Rathdrum
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rathdrum clear sky chart from 2005-11-05 to 2017-09-24.

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
48%
14970
13%
46918
12%
14939
50%
14939
20%
32238

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
26%
719
6%
2506
5%
716
27%
716
7%
2088
January16th to endNight
37%
768
7%
2688
7%
768
38%
768
11%
2077
February1st to 15thNight
35%
702
6%
2399
6%
698
38%
698
12%
1845
February16th to endNight
39%
632
13%
1895
12%
632
42%
632
15%
1424
March1st to 15thNight
37%
720
6%
2160
6%
720
39%
720
14%
1675
March16th to endNight
38%
768
8%
2025
5%
768
40%
768
15%
1615
April1st to 15thNight
47%
719
12%
1799
7%
719
49%
719
22%
1306
April16th to endNight
50%
544
15%
1624
13%
544
51%
544
21%
1111
May1st to 15thNight
59%
404
18%
1485
23%
404
62%
404
28%
830
May16th to endNight
57%
374
12%
1451
17%
374
60%
374
20%
906
June1st to 15thNight
56%
360
9%
1260
8%
360
58%
360
25%
761
June16th to endNight
61%
360
13%
1260
14%
360
62%
360
28%
715
July1st to 15thNight
80%
340
17%
1305
22%
340
84%
340
53%
513
July16th to endNight
83%
376
26%
1416
42%
354
85%
354
61%
491
August1st to 15thNight
84%
381
29%
1453
39%
379
87%
379
54%
559
August16th to endNight
77%
651
32%
1797
24%
651
80%
651
56%
901
September1st to 15thNight
75%
720
30%
1818
18%
720
77%
720
57%
952
September16th to endNight
63%
692
25%
1914
20%
692
65%
692
36%
1163
October1st to 15thNight
55%
660
19%
1919
17%
660
57%
660
29%
1203
October16th to endNight
49%
704
14%
2288
15%
704
51%
704
18%
1589
November1st to 15thNight
36%
700
9%
2275
9%
700
38%
700
12%
1770
November16th to endNight
37%
819
5%
2604
5%
819
38%
819
12%
2042
December1st to 15thNight
33%
900
6%
2700
4%
900
35%
900
10%
2228
December16th to endNight
24%
957
4%
2877
2%
957
26%
957
7%
2474

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
15%9%35%424446%39%
48016
Night
16%9%35%5%24446%37%
47087
Cloud CoverDay
15%9%35%424446%38%
48017
Night
16%10%35%424446%36%
47090
TransparencyDay
46%5%12%20%11%2
47688
Night
48%5%12%18%11%3
46918
SeeingDay
18%10%23%25%17%4
5753
Night
22%5%14%31%22%3
14975

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
28%16%46%5%24436%16%
1432
16th to endDay
23%19%46%5%335%5%419%
1536
February1st to 15thDay
22%17%47%5%245%45%20%
1461
16th to endDay
20%18%6%7%6%23335%22%
1579
March1st to 15thDay
25%17%47%5%4433419%
1800
16th to endDay
24%15%48%6%35%435%18%
2197
April1st to 15thDay
19%10%47%7%36%45%6%23%
2149
16th to endDay
17%8%36%6%36%45%6%32%
2334
May1st to 15thDay
9%6%26%5%35%5%5%7%42%
2463
16th to endDay
14%6%37%5%35%5%6%9%32%
2657
June1st to 15thDay
18%425%5%3445%6%38%
2700
16th to endDay
13%414435%5%46%46%
2700
July1st to 15thDay
5%213223445%65%
2573
16th to endDay
111213345%74%
2657
August1st to 15thDay
3212213346%68%
2499
16th to endDay
431222335%6%63%
2402
September1st to 15thDay
4312323346%65%
2142
16th to endDay
11%5%2433445%7%47%
1904
October1st to 15thDay
18%8%25%42333442%
1708
16th to endDay
23%8%36%5%23345%32%
1584
November1st to 15thDay
29%12%36%424335%24%
1584
16th to endDay
22%17%5%10%7%1333419%
1338
December1st to 15thDay
22%16%7%7%5%24446%18%
1260
16th to endDay
26%21%5%9%5%2323315%
1357
January1st to 15thNight
28%15%5%7%5%3333318%
2506
16th to endNight
23%14%47%5%23435%24%
2688
February1st to 15thNight
22%16%36%5%23245%27%
2388
16th to endNight
17%14%36%5%33346%30%
1895
March1st to 15thNight
20%11%36%6%34446%26%
2160
16th to endNight
21%10%35%5%35%5%5%6%25%
2022
April1st to 15thNight
12%9%46%5%45%5%6%5%34%
1799
16th to endNight
12%8%26%5%45%45%6%38%
1624
May1st to 15thNight
8%4245%25%5%6%8%46%
1484
16th to endNight
11%5%36%5%26%5%6%9%36%
1451
June1st to 15thNight
12%324426%5%5%7%44%
1260
16th to endNight
11%42442446%7%47%
1260
July1st to 15thNight
312312246%71%
1385
16th to endNight
112212336%75%
1512
August1st to 15thNight
21221235%6%70%
1461
16th to endNight
2113323346%68%
1797
September1st to 15thNight
4212312247%67%
1818
16th to endNight
10%415%5%2435%7%49%
1914
October1st to 15thNight
15%425%433346%46%
1919
16th to endNight
19%7%35%5%23446%35%
2288
November1st to 15thNight
24%12%45%43345%6%25%
2275
16th to endNight
26%13%36%5%34445%24%
2604
December1st to 15thNight
21%16%5%7%5%24445%22%
2700
16th to endNight
26%19%6%8%5%2334417%
2877

