Talkeetna
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Talkeetna clear sky chart from 2005-11-06 to 2024-02-25.

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
32%
21542
8%
81983
5%
21422
36%
21422
11%
60163

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
38%
930
12%
5600
8%
906
45%
906
10%
3726
January11th to 20thNight
27%
935
11%
5270
6%
910
34%
910
8%
3460
January21st to endNight
26%
943
8%
5439
6%
914
33%
914
10%
3077
February1st to 10thNight
31%
850
16%
2908
10%
850
37%
850
17%
1956
February11th to 20thNight
25%
832
7%
2631
5%
830
27%
830
10%
2114
February21st to endNight
29%
587
13%
2039
8%
587
35%
587
12%
1510
March1st to 10thNight
33%
620
16%
2211
9%
620
43%
620
17%
1474
March11th to 20thNight
40%
620
21%
2091
15%
620
50%
620
24%
1289
March21st to endNight
41%
603
13%
2002
10%
603
45%
603
17%
1408
April1st to 10thNight
33%
540
6%
1726
4%
540
35%
540
11%
1361
April11th to 20thNight
47%
533
4%
1423
3%
533
48%
533
19%
1078
April21st to endNight
50%
524
0%
1375
0%
524
50%
524
19%
1039
May1st to 10thNight
42%
360
0%
1080
0%
360
42%
360
11%
876
May11th to 20thNight
44%
329
0%
1038
0%
329
44%
329
15%
779
May21st to endNight
40%
194
0%
794
0%
194
40%
194
14%
543
June1st to 10thNight
36%
180
0%
720
0%
180
36%
180
6%
583
June11th to 20thNight
42%
180
0%
720
0%
180
42%
180
7%
577
June21st to endNight
40%
180
0%
720
0%
180
40%
180
5%
608
July1st to 10thNight
40%
175
0%
700
0%
175
40%
175
7%
577
July11th to 20thNight
33%
184
0%
706
0%
184
33%
184
6%
588
July21st to endNight
35%
394
0%
1032
0%
372
35%
372
9%
877
August1st to 10thNight
29%
358
0%
1068
0%
356
29%
356
6%
947
August11th to 20thNight
30%
446
0%
1317
0%
446
30%
446
7%
1125
August21st to endNight
32%
594
1%
1584
0%
594
33%
594
8%
1377
September1st to 10thNight
30%
540
3%
1704
2%
540
30%
540
7%
1468
September11th to 20thNight
30%
540
5%
1800
5%
540
31%
540
6%
1546
September21st to endNight
32%
580
5%
2044
4%
580
35%
580
9%
1642
October1st to 10thNight
28%
646
6%
2176
6%
646
30%
646
9%
1792
October11th to 20thNight
34%
810
7%
2384
4%
810
35%
810
13%
1888
October21st to endNight
33%
891
10%
2826
6%
891
36%
891
12%
2187
November1st to 10thNight
29%
830
8%
2831
5%
830
32%
830
13%
2109
November11th to 20thNight
34%
850
18%
3069
11%
850
43%
850
18%
2017
November21st to endNight
30%
865
12%
3263
8%
865
37%
865
10%
2453
December1st to 10thNight
26%
940
11%
3420
9%
940
30%
940
10%
2681
December11th to 20thNight
27%
940
6%
4234
4%
939
32%
939
7%
3417
December21st to endNight
27%
1019
6%
6038
4%
1004
32%
1004
6%
4014

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
19%12%48%7%45%5%5%6%26%
76499
Night
16%15%5%8%6%34445%28%
82791
TransparencyDay
59%10%13%12%6%1
76142
Night
57%7%10%13%10%3
82732
SeeingDay
24%7%18%24%20%7%
16924
Night
24%8%23%26%16%3
21579

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
10%14%47%5%5%5%47%6%33%
1269
11th to 20thDay
10%15%48%6%44445%36%
1451
21st to endDay
11%12%47%7%445%5%5%37%
