Palouse Falls Star Party
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Palouse Falls Star Party clear sky chart from 2005-11-05 to

2017-09-12
.

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
49%
14527
16%
46786
14%
14499
52%
14499
23%
30421

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
32%
716
7%
2506
6%
716
34%
716
9%
2035
January16th to endNight
36%
768
6%
2688
6%
768
38%
768
9%
2147
February1st to 15thNight
43%
701
8%
2359
8%
697
45%
697
14%
1751
February16th to endNight
41%
632
15%
1895
14%
632
45%
632
18%
1364
March1st to 15thNight
41%
720
12%
2160
10%
720
45%
720
20%
1520
March16th to endNight
38%
768
11%
2013
6%
768
40%
768
19%
1485
April1st to 15thNight
41%
719
14%
1799
6%
719
43%
719
24%
1309
April16th to endNight
47%
593
18%
1673
11%
593
51%
593
29%
1078
May1st to 15thNight
53%
384
23%
1465
23%
384
62%
384
32%
747
May16th to endNight
55%
374
13%
1496
18%
374
60%
374
21%
903
June1st to 15thNight
50%
360
10%
1440
11%
360
57%
360
26%
785
June16th to endNight
54%
360
14%
1440
19%
360
59%
360
30%
734
July1st to 15thNight
69%
340
19%
1360
26%
340
76%
340
52%
524
July16th to endNight
74%
376
29%
1416
40%
354
83%
354
62%
475
August1st to 15thNight
80%
362
34%
1434
41%
360
86%
360
55%
538
August16th to endNight
74%
720
34%
1866
21%
720
78%
720
65%
907
September1st to 15thNight
75%
706
34%
1765
19%
706
78%
706
65%
878
September16th to endNight
63%
656
29%
1806
24%
656
65%
656
45%
1001
October1st to 15thNight
54%
660
20%
1933
17%
660
58%
660
33%
1167
October16th to endNight
48%
704
16%
2269
16%
704
51%
704
22%
1480
November1st to 15thNight
42%
700
13%
2275
13%
700
45%
700
17%
1604
November16th to endNight
40%
720
7%
2520
6%
720
42%
720
12%
1884
December1st to 15thNight
39%
720
8%
2520
8%
720
41%
720
11%
1986
December16th to endNight
31%
768
6%
2688
4%
768
34%
768
10%
2119

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%6%35%5%3445%7%46%
47895
Night
10%7%36%5%3445%7%41%
46953
Cloud CoverDay
8%6%35%5%2445%6%46%
47895
Night
11%7%36%5%3445%6%41%
46957
TransparencyDay
37%6%12%21%15%5%
47566
Night
42%6%13%19%13%5%
46786
SeeingDay
11%9%23%26%21%7%
5346
Night
14%7%19%32%22%3
14536

