Takhini Hot Springs
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Takhini Hot Springs clear sky chart from 2005-11-05 to 2018-01-20.

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
41%
14585
5%
48419
5%
14553
42%
14553
12%
37470

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%
912
4%
3386
4%
908
38%
908
8%
2836
January16th to endNight
33%
825
8%
3162
8%
825
37%
825
8%
2531
February1st to 15thNight
38%
734
6%
2585
4%
730
42%
730
12%
1991
February16th to endNight
47%
659
9%
2127
8%
659
47%
659
14%
1632
March1st to 15thNight
43%
724
12%
2187
11%
724
45%
724
17%
1622
March16th to endNight
48%
585
9%
2009
10%
585
48%
585
15%
1459
April1st to 15thNight
54%
539
6%
1659
4%
539
54%
539
20%
1163
April16th to endNight
55%
540
2%
1440
2%
540
55%
540
23%
1021
May1st to 15thNight
50%
362
0%
1103
0%
362
50%
362
22%
733
May16th to endNight
60%
323
0%
999
0%
323
60%
323
24%
638
June1st to 15thNight
52%
180
0%
720
0%
180
52%
180
16%
479
June16th to endNight
51%
180
0%
720
0%
180
51%
180
14%
500
July1st to 15thNight
52%
170
0%
711
0%
170
52%
170
12%
489
July16th to endNight
49%
317
0%
1003
0%
295
48%
295
18%
700
August1st to 15thNight
50%
449
0%
1191
0%
447
50%
447
23%
836
August16th to endNight
37%
573
1%
1528
0%
573
38%
573
13%
1229
September1st to 15thNight
42%
540
6%
1768
5%
540
43%
540
14%
1321
September16th to endNight
38%
643
10%
1964
9%
643
40%
643
15%
1457
October1st to 15thNight
37%
720
8%
2215
7%
720
38%
720
13%
1700
October16th to endNight
38%
804
4%
2643
2%
804
40%
804
11%
2088
November1st to 15thNight
36%
805
3%
2915
3%
805
37%
805
7%
2435
November16th to endNight
33%
893
5%
3188
4%
893
35%
893
8%
2636
December1st to 15thNight
34%
1020
4%
3452
3%
1020
35%
1020
7%
2928
December16th to endNight
39%
1088
8%
3744
7%
1088
41%
1088
9%
3046

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
9%10%5%10%9%47%6%6%7%21%
49192
Night
6%11%5%10%9%5%7%6%6%7%21%
48521
TransparencyDay
57%9%16%13%3
48798
Night
56%11%15%14%3
48420
SeeingDay
14%10%23%28%18%4
7910
Night
10%5%22%34%22%4
14588

