New River
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the New River clear sky chart from 2005-11-05 to 2017-10-06.

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
76%
15740
37%
47130
32%
15701
81%
15701
55%
22303

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
66%
719
34%
2327
31%
716
74%
716
45%
1129
January16th to endNight
60%
768
37%
2496
34%
768
70%
768
42%
1279
February1st to 15thNight
71%
698
36%
2175
32%
698
81%
698
52%
1022
February16th to endNight
66%
632
34%
1895
35%
632
71%
632
45%
991
March1st to 15thNight
68%
720
39%
1983
31%
720
76%
720
57%
977
March16th to endNight
74%
768
39%
2112
30%
768
81%
768
61%
1001
April1st to 15thNight
67%
716
32%
1975
21%
716
74%
716
55%
980
April16th to endNight
69%
540
45%
1671
35%
540
79%
540
70%
650
May1st to 15thNight
76%
539
39%
1619
32%
539
80%
539
65%
686
May16th to endNight
79%
561
40%
1684
32%
561
83%
561
72%
679
June1st to 15thNight
85%
540
34%
1620
31%
540
86%
540
72%
659
June16th to endNight
91%
540
35%
1620
32%
540
91%
540
76%
639
July1st to 15thNight
87%
510
26%
1530
22%
510
87%
510
51%
757
July16th to endNight
83%
564
27%
1593
23%
531
84%
531
42%
887
August1st to 15thNight
86%
539
29%
1611
25%
536
86%
536
48%
822
August16th to endNight
85%
654
34%
1865
31%
654
85%
654
45%
1026
September1st to 15thNight
84%
720
32%
1980
28%
720
85%
720
52%
1042
September16th to endNight
86%
716
44%
1980
36%
716
89%
716
69%
874
October1st to 15thNight
77%
684
41%
1950
34%
684
81%
684
64%
880
October16th to endNight
82%
704
43%
2112
37%
704
87%
704
64%
917
November1st to 15thNight
81%
700
41%
2156
38%
700
86%
700
63%
920
November16th to endNight
74%
720
40%
2340
39%
720
80%
720
55%
1037
December1st to 15thNight
73%
720
36%
2340
35%
720
79%
720
46%
1130
December16th to endNight
63%
768
34%
2496
33%
768
69%
768
38%
1319

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
3212213346%68%
48068
Night
4212213345%68%
47326
TransparencyDay
17%2412%25%37%
47763
Night
17%3411%24%38%
47132
SeeingDay
46%22%38%22%5%
5549
Night
4211%38%37%5%
15750

