The Pas
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the The Pas clear sky chart from 2005-11-05 to 2017-09-23.

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
33%
15868
10%
46708
6%
15830
37%
15830
18%
33662

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%
896
9%
2851
6%
895
30%
895
11%
2219
January16th to endNight
21%
960
9%
2751
3%
960
26%
960
11%
2197
February1st to 15thNight
30%
875
12%
2464
4%
875
37%
875
17%
1822
February16th to endNight
34%
693
12%
1996
6%
693
38%
693
17%
1487
March1st to 15thNight
37%
720
16%
2160
11%
720
42%
720
20%
1507
March16th to endNight
38%
585
17%
2028
14%
585
47%
585
20%
1326
April1st to 15thNight
43%
539
17%
1732
14%
539
49%
539
25%
1100
April16th to endNight
39%
540
16%
1557
9%
540
43%
540
25%
1033
May1st to 15thNight
34%
540
7%
1347
3%
540
36%
540
25%
975
May16th to endNight
38%
562
1%
1311
1%
561
39%
561
30%
915
June1st to 15thNight
41%
372
0%
1092
0%
372
41%
372
25%
726
June16th to endNight
44%
360
0%
1080
0%
360
44%
360
21%
744
July1st to 15thNight
45%
340
0%
1020
0%
340
45%
340
30%
606
July16th to endNight
54%
533
2%
1230
1%
500
55%
500
36%
795
August1st to 15thNight
55%
539
9%
1432
4%
536
58%
536
40%
854
August16th to endNight
48%
573
15%
1663
9%
573
52%
573
34%
989
September1st to 15thNight
44%
540
14%
1791
13%
540
49%
540
27%
1072
September16th to endNight
34%
516
15%
1903
13%
516
42%
516
19%
1211
October1st to 15thNight
31%
670
14%
1990
6%
670
38%
670
19%
1397
October16th to endNight
24%
880
13%
2288
5%
880
29%
880
15%
1775
November1st to 15thNight
23%
875
9%
2520
4%
875
27%
875
12%
2009
November16th to endNight
20%
900
6%
2700
3%
900
24%
900
10%
2193
December1st to 15thNight
23%
900
5%
2730
2%
900
26%
900
10%
2237
December16th to endNight
24%
960
9%
3072
5%
960
29%
960
9%
2473

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
14%9%47%6%35%5%5%6%31%
48238
Night
12%10%48%7%35%5%5%6%30%
46843
Cloud CoverDay
13%9%47%6%35%5%5%7%30%
48246
Night
12%10%48%7%35%5%5%6%30%
46847
Cloud CoverDay
14%9%37%6%35%5%5%7%31%
48246
Night
13%10%48%6%35%5%5%6%30%
46848
TransparencyDay
52%314%21%7%
47889
Night
54%314%20%7%
46708
SeeingDay
19%8%29%25%12%4
6322
Night
18%7%27%29%13%2
15878