2038
February1st to 10thDay
12%17%5%7%5%33345%38%
1269
11th to 20thDay
15%25%5%8%5%35%5%46%20%
1440
21st to endDay
9%14%48%7%45%5%5%5%33%
1309
March1st to 10thDay
10%16%6%8%5%3333439%
1748
11th to 20thDay
6%10%38%6%35%45%7%45%
1865
21st to endDay
8%12%6%8%7%44445%37%
2354
April1st to 10thDay
11%16%6%9%6%346%6%6%26%
2231
11th to 20thDay
8%13%48%7%35%5%5%6%36%
2486
21st to endDay
11%11%49%7%36%5%5%7%32%
2582
May1st to 10thDay
12%12%6%10%8%46%6%7%7%23%
2880
11th to 20thDay
14%11%49%7%45%5%5%5%31%
2858
21st to endDay
17%10%47%6%45%5%6%8%30%
3478
June1st to 10thDay
19%10%5%8%7%36%5%6%8%23%
3240
11th to 20thDay
20%10%5%8%7%45%5%6%7%22%
3240
21st to endDay
22%9%48%7%46%7%6%8%20%
3240
July1st to 10thDay
23%10%47%7%46%6%6%6%20%
3240
11th to 20thDay
26%9%48%8%46%5%5%7%19%
3228
21st to endDay
28%9%47%7%45%5%5%6%20%
3226
August1st to 10thDay
34%9%47%7%345%5%6%15%
2865
11th to 20thDay
31%10%47%7%45%5%6%6%16%
2582
21st to endDay
33%9%36%6%35%5%5%5%21%
2772
September1st to 10thDay
34%10%48%7%34335%19%
2255
11th to 20thDay
34%13%48%5%3434417%
2160
21st to endDay
24%12%48%6%34445%25%
1913
October1st to 10thDay
29%13%46%5%3445%6%21%
1783
11th to 20thDay
24%11%36%6%5%5%5%46%24%
1576
21st to endDay
19%13%38%6%45%5%45%27%
1530
November1st to 10thDay
13%17%6%6%6%44445%30%
1244
11th to 20thDay
13%12%346%34445%40%
1111
21st to endDay
14%16%7%11%6%36%45%425%
912
December1st to 10thDay
21%18%5%9%8%3336%5%21%
760
11th to 20thDay
8%22%9%13%8%44435%21%
967
21st to endDay
9%16%8%8%7%45%45%430%
1397
January1st to 10thNight
8%17%5%8%7%35%5%5%7%30%
5686
11th to 20thNight
11%15%5%10%6%3433435%
5458
21st to endNight
10%12%36%5%35%445%43%
5630
February1st to 10thNight
9%18%5%7%5%3333439%
2908
11th to 20thNight
15%24%6%9%7%34345%21%
2627
21st to endNight
9%17%5%12%8%35%446%28%
2039
March1st to 10thNight
10%15%5%7%43345%438%
2211
11th to 20thNight
7%10%47%5%3445%7%44%
2091
21st to endNight
9%15%7%9%5%35%33338%
2002
April1st to 10thNight
12%18%6%10%6%44447%24%
1726
11th to 20thNight
8%12%5%7%7%46%6%6%6%32%
1423
21st to endNight
12%12%38%7%46%5%6%433%
1375
May1st to 10thNight
15%15%5%10%8%5%5%6%5%5%21%
1080
11th to 20thNight
11%12%47%8%36%6%6%7%29%
1037
21st to endNight
19%9%36%6%35%47%7%30%
794
June1st to 10thNight
19%13%6%8%9%5%5%5%47%20%
720
11th to 20thNight
21%10%47%9%35%7%5%8%22%
720
21st to endNight
28%7%37%8%5%6%6%7%7%17%
720
July1st to 10thNight
26%10%5%6%8%36%47%8%18%
720
11th to 20thNight
28%10%48%6%45%46%6%18%
730
21st to endNight
27%10%49%7%46%35%5%19%
1092
August1st to 10thNight
34%10%47%8%46%6%5%5%11%
1074
11th to 20thNight
36%10%37%6%35%445%17%
1317
21st to endNight
32%11%38%6%35%5%45%17%
1584
September1st to 10thNight
35%11%48%6%4443318%
1704
11th to 20thNight
35%13%5%7%5%3443416%
1800
21st to endNight
27%12%37%6%35%45%6%22%
2044
October1st to 10thNight
32%16%46%42434420%
2176
11th to 20thNight
23%13%48%7%34445%25%
2384
21st to endNight
21%13%47%6%45%45%6%25%
2826
November1st to 10thNight
