
5%12%48%10%5%6%6%7%9%28%
1424
21st to endNight
5%14%48%7%47%6%6%8%30%
1440
May1st to 10thNight
5%10%47%7%37%8%8%11%31%
1175
11th to 20thNight
6%9%5%10%7%36%6%6%8%34%
1062
21st to endNight
8%7%37%8%45%8%7%10%32%
1096
June1st to 10thNight
13%5%48%8%46%5%6%7%32%
734
11th to 20thNight
12%10%38%9%46%6%7%9%24%
720
21st to endNight
7%5%38%9%5%8%6%10%10%28%
720
July1st to 10thNight
9%5%36%8%45%9%9%10%32%
724
11th to 20thNight
12%7%6%10%8%5%7%7%6%9%23%
983
21st to endNight
11%5%210%8%5%7%6%8%8%30%
1182
August1st to 10thNight
10%7%36%7%45%5%9%9%35%
1128
11th to 20thNight
13%7%38%7%47%6%8%9%29%
1415
21st to endNight
19%12%37%6%5%5%5%6%7%26%
1584
September1st to 10thNight
13%11%5%9%7%47%6%8%7%25%
1771
11th to 20thNight
11%9%46%8%46%6%6%8%32%
1800
21st to endNight
15%14%5%8%8%5%6%6%5%6%20%
2037
October1st to 10thNight
12%15%5%8%8%5%6%6%6%7%22%
2160
11th to 20thNight
12%19%7%9%9%45%5%5%5%19%
2340
21st to endNight
8%16%7%13%10%5%6%6%5%6%17%
2757
November1st to 10thNight
7%16%8%15%12%6%6%5%6%7%12%
2776
11th to 20thNight
417%9%18%13%5%6%5%6%6%8%
2987
21st to endNight
417%7%15%11%7%7%7%6%7%11%
3104
December1st to 10thNight
6%13%7%15%12%6%8%7%7%7%12%
3230
11th to 20thNight
413%8%15%12%6%8%6%6%8%14%
4225
21st to endNight
420%7%13%9%5%8%6%6%7%15%
6270

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
69%13%7%6%31
1460
11th to 20thDay
62%8%11%8%10%2
1875
21st to endDay
73%7%9%9%2
2122
February1st to 10thDay
62%8%9%10%9%2
1368
11th to 20thDay
61%10%12%9%8%1
1488
21st to endDay
60%9%12%13%5%1
1386
March1st to 10thDay
59%9%14%9%7%2
1853
11th to 20thDay
64%9%13%10%4
1858
21st to endDay
61%10%14%8%6%
2360
April1st to 10thDay
57%11%17%11%4
2164
11th to 20thDay
58%8%16%13%4
2482
21st to endDay
56%10%17%13%5%
2520
May1st to 10thDay
53%13%18%14%2
2784
11th to 20thDay
48%9%15%22%6%
2836
21st to endDay
46%10%21%19%4
3179
June1st to 10thDay
50%10%22%14%3
3224
11th to 20thDay
53%11%23%12%2
3240
21st to endDay
47%13%24%14%2
3240
July1st to 10thDay
48%12%22%14%4
3146
11th to 20thDay
54%16%21%8%1
2883
21st to endDay
50%13%22%13%2
2961
August1st to 10thDay
45%14%24%14%2
2789
11th to 20thDay
57%11%19%12%1
2485
21st to endDay
61%12%17%9%1
2772
September1st to 10thDay
62%10%14%12%2
2188
11th to 20thDay
53%11%18%16%3
2160
21st to endDay
67%9%14%8%2
1921
October1st to 10thDay
62%12%14%10%2
1800
11th to 20thDay
65%11%16%6%2
1620
21st to endDay
66%10%14%9%1
1598
November1st to 10thDay
69%11%12%6%1
1302
11th to 20thDay
75%7%9%6%2
1192
21st to endDay
67%10%12%8%3
1055
December1st to 10thDay
66%13%13%7%1
950
11th to 20thDay
56%11%10%18%5%
969
21st to endDay
65%8%13%9%4
1386
January1st to 10thNight
70%14%8%5%3
5513
11th to 20thNight
58%7%9%11%9%5%
5083
21st to endNight
72%8%10%7%2
5535
February1st to 10thNight
60%10%9%10%9%1
2812
11th to 20thNight
58%10%12%11%7%1
2590
21st to endNight
54%9%14%16%6%1
2065
March1st to 10thNight
55%6%15%16%7%2
2267
11th to 20thNight
62%8%10%15%5%
2100
21st to endNight
56%9%17%12%6%
1996
April1st to 10thNight
52%9%17%17%4
1796
11th to 20thNight
50%9%18%17%5%
1424
21st to endNight
52%9%16%18%5%
1440
May1st to 10thNight
43%14%25%15%3
1175
11th to 20thNight
46%10%12%22%9%1
1062
21st to endNight
42%10%21%21%5%
1096
June1st to 10thNight
47%10%23%17%3
734
11th to 20thNight
51%11%28%9%1
720
21st to endNight
44%14%26%15%1
720
July1st to 10thNight
41%12%27%15%5%
704
11th to 20thNight
54%15%21%10%
953
21st to endNight
48%14%25%10%2
1116
August1st to 10thNight
43%14%26%15%2