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
6%31331324466%
1611
16th to endDay
8%212212236%64%
1728
February1st to 15thDay
4312323236%65%
1685
16th to endDay
8%323313336%60%
1579
March1st to 15thDay
5%212212246%66%
1977
16th to endDay
3212213325%70%
2112
April1st to 15thDay
3112213347%68%
1973
16th to endDay
2112123477%
2286
May1st to 15thDay
111112235%77%
2331
16th to endDay
21121112479%
2429
June1st to 15thDay
11111112482%
2340
16th to endDay
1111212383%
2340
July1st to 15thDay
221332445%8%61%
2340
16th to endDay
5%3135%35%6%7%10%44%
2467
August1st to 15thDay
3223325%5%6%8%56%
2340
16th to endDay
32123245%6%7%61%
2333
September1st to 15thDay
4312223436%64%
1980
16th to endDay
11111122381%
1980
October1st to 15thDay
22121212477%
1807
16th to endDay
111212235%76%
1760
November1st to 15thDay
11221234474%
1702
16th to endDay
5%111112235%72%
1620
December1st to 15thDay
6%413413345%60%
1620
16th to endDay
8%414312346%58%
1728
January1st to 15thNight
6%31321333466%
2327
16th to endNight
9%41332212463%
2496
February1st to 15thNight
5%312112245%68%
2164
16th to endNight
7%213324446%60%
1895
March1st to 15thNight
5%212212336%69%
1983
16th to endNight
3111213236%71%
2112
April1st to 15thNight
3113213336%67%
1975
16th to endNight
1111122382%
1671
May1st to 15thNight
121112345%75%
1619
16th to endNight
21111111382%
1684
June1st to 15thNight
11111122481%
1620
16th to endNight
111111483%
1620
July1st to 15thNight
1113325%5%6%9%59%
1620
16th to endNight
2223435%7%8%10%47%
1701
August1st to 15thNight
22124245%8%9%55%
1620
16th to endNight
124435%5%6%7%57%
1865
September1st to 15thNight
32133235%7%8%59%
1980
16th to endNight
2111232379%
1980
October1st to 15thNight
3112211235%74%
1950
16th to endNight
121111223477%
2112
November1st to 15thNight
22111333474%
2156
16th to endNight
5%21221223472%
2340
December1st to 15thNight
7%213223336%64%
2340
16th to endNight
8%324413345%58%
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
22%3313%28%29%
1612
16th to endDay
22%15%16%26%27%
1728
February1st to 15thDay
21%16%15%26%28%
1685
16th to endDay
25%2318%27%22%
1579
March1st to 15thDay
19%1210%31%34%
1977
16th to endDay
18%1312%32%31%
2112
April1st to 15thDay
16%2311%31%34%
1973
16th to endDay
11%128%26%49%
2286
May1st to 15thDay
10%139%26%48%
2331
16th to endDay
10%127%24%53%
2432
June1st to 15thDay
8%11418%66%
2340
16th to endDay
8%11412%71%
2340
July1st to 15thDay
18%5%10%15%17%32%
2201
16th to endDay
30%7%13%21%18%9%
2312
August1st to 15thDay
21%5%9%16%19%27%
2325
16th to endDay
19%5%7%17%28%21%
2333
September1st to 15thDay
20%37%14%24%29%
1980
16th to endDay
10%126%29%50%
1980
October1st to 15thDay
13%2310%27%43%
1807
16th to endDay
11%25%8%26%46%
1760
November1st to 15thDay
12%2313%31%37%
1702
16th to endDay
16%2212%24%41%
1620
December1st to 15thDay
25%35%17%24%23%
1620
16th to endDay
27%3419%27%16%
1728
January1st to 15thNight
22%2311%26%31%
2327
16th to endNight
27%2212%26%29%
2496
February1st to 15thNight
19%26%13%25%32%
2175
16th to endNight
25%25%12%27%26%
1895
March1st to 15thNight
18%138%27%39%
1983
16th to endNight
15%1312%32%34%
2112
April1st to 15thNight
18%229%29%37%
1975
16th to endNight
8%128%24%54%
1671
May1st to 15thNight
11%138%27%47%
1620
16th to endNight
9%17%22%57%
1685
June1st to 15thNight
9%12314%68%
1620
16th to endNight
8%139%75%
1620
July1st to 15thNight
17%6%10%14%16%34%
1530
16th to endNight
23%8%12%21%19%14%
1593
August1st to 15thNight
20%6%9%18%16%29%
1611
16th to endNight
23%6%6%15%21%26%
1865
September1st to 15thNight
18%6%9%17%19%28%
1980
16th to endNight
11%125%24%54%
1980
October1st to 15thNight
14%1211%26%44%
1950
16th to endNight
12%247%20%52%
2112
November1st to 15thNight
13%2211%30%39%
2156
16th to endNight
17%2410%23%42%
2340
December1st to 15thNight
22%3414%26%28%
2340
16th to endNight
28%3417%27%18%
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
28%316%36%12%2
90
16th to endDay
9%6%18%28%33%4
96
February1st to 15thDay
46%25%41%22%
200
16th to endDay
11%12%35%26%13%
238
March1st to 15thDay
6%11%25%36%16%3
270
16th to endDay
413%34%31%14%2
288
April1st to 15thDay
7%14%30%33%10%4
269
16th to endDay
420%41%22%8%2
270
May1st to 15thDay
215%31%34%13%3
288
16th to endDay
37%35%36%14%3
330
June1st to 15thDay
15%32%38%17%4
315
16th to endDay
118%47%23%7%
315
July1st to 15thDay
1112%48%29%6%
305
16th to endDay
47%39%34%13%
327
August1st to 15thDay
38%41%33%12%
315
16th to endDay
27%45%35%8%
332
September1st to 15thDay
6%114%44%26%5%
315
16th to endDay
45%21%41%21%5%
315
October1st to 15thDay
4329%37%20%3
209
16th to endDay
4311%38%39%3
96
November1st to 15thDay
3315%43%28%5%
90
16th to endDay
6%325%40%22%2
90
December1st to 15thDay
3314%38%35%4
90
16th to endDay
13%8%22%36%14%4
96
January1st to 15thNight
7%217%43%25%4
720
16th to endNight
11%317%40%23%3
768
February1st to 15thNight
6%214%46%27%2
704
16th to endNight
8%117%47%21%3
632
March1st to 15thNight
6%318%40%28%3
720
16th to endNight
4314%41%31%4
768
April1st to 15thNight
45%18%42%25%3
716
16th to endNight
15%21%40%26%4
540
May1st to 15thNight
2414%44%30%4
540
16th to endNight
2113%39%38%4
563
June1st to 15thNight
119%45%40%1
540
16th to endNight
1436%51%6%
540
July1st to 15thNight
2329%57%6%
510
16th to endNight
2220%61%12%
564
August1st to 15thNight
3119%65%10%
539
16th to endNight
2222%60%12%
654
September1st to 15thNight
35%28%54%6%
720
16th to endNight
316%38%43%6%
716
October1st to 15thNight
4210%41%37%3
684
16th to endNight
219%39%37%9%
704
November1st to 15thNight
3110%42%36%6%
700
16th to endNight
5%112%40%33%5%
720
December1st to 15thNight
8%211%41%34%1
720
16th to endNight
10%115%43%24%3
768
Page generated at 2017-10-07 11:07:56. Version ac04

Copyright 2017 A. Danko


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