14%17%6%7%6%3445%5%28%
2831
11th to 20thNight
14%12%46%6%3345%6%38%
3069
21st to endNight
14%17%6%9%7%45%44427%
3263
December1st to 10thNight
21%20%6%7%5%3345%5%22%
3420
11th to 20thNight
11%25%9%11%6%3444420%
4240
21st to endNight
9%18%6%10%7%45%445%26%
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
44%11%15%16%11%4
1269
11th to 20thDay
46%7%11%20%13%3
1466
21st to endDay
46%6%9%10%20%9%
2038
February1st to 10thDay
49%5%10%14%15%7%
1269
11th to 20thDay
65%5%10%10%8%2
1447
21st to endDay
52%9%8%18%11%2
1309
March1st to 10thDay
51%411%12%17%6%
1748
11th to 20thDay
38%8%8%20%20%4
1865
21st to endDay
48%9%15%12%13%3
2354
April1st to 10thDay
57%9%14%14%6%1
2231
11th to 20thDay
48%10%13%21%8%
2486
21st to endDay
52%7%12%19%9%
2582
May1st to 10thDay
59%11%14%13%3
2880
11th to 20thDay
55%9%13%17%5%
2861
21st to endDay
53%10%14%20%3
3479
June1st to 10thDay
59%11%17%11%2
3240
11th to 20thDay
63%12%13%8%4
3240
21st to endDay
64%17%15%5%
3240
July1st to 10thDay
65%11%15%8%1
3151
11th to 20thDay
67%13%16%3
3129
21st to endDay
66%13%15%6%
3047
August1st to 10thDay
70%12%13%41
2846
11th to 20thDay
69%13%10%7%2
2582
21st to endDay
67%10%14%7%3
2772
September1st to 10thDay
71%10%9%7%3
2255
11th to 20thDay
73%8%10%7%1
2160
21st to endDay
61%11%12%13%3
1913
October1st to 10thDay
64%9%12%12%2
1783
11th to 20thDay
60%8%11%16%42
1576
21st to endDay
58%9%11%13%8%2
1530
November1st to 10thDay
55%7%12%15%8%3
1244
11th to 20thDay
46%6%9%24%14%1
1111
21st to endDay
61%8%8%8%13%2
912
December1st to 10thDay
64%8%7%10%9%1
760
11th to 20thDay
66%6%8%12%6%1
970
21st to endDay
52%5%15%7%15%6%
1397
January1st to 10thNight
50%8%12%15%11%3
5686
11th to 20thNight
51%6%8%16%15%3
5506
21st to endNight
43%5%8%10%20%13%
5630
February1st to 10thNight
50%48%15%16%7%
2908
11th to 20thNight
65%6%8%10%8%3
2631
21st to endNight
58%6%8%14%11%2
2039
March1st to 10thNight
48%6%9%14%17%6%
2211
11th to 20thNight
40%6%8%20%23%3
2093
21st to endNight
51%7%11%14%13%4
2002
April1st to 10thNight
62%7%11%14%5%1
1726
11th to 20thNight
52%9%10%20%9%1
1423
21st to endNight
53%7%14%18%8%
1375
May1st to 10thNight
65%6%12%14%2
1080
11th to 20thNight
53%10%13%18%6%
1038
21st to endNight
51%7%15%22%4
794
June1st to 10thNight
64%11%14%9%1
720
11th to 20thNight
61%13%13%9%4
720
21st to endNight
66%13%15%6%
720
July1st to 10thNight
65%11%16%8%
700
11th to 20thNight
66%12%18%4
706
21st to endNight
68%9%18%5%
1032
August1st to 10thNight
70%13%13%41
1068
11th to 20thNight
68%10%14%7%1
1317
21st to endNight
69%9%12%7%2
1584
September1st to 10thNight
72%8%9%9%2
1704
11th to 20thNight
72%8%9%10%1
1800
21st to endNight
65%8%11%13%3
2044
October1st to 10thNight
67%8%11%11%4
2176
11th to 20thNight
61%7%13%11%6%1
2384
21st to endNight
59%8%10%13%9%1
2826
November1st to 10thNight
57%7%12%15%7%2
2831
11th to 20thNight
47%6%12%24%11%
3069
21st to endNight
60%7%8%10%12%3
3263
December1st to 10thNight
64%6%7%11%10%1
3420
11th to 20thNight
67%7%7%11%7%1