By Month

Percentage Cloud Cover NE (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
7%15%8%10%8%37%8%8%5%15%
1086
16th to endDay
11%18%6%9%6%37%46%5%19%
1473
February1st to 15thDay
8%9%38%8%5%10%10%6%7%20%
1400
16th to endDay
7%11%6%11%10%39%7%46%21%
1487
March1st to 15thDay
11%11%5%7%6%36%5%5%6%29%
1790
16th to endDay
9%8%5%8%7%35%5%46%33%
2195
April1st to 15thDay
10%9%46%5%4446%6%37%
2216
16th to endDay
11%7%26%7%34447%39%
2400
May1st to 15thDay
15%10%46%6%35%45%5%31%
2604
16th to endDay
18%7%35%5%2445%7%36%
2803
June1st to 15thDay
18%7%37%5%45%5%5%6%30%
2865
16th to endDay
18%7%36%7%35%6%6%6%28%
2880
July1st to 15thDay
14%5%25%5%35%5%5%8%38%
2880
16th to endDay
12%5%35%5%345%6%9%37%
2851
August1st to 15thDay
12%4245%35%5%5%8%40%
2520
16th to endDay
15%5%25%43445%8%39%
2539
September1st to 15thDay
16%5%36%5%3445%8%37%
2168
16th to endDay
17%8%35%5%33448%36%
1893
October1st to 15thDay
20%15%37%42435%6%25%
1628
16th to endDay
20%18%6%8%6%23336%20%
1584
November1st to 15thDay
18%18%7%8%6%3343421%
1337
16th to endDay
9%14%6%14%10%45%5%3418%
1260
December1st to 15thDay
9%13%6%12%12%5%8%5%45%16%
1227
16th to endDay
10%14%6%14%10%5%6%5%7%414%
1152
January1st to 15thNight
7%14%6%11%9%5%7%8%6%418%
2851
16th to endNight
11%15%6%11%7%47%6%5%419%
2751
February1st to 15thNight
7%10%48%8%6%8%6%5%6%27%
2460
16th to endNight
7%11%6%10%9%46%6%45%28%
1996
March1st to 15thNight
12%10%5%7%6%3346%6%33%
2147
16th to endNight
9%8%47%6%36%5%6%8%33%
2028
April1st to 15thNight
11%9%36%4345%5%6%39%
1732
16th to endNight
8%10%35%7%4445%6%39%
1557
May1st to 15thNight
19%7%36%6%2435%6%35%
1347
16th to endNight
17%5%26%425%347%40%
1310
June1st to 15thNight
16%6%36%5%3445%7%36%
1092
16th to endNight
15%7%245%35%49%8%31%
1080
July1st to 15thNight
12%5%244235%48%46%
1080
16th to endNight
10%5%23425%47%10%44%
1315
August1st to 15thNight
11%3133245%5%9%49%
1440
16th to endNight
13%313413449%48%
1663
September1st to 15thNight
13%5%2442435%7%45%
1791
16th to endNight
17%7%25%435%36%6%37%
1903
October1st to 15thNight
19%12%35%423335%35%
1990
16th to endNight
18%14%47%6%34435%26%
2288
November1st to 15thNight
17%16%7%9%7%3344421%
2520
16th to endNight
10%16%7%12%11%45%445%18%
2700
December1st to 15thNight
9%14%7%12%10%5%6%6%5%5%15%
2730
16th to endNight
12%15%6%12%10%45%5%5%5%16%
3072

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
6%16%8%9%8%38%6%10%5%15%
1086
16th to endDay
12%17%6%8%7%37%5%6%5%18%
1473
February1st to 15thDay
8%8%48%7%5%12%9%6%7%20%
1400
16th to endDay
6%11%5%10%10%48%7%6%7%20%
1487
March1st to 15thDay
12%11%5%8%6%36%45%6%28%
1800
16th to endDay
9%8%5%9%7%35%5%5%6%32%
2193
April1st to 15thDay
9%9%46%5%3446%7%36%
2216
16th to endDay
11%7%35%7%35%45%7%38%
2400
May1st to 15thDay
15%9%37%6%35%5%46%31%
2604
16th to endDay
18%6%35%5%3445%6%37%
2803
June1st to 15thDay
18%8%37%5%35%5%5%6%30%
2865
16th to endDay
18%7%36%6%45%6%6%6%28%
2880
July1st to 15thDay
13%6%35%435%5%6%7%38%
2880
16th to endDay
12%6%35%5%245%6%9%38%
2851
August1st to 15thDay
12%425%5%35%5%6%8%40%
2520
16th to endDay
15%5%25%5%2445%8%39%
2539
September1st to 15thDay
15%5%36%6%3445%7%37%
2168
16th to endDay
16%8%25%5%33448%35%
1893
October1st to 15thDay
19%15%47%43435%6%25%
1628
16th to endDay
20%17%6%9%6%23345%20%
1584
November1st to 15thDay
18%17%6%9%7%34345%21%
1337
16th to endDay
9%14%7%14%11%445%35%18%
1260
December1st to 15thDay
9%13%7%12%11%5%8%5%46%15%
1227
16th to endDay
10%14%7%13%9%6%6%47%5%13%
1152
January1st to 15thNight
7%14%6%10%10%47%7%6%5%18%
2851
16th to endNight
12%14%6%11%6%47%6%4419%
2751
February1st to 15thNight
7%10%48%8%5%9%6%5%6%27%
2453
16th to endNight
6%11%6%10%10%37%5%45%27%
1996
March1st to 15thNight
12%10%5%8%5%3346%6%33%
2160
16th to endNight
8%8%5%6%6%46%5%5%8%33%
2026
April1st to 15thNight
11%10%36%5%2445%6%40%
1732
16th to endNight
8%8%46%6%45%45%5%40%
1557
May1st to 15thNight
18%8%35%6%34346%35%
1346
16th to endNight
17%5%26%324446%40%
1311
June1st to 15thNight
16%6%25%5%35%448%36%
1092
16th to endNight
15%7%35%5%25%5%7%9%31%
1080
July1st to 15thNight
12%5%2442346%7%46%
1080
16th to endNight
9%5%23435%47%8%45%
1315
August1st to 15thNight
11%32322446%9%48%
1440
16th to endNight
13%31432345%9%48%
1663
September1st to 15thNight
12%5%25%43346%6%44%
1791
16th to endNight
17%6%25%5%3445%7%36%
1903
October1st to 15thNight
18%11%46%433336%35%
1990
16th to endNight
19%13%48%5%3444427%
2288
November1st to 15thNight
17%17%6%10%7%3344421%
2520
16th to endNight
10%16%6%11%11%5%5%445%18%
2700
December1st to 15thNight
9%14%7%12%11%5%7%5%5%5%15%
2730
16th to endNight
12%15%7%12%9%46%5%5%5%16%
3072

