Tanaeum Ridge and Peoh Point
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tanaeum Ridge and Peoh Point clear sky chart from 2005-11-05 to 2017-08-12.

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
35%
14382
14%
46498
9%
14355
43%
14355
19%
30321

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
29%
717
8%
2506
7%
716
33%
716
9%
1915
January16th to endNight
35%
768
10%
2688
9%
768
39%
768
12%
1944
February1st to 15thNight
31%
698
9%
2288
6%
697
36%
697
13%
1683
February16th to endNight
36%
632
13%
1972
9%
632
42%
632
16%
1388
March1st to 15thNight
31%
720
10%
2113
5%
720
37%
720
14%
1552
March16th to endNight
29%
768
10%
2032
3%
768
33%
768
15%
1499
April1st to 15thNight
30%
719
12%
1799
4%
719
34%
719
18%
1311
April16th to endNight
30%
580
13%
1660
5%
580
37%
580
19%
1131
May1st to 15thNight
37%
359
18%
1439
16%
359
49%
359
21%
828
May16th to endNight
37%
375
9%
1496
10%
374
45%
374
17%
932
June1st to 15thNight
30%
360
9%
1440
4%
360
38%
360
19%
840
June16th to endNight
30%
360
10%
1440
7%
360
40%
360
23%
756
July1st to 15thNight
42%
340
16%
1360
11%
340
57%
340
46%
537
July16th to endNight
41%
376
25%
1416
20%
354
65%
354
52%
515
August1st to 15thNight
53%
395
29%
1443
20%
393
71%
393
56%
558
August16th to endNight
47%
627
28%
1677
13%
627
57%
627
49%
857
September1st to 15thNight
54%
660
29%
1650
12%
660
61%
660
54%
850
September16th to endNight
48%
656
25%
1790
16%
656
55%
656
37%
1025
October1st to 15thNight
43%
660
18%
1980
14%
660
49%
660
27%
1222
October16th to endNight
40%
704
14%
2207
9%
704
47%
704
18%
1516
November1st to 15thNight
32%
700
11%
2374
6%
700
38%
700
12%
1699
November16th to endNight
30%
720
10%
2520
5%
720
37%
720
12%
1839
December1st to 15thNight
28%
720
11%
2520
8%
720
33%
720
11%
1873
December16th to endNight
19%
768
8%
2688
3%
768
25%
768
7%
2051

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
7%7%36%6%35%5%6%7%39%
47498
Night
7%7%36%6%35%5%6%8%38%
46666
Cloud CoverDay
6%6%35%5%35%5%6%8%42%
47498
Night
6%7%35%5%35%5%6%8%42%
46670
TransparencyDay
37%11%14%21%12%2
47169
Night
37%11%16%21%10%2
46499
SeeingDay
12%24%34%20%6%1
5328
Night
10%17%29%27%12%2
14392

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 15thDay
9%11%49%6%45%7%7%9%23%
1432
16th to endDay
8%12%46%7%35%5%6%9%28%
1536
February1st to 15thDay
11%11%5%8%7%46%5%7%8%23%
1576
16th to endDay
8%11%48%7%5%7%6%6%7%26%
1502
March1st to 15thDay
10%12%49%8%47%5%6%7%21%
1845
16th to endDay
8%11%5%10%10%6%6%7%7%7%17%
2191
April1st to 15thDay
8%12%410%9%48%5%5%7%22%
2149
16th to endDay
5%9%48%7%46%6%7%8%30%
2297
May1st to 15thDay
7%6%37%6%47%5%7%9%36%
2511
16th to endDay
11%8%36%7%45%6%6%8%31%
2615
June1st to 15thDay
8%5%36%6%45%5%7%8%38%
2520
16th to endDay
6%4246%46%5%6%7%44%
2520
July1st to 15thDay
21332445%6%64%
2520
16th to endDay
3112213345%70%
2657
August1st to 15thDay
111222335%7%67%
2423
16th to endDay
2214434447%60%
2172
September1st to 15thDay
3212323447%63%
1980
16th to endDay
6%426%6%35%5%6%7%46%
1837
October1st to 15thDay
10%7%16%6%246%5%7%40%
1650
16th to endDay
13%8%36%6%45%5%6%7%31%
1664
November1st to 15thDay
8%8%5%11%8%46%5%8%8%24%
1485
16th to endDay
10%14%5%8%6%45%46%7%25%
1440
December1st to 15thDay
9%12%5%10%7%45%5%6%8%25%
1440
16th to endDay
11%12%410%8%35%5%6%7%23%
1536
January1st to 15thNight
11%9%49%6%46%6%6%10%24%
2506
16th to endNight
9%9%37%6%47%6%6%9%28%
2688
February1st to 15thNight
11%12%5%6%5%35%46%9%28%
2276
16th to endNight
8%9%46%6%45%6%6%8%32%
1972
March1st to 15thNight
9%8%47%7%47%6%6%8%29%
2113
16th to endNight
7%8%47%8%46%7%10%9%25%
2028
April1st to 15thNight
6%6%37%7%48%8%7%9%30%
1799
16th to endNight
5%6%36%8%36%7%9%9%32%
1660
May1st to 15thNight
6%425%6%25%7%7%8%41%
1439
16th to endNight
7%5%26%5%48%6%7%9%34%
1496
June1st to 15thNight
5%417%6%35%5%7%8%42%
1440
16th to endNight
4425%5%26%5%7%7%48%
1440
July1st to 15thNight
11122335%7%69%
1440
16th to endNight
11212336%75%
1512
August1st to 15thNight
11212348%72%
1451
16th to endNight
111332345%7%64%
1677
September1st to 15thNight
3212212346%69%
1650
16th to endNight
4325%4235%6%9%51%
1790
October1st to 15thNight
8%5%26%5%345%5%7%44%
1980
16th to endNight
10%7%26%5%36%5%7%10%32%
2207
November1st to 15thNight
11%9%36%5%46%6%7%9%28%
2374
16th to endNight
8%11%5%8%6%46%5%6%8%27%
2520
December1st to 15thNight
10%10%5%8%8%46%46%8%27%
2520
16th to endNight
11%15%6%10%6%345%5%8%22%
2688

