Tulelake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tulelake 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
60%
15426
22%
48510
20%
15398
63%
15398
32%
28480

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
53%
776
13%
2716
14%
776
55%
776
21%
1779
January16th to endNight
52%
788
20%
2610
21%
788
54%
788
23%
1680
February1st to 15thNight
50%
696
13%
2288
13%
696
52%
696
21%
1553
February16th to endNight
51%
632
17%
1930
16%
632
55%
632
23%
1284
March1st to 15thNight
42%
720
11%
2067
9%
720
45%
720
21%
1473
March16th to endNight
42%
768
14%
2058
10%
768
45%
768
23%
1455
April1st to 15thNight
44%
719
15%
1799
8%
719
46%
719
25%
1273
April16th to endNight
54%
720
19%
1800
10%
720
57%
720
38%
1126
May1st to 15thNight
59%
414
21%
1494
18%
414
64%
414
35%
776
May16th to endNight
57%
375
17%
1496
19%
374
63%
374
26%
820
June1st to 15thNight
62%
360
17%
1440
22%
360
68%
360
29%
749
June16th to endNight
75%
360
28%
1440
41%
360
81%
360
52%
559
July1st to 15thNight
85%
340
28%
1360
40%
340
89%
340
58%
495
July16th to endNight
89%
406
37%
1444
45%
382
92%
382
68%
507
August1st to 15thNight
90%
538
34%
1611
30%
535
92%
535
63%
713
August16th to endNight
85%
738
43%
1884
28%
738
86%
738
76%
854
September1st to 15thNight
85%
720
41%
1800
26%
720
88%
720
75%
836
September16th to endNight
76%
716
37%
1954
31%
716
79%
716
55%
981
October1st to 15thNight
67%
720
26%
2160
26%
720
73%
720
47%
1108
October16th to endNight
65%
768
26%
2319
28%
768
67%
768
37%
1317
November1st to 15thNight
55%
760
17%
2470
17%
760
58%
760
24%
1608
November16th to endNight
52%
780
13%
2728
13%
780
55%
780
22%
1754
December1st to 15thNight
53%
780
16%
2730
17%
780
56%
780
22%
1756
December16th to endNight
42%
832
16%
2912
16%
832
44%
832
17%
2024

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%5%24424446%51%
49036
Night
8%6%24424446%50%
48685
TransparencyDay
32%5%11%20%19%11%
48710
Night
33%5%13%21%17%8%
48511
SeeingDay
12%10%21%25%19%10%
6077
Night
10%5%17%36%26%3
15439

By Month

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%9%37%5%36%5%6%10%29%
1552
16th to endDay
15%9%26%4245%47%36%
1717
February1st to 15thDay
11%9%36%6%26%5%6%8%33%
1576
16th to endDay
8%10%47%7%45%5%5%7%32%
1544
March1st to 15thDay
11%12%5%6%6%45%447%30%
1891
16th to endDay
10%10%47%6%345%49%32%
2166
April1st to 15thDay
11%8%48%7%45%45%5%32%
2149
16th to endDay
10%5%25%5%24347%47%
2160
May1st to 15thDay
6%5%1442435%7%53%
2454
16th to endDay
10%7%26%423446%46%
2615
June1st to 15thDay
7%42442345%6%52%
2520
16th to endDay
412212236%71%
2520
July1st to 15thDay
121212345%73%
2520
16th to endDay
11111234477%
2624
August1st to 15thDay
11121345%5%71%
2340
16th to endDay
2111113482%
2318
September1st to 15thDay
11211123480%
2160
16th to endDay
4213313346%64%
2004
October1st to 15thDay
8%413313446%58%
1800
16th to endDay
10%6%14424447%48%
1903
November1st to 15thDay
13%7%36%5%35%448%36%
1719
16th to endDay
11%9%37%6%345%5%7%34%
1560
December1st to 15thDay
12%8%45%5%36%5%5%9%32%
1560
16th to endDay
16%9%5%8%6%345%6%7%25%
1664
January1st to 15thNight
9%8%35%5%36%5%5%8%37%
2716
16th to endNight
12%9%35%424447%40%
2610
February1st to 15thNight
11%8%36%6%36%5%46%37%
2276
16th to endNight
10%8%35%5%35%5%47%39%
1930
March1st to 15thNight
11%12%36%5%35%45%8%33%
2067
16th to endNight
12%8%36%5%25%5%5%9%35%
2058
April1st to 15thNight
8%9%46%6%35%45%7%37%
1799
16th to endNight
9%6%24322347%53%
1800
May1st to 15thNight
7%31432345%7%56%
1494
16th to endNight
8%5%24425%35%6%51%
1496
June1st to 15thNight
8%414324347%55%
1440
16th to endNight
422212225%73%
1440
July1st to 15thNight
12112435%74%
1440
16th to endNight
111123480%
1542
August1st to 15thNight
1122424474%
1620
16th to endNight
1111222382%
1884
September1st to 15thNight
1111123481%
1800
16th to endNight
323223236%68%
1954
October1st to 15thNight
5%313222345%64%
2160
16th to endNight
8%414333447%54%
2319
November1st to 15thNight
13%6%25%43446%8%39%
2470
16th to endNight
13%8%25%5%3445%8%38%
2728
December1st to 15thNight
13%8%25%5%34448%39%
2730
16th to endNight
13%10%47%6%35%45%7%31%
2912