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
28%18%46%5%3443417%
1432
16th to endDay
23%19%46%424445%19%
1536
February1st to 15thDay
22%18%47%5%34445%20%
1461
16th to endDay
20%18%6%8%6%2333322%
1579
March1st to 15thDay
24%19%47%6%43335%18%
1800
16th to endDay
24%16%49%6%3443418%
2198
April1st to 15thDay
18%11%48%6%45%5%46%22%
2149
16th to endDay
16%9%36%5%35%45%6%31%
2334
May1st to 15thDay
9%6%36%5%35%6%5%7%41%
2463
16th to endDay
14%6%36%6%35%5%5%8%32%
2657
June1st to 15thDay
18%5%345%35%45%7%37%
2700
16th to endDay
13%4235%25%5%5%7%45%
2700
July1st to 15thDay
5%212323445%65%
2573
16th to endDay
111213345%74%
2657
August1st to 15thDay
3212313346%67%
2499
16th to endDay
431231445%7%62%
2402
September1st to 15thDay
4212313346%65%
2142
16th to endDay
12%5%2443345%7%45%
1904
October1st to 15thDay
17%8%25%42333442%
1708
16th to endDay
23%9%35%5%23345%32%
1584
November1st to 15thDay
28%14%45%424345%23%
1584
16th to endDay
22%18%5%9%5%2423419%
1338
December1st to 15thDay
22%16%7%7%5%25%44417%
1260
16th to endDay
26%20%6%8%7%2322315%
1357
January1st to 15thNight
28%16%5%7%5%2333417%
2506
16th to endNight
23%15%5%5%424346%23%
2688
February1st to 15thNight
22%15%47%424235%27%
2388
16th to endNight
17%14%36%5%2435%5%29%
1895
March1st to 15thNight
20%11%36%6%35%445%26%
2160
16th to endNight
20%11%45%5%36%6%5%6%24%
2025
April1st to 15thNight
12%9%36%6%35%5%6%7%33%
1799
16th to endNight
12%8%35%5%36%445%38%
1624
May1st to 15thNight
8%5%245%25%5%6%9%45%
1484
16th to endNight
11%5%36%6%35%5%7%9%35%
1451
June1st to 15thNight
11%4245%25%6%5%7%43%
1260
16th to endNight
10%5%25%4245%6%6%46%
1260
July1st to 15thNight
312212346%71%
1385
16th to endNight
1111211335%76%
1512
August1st to 15thNight
21221235%6%70%
1461
16th to endNight
1213323345%68%
1797
September1st to 15thNight
3212313247%66%
1818
16th to endNight
10%4145%2435%7%49%
1914
October1st to 15thNight
14%5%2442335%7%45%
1919
16th to endNight
19%8%26%5%34446%35%
2288
November1st to 15thNight
24%13%35%5%34446%24%
2275
16th to endNight
26%13%36%434345%23%
2604
December1st to 15thNight
21%17%5%8%5%25%345%20%
2700
16th to endNight
25%20%6%7%5%2433416%
2877

