Chibougamau
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chibougamau clear sky chart from 2005-11-06 to 2024-11-05.

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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	17% 12% 4 11% 6% 6% 5% 4 5% 6% 23%	102284
	Night	16% 14% 5% 12% 7% 6% 5% 4 5% 5% 20%	96760
Transparency	Day	60% 7% 10% 16% 7%	105677
	Night	65% 6% 9% 14% 5%	101458
Seeing	Day	24% 13% 30% 22% 10% 2	15448
	Night	24% 11% 29% 26% 10% 1	23388

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	12% 17% 7% 19% 10% 9% 6% 4 4 4 8%	2517
	11th to 20th	Day	11% 14% 6% 17% 13% 11% 9% 4 5% 5% 6%	2520
	21st to end	Day	7% 14% 6% 21% 9% 7% 7% 5% 5% 6% 15%	2772
February	1st to 10th	Day	6% 13% 5% 14% 11% 9% 9% 7% 7% 6% 13%	1565
	11th to 20th	Day	9% 16% 5% 18% 10% 6% 7% 7% 6% 6% 10%	1663
	21st to end	Day	8% 16% 7% 11% 10% 7% 7% 4 7% 7% 15%	1556
March	1st to 10th	Day	17% 15% 4 11% 5% 5% 4 4 5% 5% 25%	3116
	11th to 20th	Day	9% 17% 6% 17% 10% 7% 6% 4 4 4 15%	3315
	21st to end	Day	9% 15% 6% 16% 8% 5% 6% 3 5% 5% 21%	4130
April	1st to 10th	Day	16% 17% 7% 11% 6% 5% 4 3 4 5% 23%	2280
	11th to 20th	Day	17% 11% 4 12% 5% 6% 5% 4 5% 6% 26%	2278
	21st to end	Day	17% 14% 4 11% 6% 5% 4 3 4 6% 27%	2608
May	1st to 10th	Day	16% 11% 5% 9% 6% 6% 5% 4 5% 7% 25%	4426
	11th to 20th	Day	16% 9% 3 9% 6% 5% 6% 4 6% 7% 28%	4398
	21st to end	Day	16% 9% 3 7% 5% 5% 5% 4 6% 8% 31%	4896
June	1st to 10th	Day	22% 10% 4 8% 6% 4 5% 3 5% 7% 28%	2850
	11th to 20th	Day	17% 8% 3 7% 6% 5% 5% 4 7% 7% 30%	3034
	21st to end	Day	19% 8% 3 8% 6% 5% 6% 4 6% 7% 28%	3040
July	1st to 10th	Day	19% 8% 3 7% 5% 6% 5% 5% 6% 8% 28%	4869
	11th to 20th	Day	15% 7% 2 7% 5% 6% 6% 5% 7% 8% 30%	4450
	21st to end	Day	16% 8% 3 7% 5% 6% 5% 4 7% 8% 30%	4814
August	1st to 10th	Day	18% 8% 4 8% 6% 5% 7% 5% 7% 8% 23%	4423
	11th to 20th	Day	18% 9% 3 8% 5% 5% 5% 4 6% 7% 30%	4359
	21st to end	Day	15% 8% 3 6% 4 4 5% 4 6% 8% 37%	4191
September	1st to 10th	Day	23% 10% 3 9% 5% 5% 5% 3 4 6% 27%	2280
	11th to 20th	Day	21% 12% 3 9% 5% 5% 4 4 5% 7% 25%	2236
	21st to end	Day	25% 13% 3 8% 4 4 4 3 4 5% 27%	2085
October	1st to 10th	Day	23% 12% 5% 8% 5% 4 4 3 4 6% 26%	1900
	11th to 20th	Day	30% 21% 5% 10% 5% 4 4 2 3 2 13%	1819
	21st to end	Day	27% 18% 7% 12% 6% 5% 3 2 2 5% 12%	1881
November	1st to 10th	Day	21% 26% 7% 13% 6% 3 3 2 3 3 12%	1632
	11th to 20th	Day	22% 24% 8% 14% 7% 4 4 2 2 3 9%	1520
	21st to end	Day	20% 25% 9% 17% 7% 5% 4 2 3 3 5%	1387
December	1st to 10th	Day	15% 24% 8% 16% 7% 8% 5% 4 3 3 8%	1330
	11th to 20th	Day	16% 16% 7% 16% 8% 7% 7% 4 5% 4 12%	1668
	21st to end	Day	13% 17% 9% 17% 11% 8% 6% 4 4 4 7%	2476
January	1st to 10th	Night	13% 18% 8% 16% 9% 9% 7% 3 4 4 8%	4429
	11th to 20th	Night	10% 16% 6% 19% 11% 9% 8% 4 5% 5% 8%	4440
	21st to end	Night	7% 15% 9% 18% 7% 8% 8% 5% 6% 4 13%	4884
February	1st to 10th	Night	8% 13% 5% 11% 9% 10% 10% 6% 8% 6% 14%	2613
