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Talmage Observatory at Starfield
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Talmage Observatory at Starfield clear sky chart from 2005-11-05 to 2020-06-03.

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
28%
18282
19%
57771
8%
18250
40%
18250
21%
37588

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 15thNight
19%
900
20%
3136
7%
896
36%
896
16%
1990
January16th to endNight
16%
960
19%
3360
5%
960
34%
960
15%
2163
February1st to 15thNight
15%
884
18%
2799
4%
881
31%
881
15%
1885
February16th to endNight
20%
791
23%
2373
7%
791
39%
791
19%
1562
March1st to 15thNight
17%
900
18%
2672
6%
900
31%
900
17%
1856
March16th to endNight
23%
960
23%
2573
6%
960
36%
960
24%
1696
April1st to 15thNight
21%
898
19%
2246
5%
898
30%
898
21%
1589
April16th to endNight
24%
689
19%
2025
6%
689
34%
689
20%
1373
May1st to 15thNight
26%
675
15%
2025
7%
675
33%
675
19%
1400
May16th to endNight
31%
522
12%
1932
10%
521
37%
521
14%
1331
June1st to 15thNight
33%
425
12%
1701
10%
425
45%
425
15%
1158
June16th to endNight
43%
420
10%
1680
12%
420
49%
420
20%
1051
July1st to 15thNight
54%
400
14%
1600
20%
400
58%
400
23%
943
July16th to endNight
57%
440
15%
1674
18%
418
62%
418
25%
975
August1st to 15thNight
50%
584
17%
1815
13%
582
54%
582
27%
1140
August16th to endNight
51%
781
22%
2119
12%
781
55%
781
33%
1329
September1st to 15thNight
45%
840
20%
2190
10%
840
50%
840
33%
1398
September16th to endNight
45%
837
27%
2310
16%
837
55%
837
36%
1372
October1st to 15thNight
34%
840
21%
2355
9%
840
44%
840
24%
1575
October16th to endNight
24%
896
18%
2912
8%
896
37%
896
19%
1868
November1st to 15thNight
27%
880
22%
2862
9%
880
43%
880
20%
1812
November16th to endNight
25%
900
21%
2925
9%
900
40%
900
19%
1856
December1st to 15thNight
18%
900
19%
3127
6%
900
35%
900
17%
2049
December16th to endNight
17%
960
19%
3360
5%
960
34%
960
15%
2217

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
17%6%25%42445%6%39%
58644
Night
17%6%25%424446%40%
57941
Cloud CoverDay
17%6%2442445%6%40%
58654
Night
17%6%25%424446%40%
57946
TransparencyDay
44%411%22%14%2
58332
Night
44%410%22%15%2
57771
SeeingDay
22%16%32%19%7%2
9271
Night
21%12%31%25%8%
18282

By Month

Percentage Cloud Cover NE (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 15thDay
16%7%2442435%6%42%
1792
16th to endDay
14%8%35%435%446%41%
1920
February1st to 15thDay
18%7%36%43445%6%36%
2046
16th to endDay
13%10%35%6%24445%39%
1980
March1st to 15thDay
19%8%35%5%24346%35%
2267
16th to endDay
15%9%35%323245%43%
2705
April1st to 15thDay
18%8%25%424346%38%
2692
16th to endDay
20%7%26%424336%38%
2868
May1st to 15thDay
24%6%25%5%24446%31%
2917
16th to endDay
18%6%25%4245%5%7%36%
3251
June1st to 15thDay
23%7%25%43445%6%33%
2968
16th to endDay
18%6%25%5%35%5%5%7%34%
2940
July1st to 15thDay
12%424435%5%6%9%39%
2940
16th to endDay
13%5%25%5%35%6%6%7%38%
3102
August1st to 15thDay
13%5%245%345%6%9%38%
2701
16th to endDay
11%414425%5%6%8%44%
2784
September1st to 15thDay
14%5%15%424447%45%
2430
16th to endDay
13%413323246%54%
2310
October1st to 15thDay
20%7%25%42434440%
2265
16th to endDay
18%6%24434345%42%
2016
November1st to 15thDay
20%6%23322346%43%
1986
16th to endDay
22%6%14323345%43%
2025
December1st to 15thDay
19%6%3442345%5%39%
1819
16th to endDay
22%9%245%23345%37%
1920
January1st to 15thNight
15%7%25%33446%6%40%
3136
16th to endNight
14%9%36%5%3445%5%38%
3360
February1st to 15thNight
15%8%35%5%35%446%36%
2798
16th to endNight
15%9%25%5%34335%41%
2373
March1st to 15thNight
18%9%25%5%24445%36%
2659
16th to endNight
17%6%24423345%45%
2573
April1st to 15thNight
19%7%34424446%37%
2246
16th to endNight
21%7%25%423345%39%
2025
May1st to 15thNight
20%6%35%5%3446%7%33%
2025
16th to endNight
19%6%26%5%36%45%7%32%
1930
June1st to 15thNight
24%7%15%425%35%6%33%
1701
16th to endNight
18%6%245%235%5%7%38%
1680
July1st to 15thNight
12%4245%36%45%9%41%
1680
16th to endNight
12%414425%5%8%9%41%
1770
August1st to 15thNight
12%5%144345%6%9%41%
1825
16th to endNight
13%32433445%7%46%
2119
September1st to 15thNight
13%414423446%48%
2190
16th to endNight
14%313323346%53%
2310
October1st to 15thNight
19%5%24424345%41%
2355
16th to endNight
20%6%24423445%40%
2912
November1st to 15thNight
19%5%24424445%43%
2862
16th to endNight
18%6%24423346%42%
2925
December1st to 15thNight
20%7%25%424345%38%
3127
16th to endNight
19%7%25%5%23445%38%
3360

