Matane
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Matane clear sky chart from 2005-11-06 to 2026-08-15.

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% 11% 4 9% 6% 5% 5% 4 5% 6% 29%	144519
	Night	17% 14% 5% 11% 7% 6% 5% 4 5% 5% 22%	137631
Transparency	Day	55% 7% 13% 18% 7%	147955
	Night	62% 6% 11% 14% 6%	142285
Seeing	Day	23% 15% 29% 22% 9% 2	18451
	Night	24% 15% 28% 24% 8% 1	26150

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	14% 23% 8% 15% 9% 11% 6% 2 3 3 5%	4093
	11th to 20th	Day	9% 21% 10% 19% 13% 5% 4 3 4 4 7%	4284
	21st to end	Day	3 8% 5% 16% 12% 12% 12% 9% 5% 5% 14%	5124
February	1st to 10th	Day	9% 14% 4 12% 10% 8% 7% 5% 5% 6% 19%	1817
	11th to 20th	Day	11% 16% 6% 13% 7% 7% 6% 5% 4 5% 20%	1843
	21st to end	Day	9% 14% 4 9% 8% 7% 7% 4 5% 7% 27%	1678
March	1st to 10th	Day	14% 16% 5% 9% 7% 8% 8% 3 4 6% 19%	4666
	11th to 20th	Day	19% 18% 4 8% 5% 6% 6% 5% 6% 6% 18%	5090
	21st to end	Day	20% 16% 6% 10% 6% 5% 4 3 4 4 23%	5587
April	1st to 10th	Day	20% 13% 3 7% 6% 4 4 3 5% 6% 28%	2557
	11th to 20th	Day	18% 12% 4 6% 4 4 4 3 5% 7% 33%	2702
	21st to end	Day	21% 11% 3 7% 4 4 3 3 4 6% 33%	2730
May	1st to 10th	Day	23% 10% 3 8% 5% 4 4 3 5% 6% 30%	7698
	11th to 20th	Day	22% 8% 2 6% 4 4 4 4 5% 7% 34%	8610
	21st to end	Day	23% 9% 3 7% 4 4 4 3 4 6% 33%	9716
June	1st to 10th	Day	20% 8% 3 7% 5% 4 4 4 4 6% 34%	3150
	11th to 20th	Day	20% 6% 2 6% 4 4 4 4 5% 8% 36%	3150
	21st to end	Day	20% 8% 3 6% 5% 5% 5% 4 6% 8% 30%	3150
July	1st to 10th	Day	14% 7% 2 6% 4 4 5% 4 6% 8% 38%	8880
	11th to 20th	Day	15% 7% 3 7% 5% 4 5% 4 6% 8% 35%	8880
	21st to end	Day	10% 6% 3 7% 5% 5% 6% 4 6% 9% 40%	9313
August	1st to 10th	Day	13% 6% 2 6% 4 5% 5% 5% 7% 9% 39%	4474
	11th to 20th	Day	17% 6% 2 7% 4 4 5% 4 7% 8% 35%	4227
	21st to end	Day	15% 6% 2 6% 4 4 5% 4 6% 9% 41%	4675
September	1st to 10th	Day	19% 6% 2 5% 3 4 3 4 5% 7% 42%	2435
	11th to 20th	Day	22% 6% 2 5% 3 3 4 3 3 5% 44%	2200
	21st to end	Day	19% 8% 3 6% 4 4 4 4 4 7% 38%	2200
October	1st to 10th	Day	20% 8% 3 6% 4 4 5% 3 5% 6% 37%	2060
	11th to 20th	Day	27% 10% 2 6% 4 3 4 4 5% 6% 29%	1965
	21st to end	Day	26% 14% 3 6% 4 4 3 3 5% 7% 25%	1980
November	1st to 10th	Day	22% 14% 4 9% 6% 4 4 3 4 6% 24%	1725
	11th to 20th	Day	22% 17% 7% 12% 6% 3 4 3 4 4 17%	1680
	21st to end	Day	21% 20% 6% 14% 6% 5% 4 4 4 4 13%	1589