	11th to 20th	Night	9% 18% 6% 13% 10% 7% 8% 6% 5% 6% 12%	2403
	21st to end	Night	8% 15% 5% 14% 10% 6% 6% 7% 6% 6% 18%	1897
March	1st to 10th	Night	13% 16% 5% 10% 6% 5% 6% 6% 5% 5% 23%	3724
	11th to 20th	Night	12% 19% 6% 17% 8% 6% 6% 4 5% 4 14%	3641
	21st to end	Night	12% 16% 6% 13% 6% 5% 5% 4 5% 5% 23%	3501
April	1st to 10th	Night	17% 15% 5% 10% 7% 4 5% 3 4 5% 25%	1900
	11th to 20th	Night	13% 13% 5% 10% 7% 5% 4 4 4 6% 29%	1849
	21st to end	Night	18% 11% 5% 9% 5% 4 4 3 4 4 33%	1589
May	1st to 10th	Night	17% 12% 3 9% 6% 5% 4 3 5% 6% 29%	2514
	11th to 20th	Night	16% 12% 4 7% 4 5% 5% 4 5% 6% 32%	2495
	21st to end	Night	21% 11% 3 9% 5% 5% 4 3 5% 7% 26%	2676
June	1st to 10th	Night	21% 10% 2 8% 5% 4 4 4 5% 6% 30%	1330
	11th to 20th	Night	17% 8% 3 8% 4 5% 5% 4 6% 7% 32%	1140
	21st to end	Night	17% 7% 3 7% 5% 5% 4 4 6% 6% 37%	1140
July	1st to 10th	Night	18% 9% 3 9% 5% 4 4 4 5% 6% 32%	2100
	11th to 20th	Night	18% 8% 3 7% 5% 5% 5% 3 6% 8% 33%	2508
	21st to end	Night	15% 7% 3 8% 5% 4 6% 4 7% 9% 34%	2739
August	1st to 10th	Night	17% 6% 3 7% 5% 5% 5% 5% 6% 8% 33%	2506
	11th to 20th	Night	16% 9% 3 7% 5% 4 4 4 6% 7% 35%	2470
	21st to end	Night	15% 8% 2 7% 5% 4 4 4 5% 7% 39%	3429
September	1st to 10th	Night	23% 8% 3 7% 5% 5% 3 3 4 6% 33%	1900
	11th to 20th	Night	22% 10% 3 8% 5% 4 5% 3 5% 6% 29%	1943
	21st to end	Night	21% 11% 3 9% 5% 5% 3 3 4 5% 31%	2092
October	1st to 10th	Night	21% 12% 4 7% 4 5% 5% 4 5% 6% 29%	2280
	11th to 20th	Night	28% 19% 5% 9% 5% 4 4 3 4 4 15%	2361
	21st to end	Night	29% 18% 6% 10% 5% 4 4 3 3 4 14%	2717
November	1st to 10th	Night	25% 22% 6% 13% 5% 5% 4 3 3 3 11%	2546
	11th to 20th	Night	18% 21% 7% 15% 8% 5% 5% 3 4 3 9%	2660
	21st to end	Night	18% 25% 9% 16% 9% 6% 4 3 2 2 6%	2791
December	1st to 10th	Night	15% 22% 8% 17% 9% 6% 5% 3 3 3 7%	2850
	11th to 20th	Night	16% 18% 6% 13% 10% 8% 6% 4 5% 4 9%	3531
	21st to end	Night	13% 16% 7% 20% 11% 7% 5% 3 4 3 8%	5172

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	80% 3 6% 9% 1	2518
	11th to 20th	Day	80% 5% 4 7% 3	2520
	21st to end	Day	69% 4 8% 11% 8%	2772
February	1st to 10th	Day	67% 5% 6% 13% 8%	1565
	11th to 20th	Day	72% 6% 8% 10% 5%	1672
	21st to end	Day	66% 5% 7% 13% 8%	1556
March	1st to 10th	Day	61% 4 5% 17% 12% 1	3119
	11th to 20th	Day	70% 6% 6% 12% 5% 1	3315
	21st to end	Day	63% 6% 7% 11% 11% 2	4130
April	1st to 10th	Day	64% 5% 9% 13% 8% 1	2280
	11th to 20th	Day	58% 6% 9% 16% 10% 1	2278
	21st to end	Day	58% 7% 7% 15% 13% 1	2608
May	1st to 10th	Day	54% 11% 11% 17% 7%	4440
	11th to 20th	Day	50% 10% 12% 20% 7% 1	4402
	21st to end	Day	47% 8% 12% 20% 11% 1	4896
June	1st to 10th	Day	56% 6% 8% 19% 11%	2850
	11th to 20th	Day	50% 8% 11% 18% 12% 2	3034
	21st to end	Day	53% 8% 10% 19% 10%	3040
July	1st to 10th	Day	51% 7% 13% 22% 5%	4795
	11th to 20th	Day	47% 8% 15% 22% 8% 1	4374
