Waltz Road
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Waltz Road clear sky chart from 2005-11-05 to 2017-09-22.

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
68%
15239
29%
46937
25%
15202
72%
15202
44%
24388

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
64%
716
18%
2464
20%
716
66%
716
30%
1429
January16th to endNight
59%
768
25%
2496
26%
768
62%
768
29%
1499
February1st to 15thNight
58%
697
23%
2283
23%
696
63%
696
27%
1388
February16th to endNight
56%
632
27%
1895
24%
632
62%
632
32%
1145
March1st to 15thNight
57%
720
17%
2049
17%
720
59%
720
28%
1337
March16th to endNight
52%
768
22%
2064
15%
768
57%
768
33%
1304
April1st to 15thNight
57%
719
23%
1799
12%
719
61%
719
37%
1159
April16th to endNight
63%
720
26%
1800
12%
720
67%
720
49%
1014
May1st to 15thNight
67%
560
30%
1640
21%
560
72%
560
58%
761
May16th to endNight
70%
374
28%
1496
29%
374
76%
374
49%
595
June1st to 15thNight
67%
360
27%
1440
30%
360
75%
360
50%
568
June16th to endNight
76%
360
36%
1440
43%
360
85%
360
67%
471
July1st to 15thNight
86%
340
36%
1360
44%
340
91%
340
77%
410
July16th to endNight
87%
505
41%
1534
37%
472
91%
472
82%
536
August1st to 15thNight
79%
561
39%
1634
27%
558
84%
558
75%
662
August16th to endNight
90%
764
45%
1910
28%
764
92%
764
84%
842
September1st to 15thNight
88%
720
42%
1800
28%
720
91%
720
81%
810
September16th to endNight
82%
683
44%
1854
37%
683
87%
683
74%
812
October1st to 15thNight
75%
660
32%
1980
33%
660
79%
660
53%
939
October16th to endNight
74%
704
36%
2112
37%
704
78%
704
49%
1062
November1st to 15thNight
72%
700
28%
2243
30%
700
76%
700
43%
1154
November16th to endNight
65%
720
25%
2436
25%
720
69%
720
35%
1313
December1st to 15thNight
57%
720
21%
2520
21%
720
62%
720
26%
1491
December16th to endNight
51%
768
21%
2688
20%
768
57%
768
23%
1687

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
8%212212235%65%
47953
Night
10%312212335%62%
47121
TransparencyDay
23%38%20%24%19%
47636
Night
25%39%19%23%18%
46938
SeeingDay
9%314%24%29%17%
5894
Night
11%213%36%31%5%
15252

By Month

Percentage Cloud Cover SW (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
18%413313445%47%
1472
16th to endDay
18%6%24423336%43%
1728
February1st to 15thDay
18%5%24413247%44%
1582
16th to endDay
18%5%13422446%44%
1579
March1st to 15thDay
17%433325%45%6%42%
1908
16th to endDay
16%41442445%7%44%
2160
April1st to 15thDay
14%5%2342435%7%45%
2149
16th to endDay
8%212213346%63%
2160
May1st to 15thDay
411222236%71%
2307
16th to endDay
5%213222346%64%
2615
June1st to 15thDay
5%212212236%69%
2520
16th to endDay
11112384%
2520
July1st to 15thDay
1112288%
2520
16th to endDay
112287%
2525
August1st to 15thDay
1111387%
2316
16th to endDay
111388%
2292
September1st to 15thDay
1122484%
2160
16th to endDay
3111122479%
1917
October1st to 15thDay
5%12212346%69%
1650
16th to endDay
8%313213345%61%
1760
November1st to 15thDay
9%212325%347%55%
1614
16th to endDay
14%413424346%50%
1523
December1st to 15thDay
18%5%26%42343443%
1440
16th to endDay
20%6%25%5%22345%40%
1536
January1st to 15thNight
16%414313347%49%
2464
16th to endNight
16%423423336%48%
2496
February1st to 15thNight
17%41332435%7%44%
2271
16th to endNight
18%41331235%6%49%
1895
March1st to 15thNight
17%5%2433445%6%42%
2049
16th to endNight
16%312414347%49%
2064
April1st to 15thNight
11%42343445%7%47%
1799
16th to endNight
8%213212336%63%
1800
May1st to 15thNight
421112336%70%
1640
16th to endNight
411212447%68%
1496
June1st to 15thNight
4212213235%71%
1440
16th to endNight
1111112382%
1440
July1st to 15thNight
11288%
1440
16th to endNight
12288%
1641
August1st to 15thNight
11111212383%
1643
16th to endNight
1112386%
1910
September1st to 15thNight
111111386%
1800
16th to endNight
11111225%80%
1854
October1st to 15thNight
6%11121224469%
1980
16th to endNight
6%22322336%64%
2112
November1st to 15thNight
10%21321235%7%59%
2243
16th to endNight
12%322322446%55%
2436
December1st to 15thNight
21%412312346%47%
2520
16th to endNight
23%423323246%43%
2688