Percentage Cloud Cover SE (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 15thDay
16%7%24423345%43%
1792
16th to endDay
15%7%25%425%45%6%41%
1920
February1st to 15thDay
18%6%26%42445%7%36%
2046
16th to endDay
13%9%35%5%2445%5%39%
1980
March1st to 15thDay
20%8%25%5%2445%6%35%
2277
16th to endDay
16%8%25%323346%42%
2705
April1st to 15thDay
18%7%25%434446%38%
2692
16th to endDay
20%7%25%423445%38%
2868
May1st to 15thDay
23%6%25%5%34446%32%
2917
16th to endDay
18%5%25%43445%7%37%
3251
June1st to 15thDay
25%5%245%2445%7%33%
2968
16th to endDay
17%6%25%5%345%5%7%35%
2940
July1st to 15thDay
12%424435%6%7%8%40%
2940
16th to endDay
12%425%5%35%6%6%8%39%
3102
August1st to 15thDay
12%4245%35%5%6%9%39%
2701
16th to endDay
10%4144345%6%9%45%
2784
September1st to 15thDay
13%5%24433446%46%
2430
16th to endDay
13%5%12313346%53%
2310
October1st to 15thDay
21%6%25%43334440%
2265
16th to endDay
18%6%24434345%42%
2016
November1st to 15thDay
20%5%23323346%44%
1986
16th to endDay
21%6%24322345%43%
2025
December1st to 15thDay
20%5%25%424345%40%
1819
16th to endDay
23%8%34324246%36%
1920
January1st to 15thNight
15%7%3442445%6%40%
3136
16th to endNight
15%9%35%5%24445%38%
3360
February1st to 15thNight
15%9%35%5%25%445%37%
2791
16th to endNight
15%8%25%5%24446%40%
2373
March1st to 15thNight
19%8%25%425%445%36%
2672
16th to endNight
17%7%24423345%44%
2572
April1st to 15thNight
19%7%34424446%37%
2246
16th to endNight
21%6%25%423345%39%
2025
May1st to 15thNight
20%6%25%5%345%5%7%33%
2025
16th to endNight
20%6%26%5%35%5%5%7%31%
1930
June1st to 15thNight
24%6%24424446%33%
1701
16th to endNight
18%6%2442346%7%38%
1680
July1st to 15thNight
12%425%5%35%46%7%40%
1680
16th to endNight
12%4145%25%5%7%8%40%
1770
August1st to 15thNight
13%5%245%345%6%8%42%
1825
16th to endNight
14%41442445%8%46%
2119
September1st to 15thNight
14%424433447%47%
2190
16th to endNight
13%413322346%53%
2310
October1st to 15thNight
18%5%25%5%23346%40%
2355
16th to endNight
21%5%15%323445%41%
2912
November1st to 15thNight
19%5%24423435%43%
2862
16th to endNight
19%5%24413346%43%
2925
December1st to 15thNight
21%7%25%423446%38%
3127
16th to endNight
20%7%25%433445%38%
3360

