Horseshoe Canyon
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Horseshoe Canyon clear sky chart from 2005-11-05 to 2017-10-16.

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
43%
15350
12%
47116
8%
15324
46%
15324
20%
32709

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
36%
895
9%
2685
6%
895
38%
895
14%
2059
January16th to endNight
40%
861
16%
2781
10%
861
48%
861
19%
1953
February1st to 15thNight
42%
697
11%
2392
11%
696
45%
696
16%
1695
February16th to endNight
46%
632
11%
2012
11%
632
49%
632
19%
1432
March1st to 15thNight
39%
720
12%
2094
7%
720
44%
720
19%
1519
March16th to endNight
37%
768
9%
2110
4%
767
41%
767
16%
1638
April1st to 15thNight
36%
599
9%
1686
4%
599
39%
599
17%
1271
April16th to endNight
41%
540
13%
1620
10%
540
44%
540
21%
1141
May1st to 15thNight
43%
446
11%
1401
9%
446
46%
446
23%
929
May16th to endNight
41%
374
5%
1309
2%
374
43%
374
16%
934
June1st to 15thNight
39%
360
0%
1260
0%
360
39%
360
15%
905
June16th to endNight
45%
360
0%
1260
0%
360
45%
360
19%
834
July1st to 15thNight
59%
340
0%
1190
0%
340
59%
340
22%
753
July16th to endNight
59%
376
8%
1239
7%
354
61%
354
29%
694
August1st to 15thNight
59%
423
9%
1490
11%
421
60%
421
26%
889
August16th to endNight
63%
573
19%
1719
16%
573
65%
573
38%
966
September1st to 15thNight
54%
624
17%
1794
12%
624
56%
624
32%
1118
September16th to endNight
54%
716
21%
1980
14%
716
59%
716
36%
1214
October1st to 15thNight
43%
720
15%
2118
9%
720
49%
720
23%
1444
October16th to endNight
43%
708
15%
2301
10%
708
50%
708
22%
1505
November1st to 15thNight
37%
858
17%
2433
11%
858
43%
858
23%
1676
November16th to endNight
34%
900
11%
2662
7%
900
37%
900
17%
1948
December1st to 15thNight
34%
900
9%
2700
6%
900
36%
900
13%
2099
December16th to endNight
38%
960
13%
2880
8%
960
43%
960
18%
2093

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
11%8%36%5%35%5%6%7%35%
48341
Night
9%9%47%6%35%5%5%8%34%
47264
TransparencyDay
45%8%16%20%7%
47991
Night
46%8%15%20%7%1
47118
SeeingDay
15%6%25%30%18%4
6163
Night
13%5%27%36%16%2
15364

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
8%12%48%7%5%5%5%7%7%27%
1253
16th to endDay
9%11%5%9%6%35%6%6%6%28%
1452
February1st to 15thDay
9%12%6%9%7%46%45%6%27%
1470
16th to endDay
5%14%7%11%8%36%6%5%6%23%
1461
March1st to 15thDay
8%9%5%10%9%46%5%5%7%26%
1866
16th to endDay
11%15%6%8%5%35%5%6%7%23%
2111
April1st to 15thDay
13%12%46%5%35%5%6%7%28%
2260
16th to endDay
16%9%35%6%35%5%5%7%31%
2340
May1st to 15thDay
13%6%26%5%35%5%6%7%37%
2548
16th to endDay
21%6%35%5%345%6%7%30%
2802
June1st to 15thDay
18%6%36%5%35%5%6%8%30%
2700
16th to endDay
15%4245%26%6%6%8%36%
2700
July1st to 15thDay
10%414435%5%6%9%43%
2700
16th to endDay
8%3133345%6%10%48%
2846
August1st to 15thDay
12%5%244245%5%9%44%
2460
16th to endDay
9%31432446%7%50%
2483
September1st to 15thDay
13%6%25%413446%47%
2163
16th to endDay
9%5%2433445%8%47%
1980
October1st to 15thDay
14%8%36%6%3345%7%37%
1841
16th to endDay
7%10%35%5%35%5%6%7%38%
1591
November1st to 15thDay
9%14%5%7%6%35%45%6%32%
1414
16th to endDay
8%12%410%7%3447%7%29%
1296
December1st to 15thDay
9%15%6%9%9%5%6%5%4422%
1260
16th to endDay
411%6%13%7%46%7%5%7%25%
1344
January1st to 15thNight
7%13%5%9%7%47%7%5%8%22%
2685
16th to endNight
6%13%5%8%5%35%5%6%8%31%
2781
February1st to 15thNight
7%11%6%9%7%45%45%8%29%
2381
16th to endNight
6%10%6%9%6%36%6%6%7%30%
2012
March1st to 15thNight
5%9%5%8%8%47%5%6%9%30%
2094
16th to endNight
9%12%5%8%7%46%6%6%7%24%
2109
April1st to 15thNight
12%10%48%7%46%45%8%27%
1686
16th to endNight
11%9%46%5%35%46%7%33%
1620
May1st to 15thNight
12%7%37%5%25%5%5%7%37%
1400
16th to endNight
20%6%15%5%35%5%5%6%32%
1309
June1st to 15thNight
15%8%36%5%46%5%6%8%29%
1260
16th to endNight
11%6%27%6%35%47%8%36%
1260
July1st to 15thNight
8%3246%46%6%8%8%40%
1260
16th to endNight
6%2245%345%5%8%51%
1323
August1st to 15thNight
10%325%5%2446%9%45%
1497
16th to endNight
8%41342347%9%51%
1719
September1st to 15thNight
14%424413446%49%
1794
16th to endNight
9%5%2342446%8%49%
1980
October1st to 15thNight
11%7%36%5%35%45%8%36%
2118
16th to endNight
8%8%46%5%25%5%6%9%37%
2301
November1st to 15thNight
8%9%46%6%35%46%7%37%
2433
16th to endNight
8%10%410%8%36%5%5%7%29%
2662
December1st to 15thNight
7%14%5%11%8%5%5%5%48%23%
2700
16th to endNight
5%11%5%9%8%46%5%5%8%28%
2880