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
39%413%16%20%4
1472
16th to endDay
44%37%16%16%10%
1728
February1st to 15thDay
41%49%20%17%5%
1582
16th to endDay
40%5%11%26%13%3
1579
March1st to 15thDay
42%5%11%20%13%6%
1908
16th to endDay
39%7%13%18%17%3
2160
April1st to 15thDay
38%410%24%16%4
2149
16th to endDay
22%412%25%27%7%
2160
May1st to 15thDay
15%29%29%31%11%
2307
16th to endDay
20%411%29%24%9%
2619
June1st to 15thDay
18%49%23%24%20%
2520
16th to endDay
6%1414%38%34%
2520
July1st to 15thDay
5%1210%28%52%
2371
16th to endDay
5%1210%24%55%
2369
August1st to 15thDay
5%1212%30%46%
2300
16th to endDay
4214%38%39%
2292
September1st to 15thDay
6%1413%34%38%
2160
16th to endDay
12%25%22%34%23%
1917
October1st to 15thDay
16%38%24%28%18%
1650
16th to endDay
25%38%23%25%12%
1760
November1st to 15thDay
28%5%12%29%17%6%
1614
16th to endDay
36%410%23%18%5%
1523
December1st to 15thDay
45%5%8%20%17%3
1440
16th to endDay
45%5%9%18%17%4
1536
January1st to 15thNight
35%413%20%16%8%
2464
16th to endNight
38%39%15%17%14%
2496
February1st to 15thNight
39%49%20%18%7%
2283
16th to endNight
35%5%9%25%20%4
1895
March1st to 15thNight
40%5%11%18%17%6%
2049
16th to endNight
35%5%10%20%19%7%
2064
April1st to 15thNight
34%5%13%21%17%8%
1799
16th to endNight
22%413%22%26%10%
1800
May1st to 15thNight
14%410%25%28%16%
1641
16th to endNight
15%316%30%22%11%
1496
June1st to 15thNight
16%312%24%23%20%
1440
16th to endNight
9%1313%33%38%
1440
July1st to 15thNight
5%118%28%54%
1360
16th to endNight
5%211%23%56%
1534
August1st to 15thNight
8%312%28%46%
1634
16th to endNight
5%1211%36%42%
1910
September1st to 15thNight
7%1411%36%39%
1800
16th to endNight
9%16%19%32%30%
1854
October1st to 15thNight
18%37%20%27%22%
1980
16th to endNight
21%36%23%25%18%
2112
November1st to 15thNight
25%312%26%20%10%
2243
16th to endNight
30%48%25%22%8%
2436
December1st to 15thNight
39%311%20%18%6%
2520
16th to endNight
43%410%15%18%7%
2688

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
34%214%22%20%8%
100
16th to endDay
20%5%16%19%21%15%
256
February1st to 15thDay
21%317%15%25%16%
237
16th to endDay
22%6%16%21%19%13%
238
March1st to 15thDay
21%9%20%17%21%10%
270
16th to endDay
19%7%20%20%21%9%
288
April1st to 15thDay
18%8%19%26%17%10%
269
16th to endDay
9%9%23%24%20%12%
270
May1st to 15thDay
5%423%27%24%14%
288
16th to endDay
6%316%23%27%23%
330
June1st to 15thDay
5%419%24%33%11%
315
16th to endDay
110%25%41%20%
315
July1st to 15thDay
7%28%43%19%
305
16th to endDay
6%28%40%24%
327
August1st to 15thDay
18%32%36%20%
315
16th to endDay
5%26%39%27%
332
September1st to 15thDay
19%24%38%26%
315
16th to endDay
2216%22%26%28%
280
October1st to 15thDay
6%318%25%23%23%
255
16th to endDay
12%411%26%29%15%
272
November1st to 15thDay
13%10%20%35%18%
120
16th to endDay
19%15%28%34%2
73
December1st to 15thDay
35%6%16%25%16%
60
16th to endDay
15%315%25%35%4
64
January1st to 15thNight
17%28%33%30%7%
720
16th to endNight
19%28%35%26%7%
768
February1st to 15thNight
19%311%33%27%3
704
16th to endNight
19%316%34%21%5%
632
March1st to 15thNight
17%313%31%28%4
720
16th to endNight
18%319%30%25%2
768
April1st to 15thNight
12%320%34%25%3
719
16th to endNight
9%5%18%32%30%4
720
May1st to 15thNight
6%121%37%28%3
561
16th to endNight
5%318%41%30%1
375
June1st to 15thNight
4121%42%29%
360
16th to endNight
216%41%37%1
360
July1st to 15thNight
11%54%32%
340
16th to endNight
18%49%37%2
505
August1st to 15thNight
214%46%33%1
561
16th to endNight
17%45%43%2
764
September1st to 15thNight
18%33%51%5%
720
16th to endNight
213%33%40%9%
683
October1st to 15thNight
7%211%36%32%9%
660
16th to endNight
6%211%33%36%9%
704
November1st to 15thNight
10%110%35%33%8%
700
16th to endNight
13%212%36%27%7%
720
December1st to 15thNight
22%39%33%24%6%
720
16th to endNight
24%314%31%22%3
768
Page generated at 2017-09-23 03:43:43. Version ac04

Copyright 2017 A. Danko


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