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
311%8%15%16%8%6%5%5%6%11%
895
16th to endDay
412%7%12%12%5%10%6%8%8%11%
1166
February1st to 15thDay
111%7%10%9%7%8%7%7%9%17%
1278
16th to endDay
311%411%11%6%5%8%7%7%22%
1347
March1st to 15thDay
19%6%12%10%5%8%7%8%7%21%
1773
16th to endDay
210%6%10%10%5%7%6%7%8%25%
2215
April1st to 15thDay
411%49%8%5%6%6%7%10%23%
2286
16th to endDay
411%7%12%8%47%5%5%7%24%
2520
May1st to 15thDay
9%12%5%10%8%46%5%5%6%23%
2845
16th to endDay
8%8%48%8%46%6%6%8%29%
3112
June1st to 15thDay
13%9%48%8%46%5%5%8%24%
3240
16th to endDay
12%9%5%10%10%47%5%6%8%20%
3240
July1st to 15thDay
13%8%5%8%8%48%6%7%7%20%
3206
16th to endDay
14%8%48%7%47%6%6%7%22%
3095
August1st to 15thDay
11%8%47%6%46%6%6%9%28%
2762
16th to endDay
20%12%49%7%46%6%5%6%17%
2674
September1st to 15thDay
15%12%5%9%7%45%5%5%6%22%
2189
16th to endDay
13%12%49%8%46%5%5%7%22%
1996
October1st to 15thDay
10%13%411%8%46%5%5%6%23%
1745
16th to endDay
5%12%6%10%8%5%7%7%6%8%21%
1578
November1st to 15thDay
412%8%14%12%47%7%5%5%15%
1272
16th to endDay
314%7%14%13%7%7%7%8%6%10%
1088
December1st to 15thDay
415%5%13%12%5%8%7%6%10%9%
838
16th to endDay
312%5%11%14%6%10%7%7%8%12%
832
January1st to 15thNight
314%7%13%12%5%9%5%5%7%15%
3386
16th to endNight
411%7%12%10%5%9%8%7%8%13%
3162
February1st to 15thNight
311%5%11%10%5%9%7%7%8%18%
2573
16th to endNight
39%6%10%10%5%8%7%6%8%24%
2127
March1st to 15thNight
211%5%11%7%5%7%6%5%7%28%
2187
16th to endNight
29%7%12%9%47%6%7%6%27%
2004
April1st to 15thNight
28%5%11%7%5%7%6%6%8%30%
1659
16th to endNight
47%47%7%37%6%8%8%32%
1440
May1st to 15thNight
7%6%36%6%36%6%8%9%34%
1103
16th to endNight
5%5%47%5%46%6%7%7%39%
999
June1st to 15thNight
10%6%37%8%36%6%6%8%31%
720
16th to endNight
9%7%27%7%47%8%8%8%26%
720
July1st to 15thNight
10%5%45%8%5%10%6%8%7%27%
753
16th to endNight
11%6%36%5%448%7%11%29%
1074
August1st to 15thNight
9%416%7%46%7%7%11%34%
1197
16th to endNight
17%10%39%45%7%5%6%6%22%
1528
September1st to 15thNight
13%7%47%8%47%5%6%6%28%
1768
16th to endNight
11%12%49%7%45%5%5%7%26%
1964
October1st to 15thNight
10%15%48%6%35%5%5%6%27%
2215
16th to endNight
7%14%6%10%9%47%46%6%22%
2643
November1st to 15thNight
413%8%13%12%48%7%6%7%13%
2915
16th to endNight
313%7%13%13%6%7%7%7%6%13%
3188
December1st to 15thNight
5%14%6%11%10%6%8%6%6%8%13%
3452
16th to endNight
312%6%10%12%7%9%7%7%8%14%
3744

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%9%8%7%2
895
16th to endDay
62%11%14%9%2
1166
February1st to 15thDay
56%12%11%13%5%
1278
16th to endDay
54%12%14%12%6%
1347
March1st to 15thDay
54%8%13%17%41
1773
16th to endDay
52%10%16%12%7%
2215
April1st to 15thDay
52%11%19%13%3
2286
16th to endDay
57%8%15%15%3
2520
May1st to 15thDay
58%9%12%16%4
2845
16th to endDay
48%8%17%20%5%
3116
June1st to 15thDay
55%7%16%15%4
3240
16th to endDay
59%8%16%13%1
3240
July1st to 15thDay
56%11%18%12%2
3019
16th to endDay
55%10%21%11%
2903
August1st to 15thDay
49%10%23%14%2
2743
16th to endDay
63%10%16%9%
2674
September1st to 15thDay
58%10%17%12%1
2189
16th to endDay
59%9%16%12%1
1996
October1st to 15thDay
58%9%15%13%2
1745
16th to endDay
57%13%20%7%
1578
November1st to 15thDay
66%10%13%8%1
1272
16th to endDay
67%10%11%7%2
1088
December1st to 15thDay
66%12%12%7%1
838
16th to endDay
62%10%10%11%3
832
January1st to 15thNight
65%10%11%8%3
3386
16th to endNight
61%11%11%13%2
3162
February1st to 15thNight
56%10%13%16%2
2585
16th to endNight
51%13%13%12%7%
2127
March1st to 15thNight
51%9%11%19%6%1
2187
16th to endNight
52%9%14%13%9%
2009
April1st to 15thNight
46%8%21%18%4
1659
16th to endNight
41%11%18%24%3
1440
May1st to 15thNight
39%10%20%22%6%
1104
16th to endNight
38%9%20%23%8%
999
June1st to 15thNight
46%8%18%22%4
720
16th to endNight
47%11%22%15%2
720
July1st to 15thNight
47%12%19%18%2
711
16th to endNight
41%15%22%18%1
1003
August1st to 15thNight
38%15%24%17%4
1191
16th to endNight
58%10%19%10%
1528
September1st to 15thNight
51%12%18%17%1
1768
16th to endNight
54%7%18%17%2
1964
October1st to 15thNight
55%10%16%14%2
2215
16th to endNight
57%12%18%9%1
2643
November1st to 15thNight
65%11%13%8%
2915
16th to endNight
65%10%11%11%1
3188
December1st to 15thNight
65%12%11%8%1
3452
16th to endNight
62%10%11%11%4
3744