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
16%14%5%10%8%445%46%17%
1432
16th to endDay
14%16%8%12%7%45%5%45%15%
1536
February1st to 15thDay
13%12%5%9%6%46%5%46%24%
1504
16th to endDay
10%10%49%7%35%5%47%32%
1579
March1st to 15thDay
12%8%47%7%36%6%5%8%27%
1800
16th to endDay
12%7%38%7%46%7%6%6%28%
2210
April1st to 15thDay
6%6%26%6%46%6%9%9%35%
2149
16th to endDay
7%5%26%43446%7%45%
2286
May1st to 15thDay
5%414435%45%7%51%
2484
16th to endDay
6%436%5%35%6%6%8%42%
2615
June1st to 15thDay
8%425%5%245%5%7%48%
2520
16th to endDay
6%31332435%7%57%
2520
July1st to 15thDay
1112112335%74%
2520
16th to endDay
1111233478%
2657
August1st to 15thDay
21212235%75%
2517
16th to endDay
221323336%70%
2333
September1st to 15thDay
1112212335%73%
2114
16th to endDay
5%415%4235%47%55%
1823
October1st to 15thDay
8%3244345%6%7%49%
1694
16th to endDay
10%6%25%435%5%7%8%38%
1603
November1st to 15thDay
14%8%45%6%45%6%6%7%30%
1583
16th to endDay
12%15%5%10%9%45%6%5%6%19%
1440
December1st to 15thDay
13%13%7%11%8%5%5%5%46%19%
1440
16th to endDay
19%13%6%11%8%35%5%45%16%
1536
January1st to 15thNight
19%14%5%8%7%45%446%20%
2506
16th to endNight
16%11%6%9%7%45%5%5%7%20%
2688
February1st to 15thNight
13%10%38%7%35%45%7%28%
2347
16th to endNight
10%8%38%6%35%45%7%33%
1895
March1st to 15thNight
11%9%37%6%35%5%6%7%33%
2160
16th to endNight
11%9%35%5%45%7%8%8%29%
2009
April1st to 15thNight
10%7%46%8%35%6%6%7%34%
1799
16th to endNight
6%7%37%5%24448%44%
1673
May1st to 15thNight
6%32432346%7%54%
1464
16th to endNight
5%5%36%7%346%7%8%39%
1496
June1st to 15thNight
8%4235%25%5%5%6%48%
1440
16th to endNight
7%3245%33446%54%
1440
July1st to 15thNight
21211245%7%69%
1440
16th to endNight
11111245%78%
1512
August1st to 15thNight
312212346%73%
1442
16th to endNight
112212345%73%
1866
September1st to 15thNight
1211212336%74%
1765
16th to endNight
5%31431345%7%57%
1806
October1st to 15thNight
9%4245%3345%7%49%
1933
16th to endNight
9%5%36%7%45%45%7%40%
2269
November1st to 15thNight
15%7%47%5%4445%6%34%
2275
16th to endNight
15%10%48%7%45%5%5%6%26%
2520
December1st to 15thNight
15%10%5%11%7%35%45%7%22%
2520
16th to endNight
18%12%49%6%445%47%21%
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
18%13%5%10%9%335%5%5%18%
1432
16th to endDay
16%14%9%11%6%45%445%16%
1536
February1st to 15thDay
14%11%48%7%46%445%25%
1504
16th to endDay
11%10%5%8%6%35%5%46%31%
1579
March1st to 15thDay
13%9%37%7%47%6%6%7%27%
1800
16th to endDay
13%8%47%7%36%6%6%6%28%
2210
April1st to 15thDay
7%6%36%6%36%6%7%7%36%
2149
16th to endDay
8%6%25%5%3446%7%44%
2286
May1st to 15thDay
6%4145%2445%8%52%
2484
16th to endDay
6%5%26%6%35%6%7%8%42%
2615
June1st to 15thDay
8%425%5%2445%7%48%
2520
16th to endDay
6%313423446%58%
2520
July1st to 15thDay
2212112235%74%
2520
16th to endDay
1111233479%
2657
August1st to 15thDay
22112335%75%
2517
16th to endDay
222322346%70%
2333
September1st to 15thDay
112212246%73%
2114
16th to endDay
6%414323446%55%
1823
October1st to 15thDay
8%4145%246%5%7%48%
1694
16th to endDay
11%7%24435%5%6%9%38%
1603
November1st to 15thDay
14%8%36%6%35%6%6%8%30%
1583
16th to endDay
13%15%5%10%8%35%6%5%6%20%
1440
December1st to 15thDay
14%13%8%10%7%45%5%45%19%
1440
16th to endDay
20%14%6%10%6%35%445%18%
1536
January1st to 15thNight
20%14%47%7%34445%21%
2506
16th to endNight
17%11%5%9%7%345%5%6%22%
2688
February1st to 15thNight
14%10%37%6%35%45%7%28%
2347
16th to endNight
12%8%47%7%3445%6%34%
1895
March1st to 15thNight
13%8%37%5%35%5%5%6%34%
2160
16th to endNight
12%8%36%6%36%7%7%8%29%
2013
April1st to 15thNight
10%7%46%6%46%5%5%7%35%
1799
16th to endNight
7%8%36%43435%8%43%
1673
May1st to 15thNight
6%31433346%8%53%
1464
16th to endNight
6%6%25%7%35%6%6%9%40%
1496
June1st to 15thNight
9%42443445%6%48%
1440
16th to endNight
7%3145%235%47%53%
1440
July1st to 15thNight
22121235%7%69%
1440
16th to endNight
11211235%78%
1512
August1st to 15thNight
311212346%73%
1442
16th to endNight
112213345%73%
1866
September1st to 15thNight
222112236%73%
1765
16th to endNight
6%41431326%8%56%
1806
October1st to 15thNight
9%425%43345%6%49%
1933
16th to endNight
10%5%26%6%35%5%5%7%40%
2269