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
53%8%14%17%41
1253
16th to endDay
50%8%15%15%7%2
1452
February1st to 15thDay
55%7%15%15%6%
1470
16th to endDay
59%6%13%14%5%
1461
March1st to 15thDay
54%9%16%13%5%
1866
16th to endDay
55%9%14%15%3
2112
April1st to 15thDay
52%9%15%15%7%
2260
16th to endDay
50%8%13%18%7%1
2340
May1st to 15thDay
44%8%15%21%10%
2548
16th to endDay
52%8%15%17%5%
2807
June1st to 15thDay
50%9%15%18%5%1
2700
16th to endDay
41%10%19%22%5%
2700
July1st to 15thDay
36%9%21%25%6%
2541
16th to endDay
29%9%22%28%9%
2667
August1st to 15thDay
36%9%23%22%7%
2442
16th to endDay
30%7%21%29%10%1
2483
September1st to 15thDay
37%6%14%24%13%3
2163
16th to endDay
33%7%16%27%10%3
1980
October1st to 15thDay
46%6%16%22%8%
1841
16th to endDay
42%8%15%23%9%
1591
November1st to 15thDay
52%7%14%17%6%1
1414
16th to endDay
52%8%14%15%7%
1296
December1st to 15thDay
62%7%11%14%3
1260
16th to endDay
54%9%15%15%5%
1344
January1st to 15thNight
55%9%14%14%41
2685
16th to endNight
48%7%13%19%8%2
2781
February1st to 15thNight
51%6%13%18%8%
2392
16th to endNight
49%7%15%15%10%
2012
March1st to 15thNight
47%9%19%17%5%
2094
16th to endNight
55%8%12%18%31
2112
April1st to 15thNight
54%6%15%15%6%
1686
16th to endNight
46%8%12%23%6%2
1620
May1st to 15thNight
43%6%12%23%11%1
1401
16th to endNight
50%8%13%17%7%1
1309
June1st to 15thNight
51%9%12%18%7%
1260
16th to endNight
42%9%19%20%6%
1260
July1st to 15thNight
37%11%21%22%6%
1190
16th to endNight
29%9%22%27%10%1
1239
August1st to 15thNight
34%9%23%23%8%
1490
16th to endNight
27%6%18%31%12%3
1719
September1st to 15thNight
35%6%13%23%14%6%
1794
16th to endNight
31%7%16%27%14%3
1980
October1st to 15thNight
44%7%15%21%9%1
2118
16th to endNight
41%9%17%24%6%
2301
November1st to 15thNight
45%6%15%22%8%1
2433
16th to endNight
51%7%16%15%6%1
2662
December1st to 15thNight
59%7%14%15%2
2700
16th to endNight
51%7%15%20%5%
2880

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
15%116%31%18%16%
60
16th to endDay
6%428%21%29%9%
64
February1st to 15thDay
21%417%34%17%4
73
16th to endDay
12%6%25%35%18%
120
March1st to 15thDay
13%5%37%35%7%1
270
16th to endDay
11%7%37%27%14%1
288
April1st to 15thDay
15%15%28%27%10%1
269
16th to endDay
21%7%24%29%13%2
270
May1st to 15thDay
13%9%25%28%19%3
414
16th to endDay
22%5%17%29%20%4
517
June1st to 15thDay
18%7%26%30%14%3
495
16th to endDay
16%426%29%16%5%
495
July1st to 15thDay
9%220%34%24%8%
475
16th to endDay
9%425%32%22%6%
515
August1st to 15thDay
12%217%34%25%7%
318
16th to endDay
8%6%23%31%24%6%
332
September1st to 15thDay
21%6%22%25%18%5%
315
16th to endDay
10%9%28%26%20%4
315
October1st to 15thDay
22%425%28%16%2
179
16th to endDay
16%423%34%18%4
99
November1st to 15thDay
25%8%22%34%8%
90
16th to endDay
7%10%31%25%9%15%
66
December1st to 15thDay
10%141%25%18%3
60
16th to endDay
12%329%18%29%6%
64
January1st to 15thNight
14%7%29%32%14%2
900
16th to endNight
12%5%29%37%12%2
861
February1st to 15thNight
10%7%23%34%20%2
704
16th to endNight
11%324%39%18%3
632
March1st to 15thNight
10%433%35%13%2
720
16th to endNight
13%5%28%37%13%1
768
April1st to 15thNight
17%6%28%31%14%1
599
16th to endNight
17%5%27%36%12%1
540
May1st to 15thNight
15%8%24%35%15%
447
16th to endNight
24%323%26%20%
375
June1st to 15thNight
19%5%26%31%14%2
360
16th to endNight
12%5%26%35%19%1
360
July1st to 15thNight
9%118%45%23%1
340
16th to endNight
7%221%47%20%1
376
August1st to 15thNight
11%20%36%28%2
423
16th to endNight
9%319%43%23%1
573
September1st to 15thNight
16%419%37%20%1
624
16th to endNight
10%5%24%39%16%3
716
October1st to 15thNight
15%328%34%16%2
720
16th to endNight
12%429%39%12%1
708
November1st to 15thNight
12%7%34%32%10%2
858
16th to endNight
11%6%33%33%12%1
900
December1st to 15thNight
12%6%29%33%16%2
900
16th to endNight
10%429%36%15%3
960
Page generated at 2017-10-17 14:35:29. Version ac04

Copyright 2017 A. Danko


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