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
10%10%5%7%8%36%6%7%10%22%
1432
16th to endDay
9%11%5%5%6%35%7%7%9%28%
1536
February1st to 15thDay
10%12%37%6%26%7%7%8%26%
1576
16th to endDay
7%10%47%7%36%7%6%8%30%
1502
March1st to 15thDay
9%11%48%7%5%7%6%6%8%24%
1845
16th to endDay
7%9%5%9%8%5%7%7%6%9%23%
2191
April1st to 15thDay
7%9%47%7%47%6%8%7%28%
2149
16th to endDay
5%6%36%5%46%7%7%9%37%
2297
May1st to 15thDay
6%5%25%5%36%5%7%10%41%
2511
16th to endDay
9%5%26%6%35%6%7%8%36%
2615
June1st to 15thDay
7%325%5%45%6%6%7%45%
2520
16th to endDay
5%315%5%35%46%8%49%
2520
July1st to 15thDay
112324336%68%
2520
16th to endDay
2112212335%72%
2657
August1st to 15thDay
11222335%6%70%
2423
16th to endDay
1213433447%62%
2172
September1st to 15thDay
3212322346%67%
1980
16th to endDay
6%3145%35%5%6%6%50%
1837
October1st to 15thDay
9%5%25%6%3446%8%42%
1650
16th to endDay
10%7%36%5%45%6%6%8%34%
1664
November1st to 15thDay
8%7%39%8%46%7%7%8%28%
1485
16th to endDay
10%11%5%7%6%36%5%6%8%27%
1440
December1st to 15thDay
8%12%5%9%6%35%5%7%7%27%
1440
16th to endDay
12%12%5%8%5%35%5%6%8%26%
1536
January1st to 15thNight
10%10%5%8%7%36%6%6%10%23%
2506
16th to endNight
9%10%37%6%46%7%7%10%25%
2688
February1st to 15thNight
9%11%5%7%6%345%6%9%31%
2276
16th to endNight
7%8%45%5%35%6%7%7%37%
1972
March1st to 15thNight
8%8%36%7%36%6%7%8%32%
2113
16th to endNight
6%7%35%6%47%6%9%10%32%
2032
April1st to 15thNight
6%5%26%6%46%6%7%9%38%
1799
16th to endNight
45%35%6%35%6%7%10%41%
1660
May1st to 15thNight
5%325%5%35%5%6%8%48%
1439
16th to endNight
5%5%25%6%46%7%8%8%40%
1496
June1st to 15thNight
5%22445%6%5%7%7%47%
1440
16th to endNight
2415%4345%6%7%53%
1440
July1st to 15thNight
111122347%72%
1440
16th to endNight
1112236%78%
1512
August1st to 15thNight
111235%6%76%
1451
16th to endNight
111232235%8%67%
1677
September1st to 15thNight
212212237%72%
1650
16th to endNight
3315%32336%10%55%
1790
October1st to 15thNight
8%415%5%3346%6%48%
1980
16th to endNight
9%6%26%5%35%6%7%9%36%
2207
November1st to 15thNight
10%8%25%6%35%6%7%8%33%
2374
16th to endNight
8%10%47%7%35%6%7%7%30%
2520
December1st to 15thNight
9%10%5%7%6%46%5%6%7%30%
2520
16th to endNight
11%15%6%8%6%245%5%7%26%
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
55%14%11%12%41
1432
16th to endDay
49%11%15%14%7%
1536
February1st to 15thDay
53%14%16%13%2
1576
16th to endDay
47%15%15%16%5%
1502
March1st to 15thDay
55%11%14%12%5%
1845
16th to endDay
54%16%14%12%2
2191
April1st to 15thDay
50%13%15%15%4
2149
16th to endDay
39%17%17%19%5%
2297
May1st to 15thDay
35%11%17%24%10%1
2511
16th to endDay
40%14%19%20%5%
2619
June1st to 15thDay
33%12%16%24%10%2
2520
16th to endDay
28%11%16%27%14%1
2520
July1st to 15thDay
17%6%10%26%28%10%
2371
16th to endDay
14%48%26%30%14%
2490
August1st to 15thDay
13%6%10%34%26%8%
2406
16th to endDay
19%7%12%29%26%4
2172
September1st to 15thDay
18%5%12%28%28%5%
1980
16th to endDay
30%9%16%22%16%5%
1837
October1st to 15thDay
37%9%15%25%10%
1650
16th to endDay
44%10%15%20%8%
1664
November1st to 15thDay
50%15%13%16%31
1485
16th to endDay
53%12%13%15%5%
