Taxahaw
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Taxahaw clear sky chart from 2005-11-05 to 2017-03-19.

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
47%
15236
22%
45172
15%
15198
55%
15198
28%
28410

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
33%
717
22%
2327
11%
716
47%
716
25%
1398
January16th to endNight
29%
768
25%
2496
13%
768
44%
768
25%
1541
February1st to 15thNight
31%
702
22%
2256
10%
701
46%
701
26%
1372
February16th to endNight
26%
631
27%
1839
10%
631
43%
631
29%
1121
March1st to 15thNight
33%
720
26%
1980
13%
720
44%
720
31%
1229
March16th to endNight
36%
720
19%
1980
9%
720
45%
720
29%
1270
April1st to 15thNight
37%
658
25%
1748
11%
658
46%
658
32%
1119
April16th to endNight
43%
620
24%
1610
12%
620
49%
620
34%
998
May1st to 15thNight
45%
495
19%
1485
10%
495
52%
495
29%
934
May16th to endNight
62%
513
18%
1539
13%
513
65%
513
29%
966
June1st to 15thNight
60%
495
15%
1485
13%
495
62%
495
24%
1012
June16th to endNight
68%
495
15%
1485
13%
495
69%
495
27%
976
July1st to 15thNight
62%
465
11%
1395
10%
465
63%
465
24%
966
July16th to endNight
71%
522
13%
1469
10%
489
72%
489
25%
997
August1st to 15thNight
69%
494
17%
1474
17%
491
70%
491
27%
960
August16th to endNight
63%
632
15%
1682
13%
632
64%
632
25%
1202
September1st to 15thNight
66%
660
22%
1776
18%
660
67%
660
32%
1146
September16th to endNight
50%
657
16%
1815
12%
657
53%
657
22%
1294
October1st to 15thNight
51%
660
29%
1950
27%
660
57%
660
33%
1166
October16th to endNight
52%
704
34%
2112
25%
704
65%
704
36%
1179
November1st to 15thNight
51%
700
30%
2101
22%
700
62%
700
38%
1168
November16th to endNight
45%
720
27%
2332
20%
720
55%
720
30%
1354
December1st to 15thNight
42%
720
23%
2340
17%
720
52%
720
25%
1444
December16th to endNight
35%
768
23%
2496
17%
768
45%
768
22%
1598

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
13%5%245%3445%7%42%
45642
Night
12%5%2442445%7%45%
45372
TransparencyDay
39%6%11%19%18%4
45343
Night
37%6%11%19%19%6%
45175
SeeingDay
15%5%20%25%21%11%
4961
Night
15%6%24%31%19%2
15243

By Month

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
17%7%25%423435%44%
1611
16th to endDay
15%424323446%48%
1728
February1st to 15thDay
16%5%24423346%46%
1601
16th to endDay
17%325%42334448%
1632
March1st to 15thDay
15%323413245%51%
1980
16th to endDay
16%6%23324446%43%
1974
April1st to 15thDay
11%323424448%49%
1870
16th to endDay
11%5%24425%45%6%47%
2029
May1st to 15thDay
11%5%25%5%46%46%7%39%
2136
16th to endDay
10%5%26%6%35%6%5%8%39%
2223
June1st to 15thDay
10%425%5%5%5%6%6%8%38%
2145
16th to endDay
5%3246%47%7%8%11%38%
2145
July1st to 15thDay
9%6%26%6%47%6%7%10%31%
2145
16th to endDay
7%426%7%5%9%7%9%11%30%
2283
August1st to 15thDay
11%5%25%6%45%7%7%11%30%
2145
16th to endDay
13%425%7%45%6%7%9%32%
2157
September1st to 15thDay
9%5%15%6%35%6%6%8%41%
1852
16th to endDay
20%6%35%5%2435%6%36%
1815
October1st to 15thDay
17%413314335%51%
1680
16th to endDay
12%224322325%57%
1760
November1st to 15thDay
12%423212236%57%
1757
16th to endDay
13%423423345%50%
1626
December1st to 15thDay
14%7%25%5%2345%6%42%
1620
16th to endDay
19%6%24433347%41%
1728
January1st to 15thNight
15%6%23423445%48%
2327
16th to endNight
17%5%24423345%46%
2496
February1st to 15thNight
15%5%23423445%48%
2249
16th to endNight
14%423434445%49%
1839
March1st to 15thNight
12%424424445%49%
1980
16th to endNight
14%415%42345%6%45%
1980
April1st to 15thNight
11%5%23424347%47%
1748
16th to endNight
10%4235%2445%7%49%
1610
May1st to 15thNight
10%435%5%245%6%8%42%
1484
16th to endNight
9%3145%36%46%9%44%
1538
June1st to 15thNight
10%5%46%5%46%5%6%9%35%
1485
16th to endNight
5%416%6%46%6%9%10%38%
1485
July1st to 15thNight
7%5%37%6%35%6%8%11%31%
1485
16th to endNight
6%435%7%36%6%8%12%34%
1577
August1st to 15thNight
10%425%5%35%5%8%11%37%
1485
16th to endNight
10%6%36%6%36%6%7%11%32%
1682
September1st to 15thNight
9%5%245%335%6%9%44%
1776
16th to endNight
18%6%25%5%35%445%38%
1815
October1st to 15thNight
17%423322336%51%
1950
16th to endNight
11%42332324458%
2112
November1st to 15thNight
11%5%23222236%57%
2101
16th to endNight
13%423323345%51%
2332
December1st to 15thNight
15%5%34323445%46%
2340
16th to endNight
18%6%24423346%42%
2496