	21st to end	Day	49% 8% 14% 21% 8%	4661
August	1st to 10th	Day	54% 9% 14% 20% 3	4409
	11th to 20th	Day	51% 7% 15% 22% 5%	4401
	21st to end	Day	44% 7% 11% 29% 10%	4191
September	1st to 10th	Day	57% 6% 12% 16% 8%	2280
	11th to 20th	Day	57% 7% 15% 16% 4	2236
	21st to end	Day	60% 6% 13% 18% 4	2085
October	1st to 10th	Day	60% 6% 13% 16% 4	3160
	11th to 20th	Day	72% 4 10% 13% 1	2996
	21st to end	Day	80% 5% 8% 5% 2	3081
November	1st to 10th	Day	78% 5% 8% 7% 2 1	1632
	11th to 20th	Day	83% 4 6% 5% 1	1520
	21st to end	Day	88% 3 6% 3	1387
December	1st to 10th	Day	84% 3 4 8% 1	1330
	11th to 20th	Day	75% 5% 5% 11% 4 1	1668
	21st to end	Day	80% 5% 5% 5% 4 1	2476
January	1st to 10th	Night	80% 4 7% 8% 1	4429
	11th to 20th	Night	78% 5% 6% 8% 3	4440
	21st to end	Night	70% 5% 6% 13% 6%	4884
February	1st to 10th	Night	66% 6% 8% 12% 8%	2613
	11th to 20th	Night	72% 6% 7% 10% 4	2405
	21st to end	Night	64% 6% 7% 15% 7%	1897
March	1st to 10th	Night	61% 6% 6% 17% 10% 1	3734
	11th to 20th	Night	71% 6% 6% 12% 5%	3642
	21st to end	Night	61% 5% 9% 17% 7% 1	3501
April	1st to 10th	Night	61% 5% 9% 14% 9% 2	1900
	11th to 20th	Night	55% 6% 9% 20% 9% 1	1849
	21st to end	Night	55% 5% 8% 17% 13% 2	1589
May	1st to 10th	Night	50% 10% 12% 18% 9% 2	2520
	11th to 20th	Night	47% 9% 13% 21% 9% 1	2496
	21st to end	Night	54% 7% 9% 17% 13%	2677
June	1st to 10th	Night	52% 6% 10% 18% 12% 1	1330
	11th to 20th	Night	48% 8% 10% 20% 12% 1	1140
	21st to end	Night	46% 7% 13% 24% 9%	1140
July	1st to 10th	Night	51% 5% 10% 27% 6%	2065
	11th to 20th	Night	48% 6% 15% 20% 10%	2461
	21st to end	Night	47% 7% 12% 30% 3	2651
August	1st to 10th	Night	46% 9% 17% 24% 4	2496
	11th to 20th	Night	46% 7% 18% 23% 6%	2494
	21st to end	Night	44% 7% 13% 28% 8%	3429
September	1st to 10th	Night	55% 5% 11% 20% 8%	1900
	11th to 20th	Night	55% 8% 15% 17% 5%	1943
	21st to end	Night	56% 5% 15% 19% 5%	2092
October	1st to 10th	Night	59% 7% 13% 16% 4 1	3800
	11th to 20th	Night	72% 4 11% 10% 2 1	3923
	21st to end	Night	75% 4 11% 7% 2	4467
November	1st to 10th	Night	79% 5% 6% 7% 3	2546
	11th to 20th	Night	81% 4 8% 6% 1	2660
	21st to end	Night	87% 3 6% 4	2791
December	1st to 10th	Night	83% 4 6% 7% 1	2850
	11th to 20th	Night	76% 5% 7% 10% 3	3532
	21st to end	Night	79% 4 7% 6% 3 1	5172

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	14% 15% 39% 27% 3 1	180
	11th to 20th	Day	19% 11% 34% 18% 14% 3	180
	21st to end	Day	16% 10% 31% 28% 13% 2	198
February	1st to 10th	Day	7% 19% 40% 27% 6% 1	202
	11th to 20th	Day	17% 12% 41% 22% 7% 1	270
	21st to end	Day	18% 15% 40% 19% 7% 1	368
March	1st to 10th	Day	17% 15% 32% 25% 10% 1	460
	11th to 20th	Day	20% 14% 34% 22% 9% 2	460
	21st to end	Day	24% 14% 30% 25% 5% 2	506
April	1st to 10th	Day	22% 15% 31% 20% 10% 3	460
	11th to 20th	Day	22% 15% 29% 25% 6% 3	452
	21st to end	Day	23% 15% 35% 18% 6% 2	460