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
71%6%11%7%3
1432
16th to endDay
65%5%15%9%3
1536
February1st to 15thDay
66%7%12%9%3
1461
16th to endDay
67%5%8%14%3
1579
March1st to 15thDay
70%5%13%9%1
1800
16th to endDay
69%5%12%9%1
2198
April1st to 15thDay
61%5%15%14%3
2149
16th to endDay
53%7%15%17%4
2334
May1st to 15thDay
41%5%15%26%10%
2463
16th to endDay
48%6%17%22%4
2661
June1st to 15thDay
45%6%11%23%10%2
2700
16th to endDay
37%6%13%28%12%1
2700
July1st to 15thDay
21%39%30%23%10%
2424
16th to endDay
12%49%24%38%11%
2490
August1st to 15thDay
17%38%31%31%8%
2482
16th to endDay
20%410%30%27%6%
2402
September1st to 15thDay
20%411%30%26%7%
2142
16th to endDay
37%5%17%22%13%3
1904
October1st to 15thDay
45%413%26%9%
1708
16th to endDay
54%5%15%20%3
1584
November1st to 15thDay
63%6%12%12%31
1584
16th to endDay
68%6%11%9%3
1338
December1st to 15thDay
71%6%9%11%1
1260
16th to endDay
75%5%9%8%1
1357
January1st to 15thNight
70%5%10%9%2
2506
16th to endNight
61%6%15%12%21
2688
February1st to 15thNight
61%5%15%12%4
2399
16th to endNight
56%6%12%16%7%
1895
March1st to 15thNight
59%6%15%14%4
2160
16th to endNight
57%9%12%15%5%
2025
April1st to 15thNight
48%6%15%21%7%
1799
16th to endNight
47%5%12%23%10%
1624
May1st to 15thNight
34%5%14%30%13%1
1485
16th to endNight
42%7%15%25%9%
1451
June1st to 15thNight
38%6%10%24%16%3
1260
16th to endNight
36%49%27%18%4
1260
July1st to 15thNight
15%25%26%33%17%
1305
16th to endNight
11%16%19%36%24%
1416
August1st to 15thNight
13%38%21%39%13%
1453
16th to endNight
17%37%27%31%12%
1797
September1st to 15thNight
18%37%28%30%11%
1818
16th to endNight
34%313%23%17%6%
1914
October1st to 15thNight
39%312%29%13%1
1919
16th to endNight
49%6%13%22%7%
2288
November1st to 15thNight
60%7%12%14%32
2275
16th to endNight
63%5%15%11%3
2604
December1st to 15thNight
66%7%12%12%1
2700
16th to endNight
72%6%10%9%1
2877

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
21%118%30%21%6%
60
16th to endDay
45%417%18%9%4
64
February1st to 15thDay
31%17%13%21%15%
104
16th to endDay
36%13%19%19%9%2
238
March1st to 15thDay
38%19%21%15%4
270
16th to endDay
32%16%23%21%5%
288
April1st to 15thDay
21%17%28%19%8%4
269
16th to endDay
22%15%23%21%12%2
270
May1st to 15thDay
13%15%28%23%16%2
288
16th to endDay
13%8%19%27%22%8%
372
June1st to 15thDay
16%6%26%26%20%4
495
16th to endDay
14%8%22%27%21%6%
495
July1st to 15thDay
6%5%24%30%28%3
358
16th to endDay
110%29%34%17%7%
327
August1st to 15thDay
6%421%33%25%9%
315
16th to endDay
38%25%30%22%9%
332
September1st to 15thDay
7%9%28%24%21%7%
315
16th to endDay
13%14%23%22%22%2
288
October1st to 15thDay
21%11%23%26%15%1
233
16th to endDay
45%215%22%8%5%
96
November1st to 15thDay
40%6%8%31%13%
90
16th to endDay
32%324%24%12%3
62
December1st to 15thDay
43%11%23%15%5%1
60
16th to endDay
42%7%18%23%7%
64
January1st to 15thNight
39%7%13%23%13%1
720
16th to endNight
30%6%11%29%19%1
768
February1st to 15thNight
34%6%13%28%13%2
704
16th to endNight
25%6%17%27%20%3
632
March1st to 15thNight
26%8%16%32%14%1
720
16th to endNight
27%6%19%30%14%1
768
April1st to 15thNight
16%8%18%33%20%2
719
16th to endNight
18%7%17%33%20%2
544
May1st to 15thNight
12%417%31%28%6%
405
16th to endNight
14%413%29%30%7%
375
June1st to 15thNight
13%318%33%25%5%
360
16th to endNight
13%312%36%30%4
360
July1st to 15thNight
4110%36%44%3
340
16th to endNight
118%39%44%3
376
August1st to 15thNight
316%33%46%9%
381
16th to endNight
339%34%40%9%
651
September1st to 15thNight
6%211%30%38%10%
720
16th to endNight
14%113%33%29%7%
692
October1st to 15thNight
19%312%35%26%2
660
16th to endNight
24%314%29%24%3
704
November1st to 15thNight
33%7%14%31%12%
700
16th to endNight
35%6%11%25%18%2
819
December1st to 15thNight
31%7%15%30%14%
900
16th to endNight
38%7%15%29%8%
957
Page generated at 2017-09-25 06:02:24. Version ac04

Copyright 2017 A. Danko


Rathdrum Clear Sky Chart | Charts Home