1440
December1st to 15thDay
53%11%13%16%5%
1440
16th to endDay
53%14%12%13%5%
1536
January1st to 15thNight
54%12%14%13%4
2506
16th to endNight
50%10%16%14%6%1
2688
February1st to 15thNight
48%12%18%15%4
2288
16th to endNight
42%13%17%20%5%
1972
March1st to 15thNight
46%12%17%17%5%
2113
16th to endNight
41%16%19%19%2
2032
April1st to 15thNight
39%16%17%21%6%
1799
16th to endNight
32%18%20%21%6%
1660
May1st to 15thNight
30%12%15%30%9%1
1440
16th to endNight
35%14%22%22%5%
1496
June1st to 15thNight
30%13%18%26%9%
1440
16th to endNight
25%11%18%29%12%2
1440
July1st to 15thNight
11%7%15%32%23%9%
1360
16th to endNight
7%6%10%30%28%15%
1416
August1st to 15thNight
8%6%13%33%27%9%
1443
16th to endNight
14%7%14%33%24%4
1677
September1st to 15thNight
13%6%14%28%31%5%
1650
16th to endNight
24%8%19%25%14%6%
1790
October1st to 15thNight
33%9%14%27%13%1
1980
16th to endNight
40%13%14%21%9%
2207
November1st to 15thNight
45%13%16%17%41
2374
16th to endNight
49%12%14%16%7%
2520
December1st to 15thNight
50%13%13%18%4
2520
16th to endNight
56%10%16%11%5%
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
16%11%15%31%18%6%
60
16th to endDay
25%14%25%20%10%4
64
February1st to 15thDay
19%23%34%18%31
236
16th to endDay
19%27%32%15%4
225
March1st to 15thDay
20%38%28%12%1
270
16th to endDay
21%36%29%8%3
288
April1st to 15thDay
15%35%28%14%5%
269
16th to endDay
15%37%30%10%32
270
May1st to 15thDay
19%24%31%19%31
288
16th to endDay
11%19%31%25%9%2
330
June1st to 15thDay
9%24%41%19%5%
315
16th to endDay
8%28%37%18%6%
315
July1st to 15thDay
115%47%29%4
305
16th to endDay
320%41%24%7%
327
August1st to 15thDay
5%12%38%29%10%4
300
16th to endDay
5%14%38%27%10%2
268
September1st to 15thDay
7%25%31%25%9%1
255
16th to endDay
9%18%39%27%5%
255
October1st to 15thDay
18%22%31%20%6%1
255
16th to endDay
17%19%28%26%43
176
November1st to 15thDay
12%24%38%21%2
73
16th to endDay
20%18%21%20%13%6%
60
December1st to 15thDay
13%30%38%16%1
60
16th to endDay
9%17%31%26%14%1
64
January1st to 15thNight
16%18%22%26%14%1
720
16th to endNight
14%14%25%27%14%3
768
February1st to 15thNight
13%15%27%29%11%1
704
16th to endNight
13%20%21%28%14%1
632
March1st to 15thNight
13%18%29%28%9%1
720
16th to endNight
10%23%29%25%9%1
768
April1st to 15thNight
9%22%31%25%9%1
719
16th to endNight
7%24%33%21%10%2
580
May1st to 15thNight
7%22%30%25%11%1
360
16th to endNight
7%14%34%29%12%1
375
June1st to 15thNight
7%18%40%23%8%
360
16th to endNight
5%24%36%22%8%1
360
July1st to 15thNight
212%41%34%9%
340
16th to endNight
114%41%32%9%1
376
August1st to 15thNight
18%35%34%16%3
395
16th to endNight
314%32%29%16%3
627
September1st to 15thNight
313%26%27%22%7%
660
16th to endNight
5%16%26%28%18%5%
656
October1st to 15thNight
11%14%26%26%17%4
660
16th to endNight
13%14%24%28%14%4
704
November1st to 15thNight
14%18%27%29%8%
700
16th to endNight
14%17%27%21%15%3
720
December1st to 15thNight
13%17%31%22%14%
720
16th to endNight
19%22%26%26%5%
768
Page generated at 2017-08-13 11:16:28. Version ac04

Copyright 2017 A. Danko


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