November1st to 15thNight
16%9%36%6%35%45%6%33%
2275
16th to endNight
16%10%48%6%35%5%5%6%27%
2520
December1st to 15thNight
17%10%5%10%7%3446%6%24%
2520
16th to endNight
20%12%5%8%6%3445%6%22%
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
66%9%13%8%1
1432
16th to endDay
68%9%13%6%
1536
February1st to 15thDay
56%10%19%10%3
1504
16th to endDay
52%9%11%20%5%
1579
March1st to 15thDay
52%9%16%17%3
1800
16th to endDay
52%9%16%18%3
2210
April1st to 15thDay
41%8%17%23%8%
2149
16th to endDay
36%6%16%24%12%1
2286
May1st to 15thDay
30%5%10%30%20%2
2484
16th to endDay
36%8%15%26%10%2
2619
June1st to 15thDay
34%6%10%25%18%4
2520
16th to endDay
26%49%29%23%6%
2520
July1st to 15thDay
13%26%22%36%18%
2371
16th to endDay
9%26%17%37%25%
2490
August1st to 15thDay
11%37%22%38%17%
2500
16th to endDay
15%48%28%30%13%
2333
September1st to 15thDay
13%38%27%33%12%
2114
16th to endDay
28%5%14%27%18%5%
1823
October1st to 15thDay
32%6%17%27%14%1
1694
16th to endDay
40%9%18%23%7%
1603
November1st to 15thDay
48%11%16%18%31
1583
16th to endDay
61%9%14%11%2
1440
December1st to 15thDay
64%9%13%11%1
1440
16th to endDay
69%7%12%9%1
1536
January1st to 15thNight
65%8%13%10%2
2506
16th to endNight
61%10%15%11%2
2688
February1st to 15thNight
54%8%18%13%5%
2359
16th to endNight
50%7%12%22%5%
1895
March1st to 15thNight
47%7%15%22%7%
2160
16th to endNight
49%8%15%20%6%
2013
April1st to 15thNight
46%8%14%22%8%
1799
16th to endNight
38%5%14%23%14%3
1673
May1st to 15thNight
27%5%10%30%21%4
1465
16th to endNight
38%8%13%25%10%3
1496
June1st to 15thNight
32%6%10%24%21%3
1440
16th to endNight
30%39%24%22%8%
1440
July1st to 15thNight
14%36%19%31%25%
1360
16th to endNight
9%17%13%32%34%
1416
August1st to 15thNight
13%3416%38%23%
1434
16th to endNight
13%38%22%33%19%
1866
September1st to 15thNight
12%37%23%34%18%
1765
16th to endNight
25%312%26%20%10%
1806
October1st to 15thNight
34%5%12%25%20%1
1933
16th to endNight
40%8%14%22%11%1
2269
November1st to 15thNight
50%6%15%20%5%1
2275
16th to endNight
56%7%16%15%3
2520
December1st to 15thNight
60%8%15%13%1
2520
16th to endNight
62%7%16%11%2
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
28%110%20%30%10%
60
16th to endDay
32%310%34%15%3
64
February1st to 15thDay
20%12%19%25%17%4
162
16th to endDay
15%15%28%24%14%2
238
March1st to 15thDay
24%14%35%13%11%
270
16th to endDay
18%17%29%20%12%
288
April1st to 15thDay
10%17%32%22%12%4
269
16th to endDay
13%16%31%20%12%5%
270
May1st to 15thDay
12%13%27%23%18%5%
288
16th to endDay
7%8%20%24%27%11%
330
June1st to 15thDay
9%11%23%29%20%6%
315
16th to endDay
6%9%26%28%18%9%
315
July1st to 15thDay
2220%40%29%3
305
16th to endDay
1319%36%28%11%
327
August1st to 15thDay
2315%27%33%16%
315
16th to endDay
35%13%29%33%14%
332
September1st to 15thDay
3425%26%23%16%
300
16th to endDay
9%5%25%25%29%5%
255
October1st to 15thDay
14%7%23%27%22%3
255
16th to endDay
23%5%19%34%9%7%
115
November1st to 15thDay
24%10%19%31%13%1
89
16th to endDay
18%10%21%26%18%5%
60
December1st to 15thDay
30%13%30%21%31
60
16th to endDay
23%10%23%26%15%
64
January1st to 15thNight
26%10%16%26%16%3
720
16th to endNight
23%5%13%33%20%2
768
February1st to 15thNight
21%7%16%31%19%3
704
16th to endNight
16%11%20%30%18%1
632
March1st to 15thNight
18%7%25%31%14%2
720
16th to endNight
17%11%27%31%12%1
768
April1st to 15thNight
13%8%27%30%18%1
719
16th to endNight
11%9%25%28%21%3
593
May1st to 15thNight
8%8%23%28%27%3
385
16th to endNight
9%6%19%31%28%4
375
June1st to 15thNight
10%8%25%34%19%2
360
16th to endNight
10%423%34%23%3
360
July1st to 15thNight
5%220%32%35%2
340
16th to endNight
15%15%40%32%3
376
August1st to 15thNight
4111%37%39%6%
362
16th to endNight
3117%33%37%7%
720
September1st to 15thNight
3315%32%33%10%
706
16th to endNight
8%319%29%32%6%
656
October1st to 15thNight
12%5%20%34%25%2
660
16th to endNight
12%7%20%29%25%4
704
November1st to 15thNight
19%7%19%37%13%1
700
16th to endNight
21%9%15%30%19%3
720
December1st to 15thNight
21%7%15%37%15%2
720
16th to endNight
26%8%19%30%13%1
768
Page generated at 2017-09-13 04:39:18. Version ac04

Copyright 2017 A. Danko


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