December	1st to 10th	Day	14% 21% 7% 19% 12% 6% 4 2 3 3 9%	2350
	11th to 20th	Day	16% 15% 7% 19% 11% 7% 5% 2 4 3 12%	2688
	21st to end	Day	13% 16% 5% 16% 12% 8% 6% 3 4 4 12%	3553
January	1st to 10th	Night	15% 25% 8% 15% 10% 8% 5% 2 3 2 7%	8831
	11th to 20th	Night	10% 18% 7% 20% 11% 6% 5% 3 4 4 10%	8615
	21st to end	Night	4 10% 6% 16% 10% 11% 13% 8% 5% 5% 13%	9057
February	1st to 10th	Night	8% 14% 5% 12% 9% 8% 7% 4 5% 6% 22%	2801
	11th to 20th	Night	12% 19% 7% 11% 7% 6% 6% 4 4 5% 20%	2663
	21st to end	Night	10% 16% 4 10% 8% 7% 5% 4 4 6% 26%	2126
March	1st to 10th	Night	16% 16% 4 9% 7% 7% 7% 4 5% 5% 21%	5393
	11th to 20th	Night	20% 19% 5% 11% 7% 5% 5% 3 5% 4 17%	5089
	21st to end	Night	24% 18% 4 8% 7% 4 3 3 3 4 22%	5587
April	1st to 10th	Night	22% 14% 4 11% 5% 4 3 3 3 6% 25%	2060
	11th to 20th	Night	22% 11% 2 7% 4 4 4 4 5% 6% 31%	1868
	21st to end	Night	25% 10% 4 5% 3 4 4 3 5% 5% 33%	1890
May	1st to 10th	Night	26% 10% 3 7% 4 4 3 3 5% 6% 31%	5203
	11th to 20th	Night	25% 9% 3 7% 4 4 4 3 5% 6% 30%	4336
	21st to end	Night	22% 10% 3 9% 5% 4 5% 4 5% 5% 30%	4491
June	1st to 10th	Night	21% 8% 3 7% 5% 4 4 4 6% 7% 30%	1470
	11th to 20th	Night	22% 7% 2 7% 5% 4 4 4 6% 7% 31%	1470
	21st to end	Night	21% 11% 3 7% 5% 5% 4 4 6% 6% 29%	1470
July	1st to 10th	Night	16% 7% 4 8% 5% 5% 6% 4 6% 6% 34%	4110
	11th to 20th	Night	16% 8% 3 9% 5% 5% 5% 5% 7% 9% 30%	4110
	21st to end	Night	11% 7% 3 8% 6% 5% 6% 4 7% 8% 36%	4776
August	1st to 10th	Night	17% 7% 3 8% 6% 6% 6% 5% 7% 9% 27%	2861
	11th to 20th	Night	15% 6% 3 8% 7% 5% 6% 5% 7% 9% 29%	2909
	21st to end	Night	19% 5% 2 6% 3 4 4 3 6% 6% 41%	3223
September	1st to 10th	Night	19% 6% 2 7% 5% 4 5% 3 5% 6% 38%	1962
	11th to 20th	Night	22% 7% 2 7% 4 3 4 3 4 6% 39%	2200
	21st to end	Night	20% 6% 2 5% 4 3 4 3 4 6% 44%	2200
October	1st to 10th	Night	21% 6% 3 6% 5% 4 4 3 5% 6% 38%	2340
	11th to 20th	Night	27% 11% 3 6% 4 3 4 4 4 6% 28%	2432
	21st to end	Night	25% 13% 3 8% 4 4 4 3 5% 6% 25%	2860
November	1st to 10th	Night	23% 15% 5% 9% 4 5% 4 3 4 6% 24%	2791
	11th to 20th	Night	22% 20% 7% 11% 4 3 3 3 3 5% 18%	2940
	21st to end	Night	19% 22% 7% 15% 7% 4 3 3 4 4 13%	3029
December	1st to 10th	Night	14% 21% 9% 22% 9% 6% 4 2 3 3 9%	5060
	11th to 20th	Night	17% 17% 5% 18% 12% 6% 4 3 3 3 11%	5741
	21st to end	Night	15% 17% 6% 15% 10% 7% 5% 4 5% 5% 12%	7667