1122
11th to 20thNight
50%12%25%11%2
1415
21st to endNight
57%12%20%10%1
1584
September1st to 10thNight
56%13%18%12%1
1771
11th to 20thNight
47%11%20%18%3
1800
21st to endNight
62%8%15%12%3
2037
October1st to 10thNight
60%9%15%13%2
2160
11th to 20thNight
65%9%16%7%2
2340
21st to endNight
62%11%16%9%1
2757
November1st to 10thNight
70%9%13%6%2
2776
11th to 20thNight
74%10%9%6%2
2987
21st to endNight
70%9%11%8%1
3104
December1st to 10thNight
68%12%10%8%2
3230
11th to 20thNight
65%8%11%11%4
4222
21st to endNight
63%8%11%10%7%2
6270

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
47%32%28%19%10%
90
11th to 20thDay
17%7%21%27%22%7%
175
21st to endDay
16%15%27%23%16%4
217
February1st to 10thDay
11%8%31%31%14%5%
370
11th to 20thDay
8%13%32%28%12%6%
365
21st to endDay
7%12%37%26%13%5%
307
March1st to 10thDay
7%13%31%31%13%5%
362
11th to 20thDay
10%15%34%26%13%2
340
21st to endDay
8%19%30%22%18%3
456
April1st to 10thDay
9%15%34%26%13%3
420
11th to 20thDay
8%17%24%30%18%3
586
21st to endDay
11%16%31%29%13%2
600
May1st to 10thDay
13%14%30%29%12%2
603
11th to 20thDay
12%12%28%25%16%7%
625
21st to endDay
12%11%28%27%18%4
747
June1st to 10thDay
16%9%26%29%16%4
810
11th to 20thDay
17%10%27%27%16%3
810
21st to endDay
11%11%26%28%21%3
810
July1st to 10thDay
13%8%24%30%20%5%
791
11th to 20thDay
18%11%24%28%15%3
618
21st to endDay
16%11%24%27%18%4
684
August1st to 10thDay
16%12%27%27%14%4
626
11th to 20thDay
27%19%23%21%8%1
615
21st to endDay
26%12%27%24%9%1
693
September1st to 10thDay
29%16%23%18%11%2
460
11th to 20thDay
21%14%26%24%12%3
450
21st to endDay
24%22%29%17%6%1
417
October1st to 10thDay
24%19%31%16%8%2
360
11th to 20thDay
22%17%32%19%8%3
360
21st to endDay
14%14%28%27%14%3
396
November1st to 10thDay
16%18%28%26%8%4
180
11th to 20thDay
16%9%29%27%15%4
180
21st to endDay
8%17%32%28%9%5%
180
December1st to 10thDay
10%12%31%25%18%4
180
11th to 20thDay
14%424%28%19%11%
93
21st to endDay
314%30%25%19%8%
99
January1st to 10thNight
10%5%28%34%20%3
932
11th to 20thNight
13%11%32%29%13%3
850
21st to endNight
12%12%29%29%15%3
935
February1st to 10thNight
9%8%26%41%13%2
850
11th to 20thNight
9%10%33%32%14%3
834
21st to endNight
6%7%34%35%15%3
703
March1st to 10thNight
6%9%29%32%21%4
759
11th to 20thNight
8%8%28%36%18%2
660
21st to endNight
6%9%23%32%23%7%
594
April1st to 10thNight
7%7%22%36%25%4
540
11th to 20thNight
8%6%24%31%27%4
533
21st to endNight
13%6%20%35%23%4
540
May1st to 10thNight
8%6%21%33%28%4
374
11th to 20thNight
12%5%20%35%25%3
354
21st to endNight
11%6%17%33%30%3
389
June1st to 10thNight
16%222%32%28%1
194
11th to 20thNight
17%316%34%29%1
180
21st to endNight
8%322%34%32%1
180
July1st to 10thNight
11%319%40%25%1
175
11th to 20thNight
15%6%18%39%21%
257
21st to endNight
12%5%24%35%23%2
394
August1st to 10thNight
14%6%22%33%24%1
412
11th to 20thNight
18%7%27%29%17%3
534
21st to endNight
25%6%21%29%17%2
594
September1st to 10thNight
20%8%26%30%16%1
540
11th to 20thNight
16%9%24%29%19%4
540
21st to endNight
23%12%25%25%12%3
715
October1st to 10thNight
22%13%25%25%14%2
720
11th to 20thNight
22%11%22%29%13%2
720
21st to endNight
15%7%31%30%14%2
884
November1st to 10thNight
14%9%24%35%15%2
830
11th to 20thNight
13%10%25%31%17%4
850
21st to endNight
12%14%27%29%15%3
914
December1st to 10thNight
12%10%28%32%17%3
1040
11th to 20thNight
15%7%23%35%16%5%
1040
21st to endNight
13%9%27%31%16%4
1144
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