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%7%15%22%6%
1612
16th to endDay
37%45%20%23%9%
1728
February1st to 15thDay
39%37%20%23%4
1603
16th to endDay
38%37%23%21%5%
1632
March1st to 15thDay
35%48%21%23%6%
1980
16th to endDay
41%5%10%18%19%4
1975
April1st to 15thDay
32%49%23%23%5%
1870
16th to endDay
35%6%9%16%23%8%
2029
May1st to 15thDay
41%7%14%18%16%1
2136
16th to endDay
39%8%13%22%14%1
2227
June1st to 15thDay
39%8%16%23%10%1
2145
16th to endDay
34%10%15%22%13%2
2145
July1st to 15thDay
42%11%16%17%9%2
2006
16th to endDay
40%14%19%17%7%
2128
August1st to 15thDay
43%11%15%17%11%1
2132
16th to endDay
43%10%14%19%10%1
2157
September1st to 15thDay
37%9%14%18%17%3
1852
16th to endDay
47%6%8%16%15%5%
1815
October1st to 15thDay
36%47%20%25%4
1680
16th to endDay
31%26%19%28%10%
1760
November1st to 15thDay
30%38%17%30%10%
1757
16th to endDay
35%49%18%23%8%
1626
December1st to 15thDay
42%49%19%18%5%
1620
16th to endDay
44%39%18%17%6%
1728
January1st to 15thNight
38%410%14%24%6%
2327
16th to endNight
40%35%18%22%8%
2496
February1st to 15thNight
38%37%18%24%7%
2258
16th to endNight
36%49%21%22%6%
1839
March1st to 15thNight
35%49%20%21%8%
1980
16th to endNight
38%5%12%17%20%5%
1980
April1st to 15thNight
35%5%7%21%21%7%
1748
16th to endNight
33%5%9%20%20%10%
1610
May1st to 15thNight
37%7%14%21%17%2
1485
16th to endNight
34%9%14%27%12%1
1540
June1st to 15thNight
42%8%15%21%9%1
1485
16th to endNight
35%12%15%22%11%2
1485
July1st to 15thNight
41%11%18%16%9%3
1395
16th to endNight
36%13%19%18%9%1
1469
August1st to 15thNight
37%9%19%21%9%2
1474
16th to endNight
42%10%17%19%8%
1682
September1st to 15thNight
34%8%16%19%14%5%
1776
16th to endNight
47%7%11%13%16%3
1815
October1st to 15thNight
35%49%19%24%6%
1950
16th to endNight
30%36%20%26%12%
2112
November1st to 15thNight
30%37%15%29%14%
2101
16th to endNight
34%46%17%26%10%
2332
December1st to 15thNight
39%5%9%19%18%7%
2340
16th to endNight
43%49%17%18%7%
2496

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
24%15%30%24%5%
90
16th to endDay
14%27%38%15%4
96
February1st to 15thDay
18%20%51%8%1
90
16th to endDay
15%15%42%20%5%
133
March1st to 15thDay
14%12%34%31%5%1
270
16th to endDay
19%7%34%26%10%1
238
April1st to 15thDay
17%12%29%26%10%3
210
16th to endDay
12%6%25%26%20%7%
210
May1st to 15thDay
12%431%24%19%7%
228
16th to endDay
15%213%18%31%19%
267
June1st to 15thDay
14%112%27%28%16%
255
16th to endDay
6%112%25%35%18%
255
July1st to 15thDay
9%13%22%32%21%
245
16th to endDay
6%16%23%39%22%
270
August1st to 15thDay
15%7%23%26%25%
253
16th to endDay
14%16%27%25%25%
268
September1st to 15thDay
11%7%28%30%21%
255
16th to endDay
27%316%20%24%8%
254
October1st to 15thDay
22%417%29%20%5%
255
16th to endDay
11%5%23%27%23%8%
272
November1st to 15thDay
19%424%27%18%6%
265
16th to endDay
7%11%22%37%16%4
96
December1st to 15thDay
23%11%33%24%6%1
90
16th to endDay
30%11%33%15%9%
96
January1st to 15thNight
17%11%33%29%8%
720
16th to endNight
20%9%36%30%3
768
February1st to 15thNight
19%10%35%31%2
704
16th to endNight
15%10%42%26%4
631
March1st to 15thNight
14%9%38%29%7%
720
16th to endNight
17%7%33%30%10%
720
April1st to 15thNight
15%12%32%30%9%
658
16th to endNight
12%7%30%34%14%
620
May1st to 15thNight
13%5%29%33%16%1
495
16th to endNight
10%118%34%32%2
515
June1st to 15thNight
12%115%38%27%4
495
16th to endNight
6%211%36%34%8%
495
July1st to 15thNight
9%11%36%36%5%
465
16th to endNight
7%8%32%44%6%
522
August1st to 15thNight
11%7%27%46%5%
494
16th to endNight
13%18%30%40%5%
632
September1st to 15thNight
11%18%31%40%6%
660
16th to endNight
22%215%29%27%2
657
October1st to 15thNight
20%320%26%25%3
660
16th to endNight
13%6%24%29%23%2
704
November1st to 15thNight
15%5%23%34%17%3
700
16th to endNight
14%8%28%30%15%2
720
December1st to 15thNight
17%7%26%35%11%1
720
16th to endNight
22%10%26%31%9%
768
Page generated at 2017-03-20 08:18:33. Version ac04

Copyright 2017 A. Danko


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