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	85% 4 6% 3 2	4094
	11th to 20th	Day	81% 5% 8% 5% 2	4311
	21st to end	Day	69% 8% 10% 10% 4	5124
February	1st to 10th	Day	64% 8% 11% 13% 5%	1817
	11th to 20th	Day	66% 7% 11% 11% 4	1851
	21st to end	Day	57% 7% 10% 19% 7%	1678
March	1st to 10th	Day	65% 6% 12% 12% 4	4670
	11th to 20th	Day	66% 8% 9% 13% 4	5090
	21st to end	Day	65% 4 7% 15% 7% 2	5587
April	1st to 10th	Day	57% 6% 11% 15% 10% 1	2557
	11th to 20th	Day	51% 7% 11% 20% 11% 1	2702
	21st to end	Day	52% 6% 10% 19% 11% 2	2730
May	1st to 10th	Day	54% 7% 10% 18% 9% 1	7710
	11th to 20th	Day	48% 8% 12% 22% 9% 1	8614
	21st to end	Day	51% 6% 11% 19% 13%	9717
June	1st to 10th	Day	51% 7% 10% 20% 11% 2	3150
	11th to 20th	Day	46% 8% 13% 19% 12% 1	3150
	21st to end	Day	52% 9% 12% 16% 10% 1	3150
July	1st to 10th	Day	42% 6% 13% 27% 11%	8805
	11th to 20th	Day	46% 7% 20% 22% 5% 1	8799
	21st to end	Day	40% 7% 20% 26% 7%	9108
August	1st to 10th	Day	39% 9% 20% 26% 6%	4460
	11th to 20th	Day	46% 9% 23% 18% 5%	4266
	21st to end	Day	40% 8% 20% 22% 10%	4675
September	1st to 10th	Day	41% 7% 18% 25% 9%	2435
	11th to 20th	Day	43% 7% 15% 27% 9% 1	2200
	21st to end	Day	46% 6% 14% 25% 8%	2200
October	1st to 10th	Day	51% 7% 16% 20% 6%	3359
	11th to 20th	Day	55% 6% 13% 23% 4	3181
	21st to end	Day	54% 6% 17% 17% 6%	3180
November	1st to 10th	Day	62% 6% 13% 13% 5%	1725
	11th to 20th	Day	71% 7% 9% 10% 3	1680
	21st to end	Day	74% 6% 10% 7% 3	1589
December	1st to 10th	Day	80% 5% 8% 6% 1	2350
	11th to 20th	Day	77% 6% 6% 9% 2	2688
	21st to end	Day	72% 9% 8% 8% 3	3553
January	1st to 10th	Night	84% 5% 6% 4	8831
	11th to 20th	Night	76% 5% 8% 7% 3	8663
	21st to end	Night	70% 7% 9% 10% 4	9057
February	1st to 10th	Night	63% 7% 10% 12% 7% 1	2801
	11th to 20th	Night	67% 6% 10% 12% 5%	2666
	21st to end	Night	59% 7% 10% 16% 8%	2126
March	1st to 10th	Night	64% 5% 11% 13% 7%	5402
	11th to 20th	Night	69% 6% 10% 10% 5%	5090
	21st to end	Night	67% 4 7% 14% 8% 1	5587
April	1st to 10th	Night	62% 4 9% 12% 12% 1	2060
	11th to 20th	Night	53% 6% 8% 18% 14% 1	1868
	21st to end	Night	53% 5% 8% 20% 13% 2	1890
May	1st to 10th	Night	53% 6% 10% 16% 12% 2	5209
	11th to 20th	Night	54% 5% 9% 18% 12% 1	4337
	21st to end	Night	55% 6% 9% 17% 12% 1	4492
June	1st to 10th	Night	52% 7% 9% 19% 11% 1	1470
	11th to 20th	Night	50% 5% 13% 18% 12% 2	1470