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 15thDay
42%5%9%24%16%2
1793
16th to endDay
43%312%23%14%2
1920
February1st to 15thDay
46%413%22%11%1
2049
16th to endDay
46%310%20%15%3
1980
March1st to 15thDay
50%311%17%13%3
2277
16th to endDay
44%27%20%18%6%
2705
April1st to 15thDay
46%39%20%15%3
2692
16th to endDay
48%39%19%16%2
2868
May1st to 15thDay
52%48%17%16%2
2917
16th to endDay
45%6%13%20%11%2
3255
June1st to 15thDay
49%5%11%20%11%1
2968
16th to endDay
46%5%12%21%13%
2940
July1st to 15thDay
36%7%14%24%16%
2791
16th to endDay
40%5%16%22%13%1
2935
August1st to 15thDay
40%6%17%24%9%
2687
16th to endDay
34%415%27%16%1
2784
September1st to 15thDay
37%5%11%25%17%1
2430
16th to endDay
32%39%29%22%2
2310
October1st to 15thDay
46%38%24%13%2
2265
16th to endDay
43%310%25%14%1
2016
November1st to 15thDay
41%312%25%14%2
1986
16th to endDay
44%313%19%17%2
2025
December1st to 15thDay
45%313%21%15%
1819
16th to endDay
50%310%19%14%1
1920
January1st to 15thNight
43%5%11%23%13%2
3136
16th to endNight
46%310%20%15%2
3360
February1st to 15thNight
48%411%19%14%2
2799
16th to endNight
45%39%22%15%4
2373
March1st to 15thNight
49%48%20%13%2
2672
16th to endNight
42%29%17%21%5%
2573
April1st to 15thNight
46%47%20%18%2
2246
16th to endNight
47%39%19%15%4
2025
May1st to 15thNight
48%5%9%19%14%3
2025
16th to endNight
51%6%12%17%10%1
1932
June1st to 15thNight
51%5%10%20%11%1
1701
16th to endNight
44%5%13%22%13%1
1680
July1st to 15thNight
38%6%14%25%14%
1600
16th to endNight
36%6%16%28%11%
1674
August1st to 15thNight
38%6%14%24%14%
1815
16th to endNight
35%5%11%27%19%
2119
September1st to 15thNight
35%5%11%28%17%1
2190
16th to endNight
31%47%32%20%2
2310
October1st to 15thNight
44%410%23%14%2
2355
16th to endNight
44%310%27%12%1
2912
November1st to 15thNight
42%410%23%16%2
2862
16th to endNight
43%312%23%14%2
2925
December1st to 15thNight
47%311%22%13%
3127
16th to endNight
48%310%21%13%1
3360

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 15thDay
21%30%32%12%2
150
16th to endDay
22%23%36%13%3
160
February1st to 15thDay
29%20%33%14%2
370
16th to endDay
22%25%31%17%3
399
March1st to 15thDay
26%22%35%11%4
450
16th to endDay
22%23%32%13%5%2
480
April1st to 15thDay
31%22%27%11%6%
450
16th to endDay
28%20%29%12%6%1
439
May1st to 15thDay
31%19%29%12%41
468
16th to endDay
20%20%32%19%5%1
523
June1st to 15thDay
22%16%36%18%5%
443
16th to endDay
21%12%40%16%6%1
435
July1st to 15thDay
12%7%36%29%10%3
425
16th to endDay
15%5%34%29%11%3
454
August1st to 15thDay
16%8%30%24%15%3
418
16th to endDay
14%5%31%29%12%6%
460
September1st to 15thDay
17%9%29%26%11%5%
435
16th to endDay
15%9%35%21%9%9%
434
October1st to 15thDay
26%11%24%23%11%2
420
16th to endDay
25%18%32%17%6%
384
November1st to 15thDay
27%16%28%21%5%1
370
16th to endDay
29%18%25%19%6%1
375
December1st to 15thDay
18%24%35%15%4
169
16th to endDay
31%24%31%11%
160
January1st to 15thNight
20%19%36%19%2
900
16th to endNight
23%18%35%19%3
960
February1st to 15thNight
20%19%40%17%1
884
16th to endNight
22%17%34%21%4
791
March1st to 15thNight
25%16%37%18%2
900
16th to endNight
22%15%33%21%6%
960
April1st to 15thNight
25%15%32%22%3
898
16th to endNight
24%14%31%22%7%
689
May1st to 15thNight
23%10%33%25%6%1
675
16th to endNight
24%7%29%28%8%1
522
June1st to 15thNight
27%7%26%29%9%
425
16th to endNight
22%125%35%14%
420
July1st to 15thNight
15%120%43%18%1
400
16th to endNight
13%218%44%18%2
440
August1st to 15thNight
14%323%40%16%
584
16th to endNight
15%322%35%19%2
781
September1st to 15thNight
15%426%34%18%1
840
16th to endNight
16%5%27%27%18%4
837
October1st to 15thNight
22%8%27%25%14%1
840
16th to endNight
25%14%31%22%6%
896
November1st to 15thNight
22%13%31%22%7%1
880
16th to endNight
21%18%29%23%6%
900
December1st to 15thNight
25%14%35%19%4
900
16th to endNight
25%17%35%19%2
960
Page generated at 2020-06-04 03:18:55. Version ac04

Copyright 2020 A. Danko


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