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
47%9%16%18%7%1
1552
16th to endDay
46%5%12%20%8%6%
1717
February1st to 15thDay
44%6%17%21%9%
1576
16th to endDay
48%6%16%20%6%1
1544
March1st to 15thDay
50%7%14%16%9%
1891
16th to endDay
47%7%19%14%9%1
2166
April1st to 15thDay
51%5%11%20%10%
2149
16th to endDay
35%417%26%14%1
2160
May1st to 15thDay
29%5%12%26%20%5%
2454
16th to endDay
37%413%25%15%3
2619
June1st to 15thDay
30%6%11%20%23%7%
2520
16th to endDay
15%26%28%33%13%
2520
July1st to 15thDay
12%35%20%28%29%
2371
16th to endDay
11%3413%27%40%
2459
August1st to 15thDay
12%46%19%28%28%
2324
16th to endDay
7%1417%37%31%
2318
September1st to 15thDay
9%1316%33%35%
2160
16th to endDay
19%410%23%26%16%
2004
October1st to 15thDay
26%311%25%22%10%
1800
16th to endDay
34%5%12%20%20%5%
1903
November1st to 15thDay
45%6%16%18%11%2
1719
16th to endDay
46%6%14%17%12%2
1560
December1st to 15thDay
46%8%13%20%10%
1560
16th to endDay
56%7%10%17%6%
1664
January1st to 15thNight
42%8%18%18%10%1
2716
16th to endNight
42%6%11%20%10%7%
2610
February1st to 15thNight
45%7%16%18%10%2
2288
16th to endNight
43%7%17%21%8%2
1930
March1st to 15thNight
48%7%15%16%10%1
2067
16th to endNight
45%8%17%18%9%
2058
April1st to 15thNight
44%7%16%21%8%1
1799
16th to endNight
31%5%19%28%10%3
1800
May1st to 15thNight
27%6%14%27%19%5%
1495
16th to endNight
34%5%16%29%11%2
1496
June1st to 15thNight
30%6%14%27%18%4
1440
16th to endNight
15%28%35%30%7%
1440
July1st to 15thNight
11%38%22%30%23%
1360
16th to endNight
9%26%14%32%36%
1444
August1st to 15thNight
12%38%23%29%23%
1611
16th to endNight
8%15%19%36%28%
1884
September1st to 15thNight
8%2418%32%33%
1800
16th to endNight
17%48%25%24%20%
1954
October1st to 15thNight
22%411%26%25%10%
2160
16th to endNight
29%6%14%22%19%7%
2319
November1st to 15thNight
40%8%15%20%12%2
2470
16th to endNight
42%6%16%17%14%3
2728
December1st to 15thNight
42%7%12%23%13%1
2730
16th to endNight
50%6%13%19%9%1
2912

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
25%6%18%31%11%6%
90
16th to endDay
21%10%18%21%15%13%
220
February1st to 15thDay
17%13%19%23%20%5%
236
16th to endDay
18%15%22%27%12%3
232
March1st to 15thDay
22%18%25%15%14%3
270
16th to endDay
24%17%27%19%10%
288
April1st to 15thDay
14%21%24%20%9%8%
269
16th to endDay
15%18%29%19%10%7%
270
May1st to 15thDay
14%14%25%26%13%5%
288
16th to endDay
15%10%16%23%21%12%
330
June1st to 15thDay
10%13%22%24%17%11%
315
16th to endDay
410%22%28%20%14%
315
July1st to 15thDay
6%321%32%21%14%
305
16th to endDay
1322%33%24%14%
327
August1st to 15thDay
2219%30%25%19%
315
16th to endDay
35%18%27%26%19%
332
September1st to 15thDay
2419%26%29%18%
315
16th to endDay
6%9%20%25%29%9%
315
October1st to 15thDay
12%11%20%24%21%9%
315
16th to endDay
16%11%15%25%18%12%
319
November1st to 15thDay
16%8%18%34%17%3
135
16th to endDay
16%11%30%27%10%4
90
December1st to 15thDay
21%13%13%25%13%13%
90
16th to endDay
17%5%17%23%33%2
96
January1st to 15thNight
13%6%19%35%21%3
780
16th to endNight
16%5%18%31%22%5%
788
February1st to 15thNight
13%7%19%36%21%1
704
16th to endNight
13%9%18%39%16%2
632
March1st to 15thNight
16%11%23%28%17%3
720
16th to endNight
16%10%24%32%16%
768
April1st to 15thNight
12%10%25%33%17%1
719
16th to endNight
11%7%23%32%21%3
720
May1st to 15thNight
8%424%36%24%1
415
16th to endNight
10%418%38%25%2
375
June1st to 15thNight
9%218%40%26%1
360
16th to endNight
5%213%47%30%
360
July1st to 15thNight
17%46%43%
340
16th to endNight
16%49%39%2
406
August1st to 15thNight
1238%53%3
538
16th to endNight
219%40%42%4
738
September1st to 15thNight
119%34%46%6%
720
16th to endNight
5%113%37%36%5%
716
October1st to 15thNight
6%218%38%30%3
720
16th to endNight
10%315%34%29%7%
768
November1st to 15thNight
15%417%42%16%4
760
16th to endNight
16%8%19%32%20%3
780
December1st to 15thNight
16%6%17%30%24%3
780
16th to endNight
17%11%21%34%13%1
832
Page generated at 2018-01-21 09:19:22. Version ac04

Copyright 2018 A. Danko


Tulelake Clear Sky Chart |Charts Home