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
13%411%28%31%11%
45
16th to endDay
5%213%44%23%9%
72
February1st to 15thDay
5%6%26%35%19%6%
236
16th to endDay
8%5%23%34%18%9%
211
March1st to 15thDay
5%12%31%27%17%6%
240
16th to endDay
6%9%22%32%24%5%
276
April1st to 15thDay
8%16%28%23%17%5%
347
16th to endDay
11%18%26%32%9%1
450
May1st to 15thDay
17%18%26%25%9%2
468
16th to endDay
12%11%25%28%16%6%
590
June1st to 15thDay
16%8%24%28%19%2
675
16th to endDay
13%7%17%33%23%3
675
July1st to 15thDay
16%7%18%29%23%4
613
16th to endDay
17%9%21%26%20%3
515
August1st to 15thDay
13%9%22%27%20%6%
494
16th to endDay
25%12%27%23%9%1
523
September1st to 15thDay
26%13%22%17%14%4
338
16th to endDay
17%15%24%19%16%5%
301
October1st to 15thDay
16%15%27%24%10%5%
270
16th to endDay
13%9%22%28%20%6%
285
November1st to 15thDay
15%5%14%31%28%4
90
16th to endDay
6%118%33%24%15%
90
December1st to 15thDay
13%39%27%18%
58
16th to endDay
426%43%18%25%
48
January1st to 15thNight
7%325%39%20%3
913
16th to endNight
9%6%27%38%16%2
825
February1st to 15thNight
5%429%41%16%2
734
16th to endNight
6%423%39%20%5%
659
March1st to 15thNight
5%7%27%32%24%2
724
16th to endNight
35%15%28%38%7%
585
April1st to 15thNight
35%19%33%32%5%
539
16th to endNight
6%5%19%32%31%4
540
May1st to 15thNight
8%9%21%31%23%4
363
16th to endNight
7%416%37%33%1
324
June1st to 15thNight
11%5%20%39%20%2
180
16th to endNight
11%320%35%27%1
180
July1st to 15thNight
13%417%26%35%2
170
16th to endNight
12%421%31%24%5%
317
August1st to 15thNight
11%322%30%25%6%
449
16th to endNight
23%423%23%22%3
573
September1st to 15thNight
16%7%22%29%19%3
540
16th to endNight
17%8%23%27%19%2
643
October1st to 15thNight
19%8%22%30%17%2
720
16th to endNight
13%6%24%32%21%2
804
November1st to 15thNight
8%422%39%20%5%
805
16th to endNight
9%6%21%34%23%4
893
December1st to 15thNight
10%7%23%35%17%5%
1020
16th to endNight
8%422%33%22%7%
1088
Page generated at 2018-01-21 09:19:33. Version ac04

Copyright 2018 A. Danko


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