Percentage Cloud Cover SE (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
7%15%7%9%8%47%5%9%6%16%
1086
16th to endDay
13%15%6%9%6%47%5%6%6%18%
1473
February1st to 15thDay
9%8%48%8%5%10%8%7%7%21%
1400
16th to endDay
7%10%5%11%9%5%8%7%5%6%22%
1487
March1st to 15thDay
13%10%49%5%35%5%46%29%
1800
16th to endDay
9%10%46%7%35%5%5%8%33%
2193
April1st to 15thDay
9%9%36%6%2446%7%37%
2216
16th to endDay
11%7%26%6%35%45%7%39%
2400
May1st to 15thDay
16%8%36%6%35%445%33%
2604
16th to endDay
19%6%25%42445%7%37%
2803
June1st to 15thDay
18%8%35%5%35%5%6%5%32%
2865
16th to endDay
18%6%36%6%36%5%5%7%29%
2880
July1st to 15thDay
13%5%25%425%6%6%8%39%
2880
16th to endDay
12%425%435%5%6%9%40%
2851
August1st to 15thDay
13%3245%25%5%6%7%42%
2520
16th to endDay
14%4245%3445%8%40%
2539
September1st to 15thDay
16%5%25%5%45%45%7%37%
2168
16th to endDay
17%8%35%5%3445%8%36%
1893
October1st to 15thDay
20%15%37%5%34346%25%
1628
16th to endDay
21%17%6%8%6%24245%18%
1584
November1st to 15thDay
20%14%5%10%6%43445%20%
1337
16th to endDay
10%14%6%14%10%46%44418%
1260
December1st to 15thDay
9%12%7%11%12%47%5%5%5%16%
1227
16th to endDay
12%12%6%12%12%6%6%447%14%
1152
January1st to 15thNight
9%13%6%10%8%47%7%6%6%19%
2851
16th to endNight
12%14%7%10%7%46%6%5%420%
2751
February1st to 15thNight
7%9%5%7%9%5%8%6%5%6%27%
2453
16th to endNight
8%9%6%11%9%46%5%5%6%27%
1996
March1st to 15thNight
13%10%48%6%2345%5%34%
2160
16th to endNight
9%7%46%6%35%5%6%7%34%
2028
April1st to 15thNight
12%9%35%5%335%47%40%
1732
16th to endNight
9%9%27%5%35%45%5%40%
1557
May1st to 15thNight
19%7%46%5%24446%35%
1346
16th to endNight
18%5%15%32445%6%41%
1310
June1st to 15thNight
17%425%5%34448%38%
1092
16th to endNight
16%6%45%4346%8%9%32%
1080
July1st to 15thNight
13%415%5%2345%8%45%
1080
16th to endNight
10%415%32448%8%45%
1315
August1st to 15thNight
10%42331346%10%49%
1440
16th to endNight
14%41331445%8%48%
1663
September1st to 15thNight
14%5%2442345%8%43%
1791
16th to endNight
17%6%245%35%45%7%37%
1903
October1st to 15thNight
18%13%35%423345%35%
1990
16th to endNight
20%13%5%7%5%33445%26%
2288
November1st to 15thNight
18%16%6%10%6%34345%20%
2520
16th to endNight
10%16%6%13%10%45%446%17%
2700
December1st to 15thNight
10%14%7%11%10%5%6%6%5%6%15%
2730
16th to endNight
13%15%6%12%9%45%45%5%16%
3072