4236
21st to endNight
53%6%13%11%12%5%
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
13%10%26%33%16%2
90
11th to 20thDay
19%15%25%24%13%4
208
21st to endDay
24%13%24%24%12%3
308
February1st to 10thDay
15%12%27%23%15%9%
280
11th to 20thDay
24%13%23%23%15%3
347
21st to endDay
18%9%25%27%15%6%
293
March1st to 10thDay
18%11%27%22%17%5%
340
11th to 20thDay
14%7%21%31%18%8%
405
21st to endDay
13%8%21%26%22%11%
572
April1st to 10thDay
15%9%23%27%17%9%
533
11th to 20thDay
14%6%17%28%25%11%
590
21st to endDay
16%416%31%27%6%
600
May1st to 10thDay
16%7%20%27%25%5%
603
11th to 20thDay
18%7%21%29%20%6%
625
21st to endDay
23%6%22%28%18%3
853
June1st to 10thDay
23%6%15%25%25%6%
810
11th to 20thDay
22%6%17%25%23%7%
810
21st to endDay
22%5%12%19%29%12%
810
July1st to 10thDay
23%5%13%25%24%9%
796
11th to 20thDay
27%5%16%25%20%7%
792
21st to endDay
29%314%20%23%11%
773
August1st to 10thDay
33%7%15%21%16%8%
626
11th to 20thDay
31%8%17%21%17%6%
615
21st to endDay
35%5%14%18%19%9%
693
September1st to 10thDay
35%417%18%18%8%
562
11th to 20thDay
39%6%11%17%17%10%
540
21st to endDay
30%7%14%21%18%9%
376
October1st to 10thDay
35%6%16%22%16%6%
360
11th to 20thDay
27%8%18%22%19%6%
360
21st to endDay
28%7%21%26%15%4
396
November1st to 10thDay
24%7%24%24%17%4
338
11th to 20thDay
18%10%22%28%16%6%
251
21st to endDay
20%14%20%28%13%4
90
December1st to 10thDay
23%11%21%37%8%
90
11th to 20thDay
19%11%30%29%9%2
90
21st to endDay
29%12%22%21%12%3
99
January1st to 10thNight
14%11%25%30%17%3
940
11th to 20thNight
20%13%26%28%11%2
940
21st to endNight
25%10%30%26%9%1
947
February1st to 10thNight
17%12%27%25%16%2
850
11th to 20thNight
24%12%28%25%9%1
834
21st to endNight
17%9%27%32%13%2
587
March1st to 10thNight
17%10%30%26%15%2
620
11th to 20thNight
12%6%30%33%17%3
620
21st to endNight
17%5%22%25%25%6%
603
April1st to 10thNight
19%8%23%25%20%5%
540
11th to 20thNight
13%6%21%30%24%7%
533
21st to endNight
17%413%29%32%5%
524
May1st to 10thNight
16%6%16%26%31%5%
360
11th to 20thNight
16%5%23%31%24%2
329
21st to endNight
23%6%21%29%20%2
195
June1st to 10thNight
24%6%19%27%23%1
180
11th to 20thNight
23%312%36%24%1
180
21st to endNight
27%7%11%26%27%2
180
July1st to 10thNight
23%418%33%20%2
175
11th to 20thNight
33%5%17%25%20%1
184
21st to endNight
31%416%22%23%4
394
August1st to 10thNight
37%418%21%17%3
358
11th to 20thNight
38%6%12%24%17%2
446
21st to endNight
37%412%23%19%5%
594
September1st to 10thNight
38%5%14%20%19%4
540
11th to 20thNight
40%6%11%19%19%5%
540
21st to endNight
32%5%17%26%14%5%
580
October1st to 10thNight
41%6%17%19%14%4
646
11th to 20thNight
28%6%21%24%18%3
810
21st to endNight
26%7%22%27%16%2
891
November1st to 10thNight
25%8%26%25%14%1
830
11th to 20thNight
22%6%28%30%13%1
850
21st to endNight
25%11%22%25%14%3
865
December1st to 10thNight
30%8%25%24%11%2
940
11th to 20thNight
21%10%28%26%12%4
940
21st to endNight
25%10%24%25%14%2
1034
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