May	1st to 10th	Day	22% 13% 32% 20% 10% 2	463
	11th to 20th	Day	23% 12% 27% 24% 12% 3	487
	21st to end	Day	22% 14% 33% 23% 7% 1	562
June	1st to 10th	Day	27% 11% 30% 22% 9% 2	680
	11th to 20th	Day	20% 12% 32% 23% 11% 2	864
	21st to end	Day	21% 9% 26% 29% 12% 2	870
July	1st to 10th	Day	22% 9% 29% 26% 12% 2	741
	11th to 20th	Day	21% 9% 25% 28% 14% 3	493
	21st to end	Day	23% 7% 26% 23% 15% 5%	532
August	1st to 10th	Day	23% 11% 24% 23% 14% 4	486
	11th to 20th	Day	22% 8% 24% 24% 15% 8%	479
	21st to end	Day	23% 10% 26% 22% 11% 8%	539
September	1st to 10th	Day	30% 11% 28% 19% 10% 2	490
	11th to 20th	Day	23% 13% 30% 22% 9% 3	490
	21st to end	Day	29% 12% 26% 18% 11% 3	490
October	1st to 10th	Day	28% 14% 26% 20% 11% 2	490
	11th to 20th	Day	36% 17% 23% 16% 6% 2	447
	21st to end	Day	34% 16% 28% 16% 6%	429
November	1st to 10th	Day	38% 16% 32% 13% 2	302
	11th to 20th	Day	33% 18% 28% 14% 7%	180
	21st to end	Day	37% 13% 32% 12% 5% 1	180
December	1st to 10th	Day	26% 12% 23% 21% 16% 3	180
	11th to 20th	Day	24% 22% 27% 14% 11% 2	180
	21st to end	Day	20% 15% 34% 22% 7% 3	198
January	1st to 10th	Night	21% 11% 33% 26% 9% 1	760
	11th to 20th	Night	19% 14% 34% 23% 9% 1	760
	21st to end	Night	14% 8% 31% 32% 14% 1	836
February	1st to 10th	Night	12% 11% 32% 34% 9% 2	760
	11th to 20th	Night	19% 11% 30% 30% 10% 1	743
	21st to end	Night	17% 13% 33% 25% 11% 1	628
March	1st to 10th	Night	16% 13% 31% 30% 9% 1	760
	11th to 20th	Night	19% 13% 31% 28% 8% 1	760
	21st to end	Night	22% 12% 35% 25% 6% 1	836
April	1st to 10th	Night	24% 11% 30% 26% 9%	760
	11th to 20th	Night	19% 12% 32% 26% 10%	725
	21st to end	Night	23% 7% 34% 26% 8% 1	449
May	1st to 10th	Night	27% 5% 31% 27% 10% 1	380
	11th to 20th	Night	19% 9% 33% 25% 12% 2	374
	21st to end	Night	25% 9% 30% 28% 7%	411
June	1st to 10th	Night	24% 7% 29% 28% 10%	380
	11th to 20th	Night	21% 7% 29% 32% 11% 1	380
	21st to end	Night	20% 8% 24% 35% 12% 1	380
July	1st to 10th	Night	24% 6% 27% 32% 9% 1	370
	11th to 20th	Night	18% 4 26% 37% 15% 1	368
	21st to end	Night	23% 5% 19% 36% 17% 1	416
August	1st to 10th	Night	23% 4 24% 26% 22% 2	378
	11th to 20th	Night	20% 7% 20% 30% 22% 2	376
	21st to end	Night	23% 9% 22% 27% 16% 3	802
September	1st to 10th	Night	28% 6% 26% 26% 13% 1	760
	11th to 20th	Night	28% 10% 24% 27% 9% 2	760
	21st to end	Night	27% 10% 28% 25% 9% 1	760
October	1st to 10th	Night	26% 11% 30% 23% 9% 1	760
	11th to 20th	Night	37% 11% 26% 19% 5% 2	760
	21st to end	Night	39% 11% 25% 18% 6%	836
November	1st to 10th	Night	36% 15% 25% 17% 6% 1	760
	11th to 20th	Night	28% 15% 32% 18% 6%	760
	21st to end	Night	28% 17% 30% 18% 6% 1	823
December	1st to 10th	Night	25% 11% 32% 22% 9% 1	850
	11th to 20th	Night	22% 13% 32% 21% 9% 2	850
	21st to end	Night	24% 13% 31% 23% 8% 1	917

Page generated at 2024-11-03 02:11:25. Version ac07

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