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
64%314%15%2
1086
16th to endDay
65%39%16%5%
1473
February1st to 15thDay
58%5%14%15%6%
1400
16th to endDay
60%49%20%5%
1487
March1st to 15thDay
55%411%19%7%1
1800
16th to endDay
51%312%23%7%1
2195
April1st to 15thDay
46%214%22%12%1
2216
16th to endDay
44%311%26%13%
2400
May1st to 15thDay
54%29%22%9%1
2604
16th to endDay
47%38%26%13%
2807
June1st to 15thDay
53%39%20%12%
2865
16th to endDay
53%5%13%22%4
2880
July1st to 15thDay
41%316%29%8%
2711
16th to endDay
42%420%25%5%
2673
August1st to 15thDay
40%424%26%3
2504
16th to endDay
42%426%23%2
2539
September1st to 15thDay
45%320%21%7%
2168
16th to endDay
47%319%23%5%
1893
October1st to 15thDay
59%314%19%2
1628
16th to endDay
67%312%14%2
1584
November1st to 15thDay
67%212%12%4
1337
16th to endDay
68%314%11%1
1260
December1st to 15thDay
70%314%8%3
1227
16th to endDay
69%39%16%1
1152
January1st to 15thNight
63%411%17%3
2851
16th to endNight
65%311%15%3
2751
February1st to 15thNight
55%313%19%7%
2464
16th to endNight
57%313%18%7%
1996
March1st to 15thNight
50%311%23%9%1
2160
16th to endNight
47%314%23%9%1
2028
April1st to 15thNight
44%112%22%14%3
1732
16th to endNight
45%27%23%17%2
1557
May1st to 15thNight
50%211%19%13%2
1347
16th to endNight
43%39%24%17%2
1311
June1st to 15thNight
46%212%22%15%
1092
16th to endNight
45%8%18%21%5%
1080
July1st to 15thNight
36%317%29%13%
1020
16th to endNight
36%323%28%7%
1230
August1st to 15thNight
30%424%34%5%
1432
16th to endNight
33%423%30%7%
1663
September1st to 15thNight
38%318%29%9%
1791
16th to endNight
46%316%23%10%
1903
October1st to 15thNight
51%315%24%4
1990
16th to endNight
60%313%18%4
2288
November1st to 15thNight
66%213%13%4
2520
16th to endNight
68%314%11%2
2700
December1st to 15thNight
67%414%10%2
2730
16th to endNight
69%210%15%2
3072

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
49%35%43%6%
62
16th to endDay
26%330%30%10%
96
February1st to 15thDay
10%11%47%21%7%2
90
16th to endDay
14%11%27%24%19%2
81
March1st to 15thDay
20%8%30%28%11%1
90
16th to endDay
18%12%27%23%13%4
188
April1st to 15thDay
20%8%37%24%8%1
335
16th to endDay
14%9%34%25%13%2
450
May1st to 15thDay
23%11%31%22%8%1
468
16th to endDay
21%9%25%28%11%3
517
June1st to 15thDay
22%10%29%19%12%5%
495
16th to endDay
24%7%26%22%13%6%
495
July1st to 15thDay
17%9%26%28%12%5%
475
16th to endDay
15%8%27%25%16%6%
515
August1st to 15thDay
16%5%23%26%18%10%
493
16th to endDay
18%5%26%31%15%2
523
September1st to 15thDay
21%10%34%22%9%1
323
16th to endDay
29%12%24%18%13%1
111
October1st to 15thDay
33%12%28%16%7%1
90
16th to endDay
40%10%22%19%5%1
96
November1st to 15thDay
21%12%27%24%12%2
90
16th to endDay
23%427%35%6%2
90
December1st to 15thDay
16%323%30%20%5%
85
16th to endDay
4446%37%6%
64
January1st to 15thNight
13%10%31%29%13%2
900
16th to endNight
20%10%34%26%7%
960
February1st to 15thNight
12%7%33%31%13%1
880
16th to endNight
12%6%28%31%18%2
693
March1st to 15thNight
16%8%25%30%16%2
720
16th to endNight
12%6%29%30%16%4
585
April1st to 15thNight
16%6%23%34%16%2
539
16th to endNight
14%7%28%33%14%2
540
May1st to 15thNight
23%7%26%28%11%2
540
16th to endNight
19%8%29%31%10%
563
June1st to 15thNight
20%425%31%16%1
372
16th to endNight
22%5%19%36%15%1
360
July1st to 15thNight
17%6%24%29%20%1
340
16th to endNight
12%322%35%20%4
533
August1st to 15thNight
13%422%32%22%4
539
16th to endNight
15%5%24%34%19%1
573
September1st to 15thNight
16%426%30%20%1
540
16th to endNight
22%8%26%30%10%
516
October1st to 15thNight
26%7%25%28%10%1
670
16th to endNight
28%10%25%24%9%1
880
November1st to 15thNight
25%8%26%25%11%2
875
16th to endNight
18%11%32%27%9%1
900
December1st to 15thNight
17%9%31%26%12%3
900
16th to endNight
21%8%26%24%14%5%
960
Page generated at 2017-09-24 08:15:54. Version ac04

Copyright 2017 A. Danko


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