	21st to end	Night	56% 7% 10% 16% 11% 1	1470
July	1st to 10th	Night	48% 6% 13% 24% 9%	4075
	11th to 20th	Night	48% 8% 18% 23% 3	4068
	21st to end	Night	43% 8% 18% 22% 8%	4666
August	1st to 10th	Night	50% 9% 17% 19% 5%	2851
	11th to 20th	Night	47% 10% 22% 14% 6%	2936
	21st to end	Night	43% 8% 14% 22% 13%	3223
September	1st to 10th	Night	45% 6% 14% 24% 10% 1	1962
	11th to 20th	Night	47% 6% 14% 23% 9% 1	2200
	21st to end	Night	42% 6% 13% 25% 14%	2200
October	1st to 10th	Night	49% 6% 12% 26% 7% 1	3821
	11th to 20th	Night	55% 5% 13% 23% 5%	3955
	21st to end	Night	57% 7% 14% 18% 4	4610
November	1st to 10th	Night	62% 6% 15% 13% 4 1	2791
	11th to 20th	Night	69% 6% 11% 10% 4	2940
	21st to end	Night	75% 7% 8% 6% 3 1	3029
December	1st to 10th	Night	79% 6% 9% 5% 1	5060
	11th to 20th	Night	78% 5% 7% 8% 2	5742
	21st to end	Night	70% 9% 10% 8% 3	7667

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	28% 20% 31% 16% 4	220
	11th to 20th	Day	23% 26% 26% 13% 10% 2	220
	21st to end	Day	16% 24% 35% 18% 7% 1	242
February	1st to 10th	Day	16% 22% 32% 18% 7% 3	357
	11th to 20th	Day	18% 23% 38% 16% 5%	426
	21st to end	Day	18% 21% 36% 19% 6%	419
March	1st to 10th	Day	23% 19% 32% 20% 6% 1	540
	11th to 20th	Day	25% 19% 31% 16% 7% 1	540
	21st to end	Day	26% 20% 30% 17% 6% 1	594
April	1st to 10th	Day	26% 22% 29% 18% 4 1	540
	11th to 20th	Day	26% 15% 36% 18% 4 1	532
	21st to end	Day	27% 18% 26% 19% 8% 2	540
May	1st to 10th	Day	28% 16% 29% 19% 7% 1	564
	11th to 20th	Day	23% 12% 30% 23% 11% 1	774
	21st to end	Day	27% 15% 27% 21% 9% 1	845
June	1st to 10th	Day	23% 11% 28% 28% 9% 1	780
	11th to 20th	Day	23% 11% 30% 25% 9% 1	780
	21st to end	Day	23% 10% 28% 28% 10% 2	780
July	1st to 10th	Day	17% 10% 31% 28% 12% 2	770
	11th to 20th	Day	16% 10% 29% 30% 14% 1	768
	21st to end	Day	17% 7% 27% 34% 14% 2	735
August	1st to 10th	Day	17% 7% 24% 34% 16% 3	566
	11th to 20th	Day	17% 7% 25% 30% 19% 3	535
	21st to end	Day	18% 9% 26% 27% 15% 4	583
September	1st to 10th	Day	21% 12% 25% 26% 13% 3	530
	11th to 20th	Day	23% 12% 28% 22% 13% 2	530
	21st to end	Day	20% 15% 30% 21% 11% 4	530
October	1st to 10th	Day	21% 15% 32% 22% 9% 2	453
	11th to 20th	Day	34% 17% 20% 19% 8% 2	420
	21st to end	Day	32% 19% 24% 16% 9% 1	462
November	1st to 10th	Day	30% 26% 27% 15% 2	425
	11th to 20th	Day	34% 21% 23% 17% 4 1	430
	21st to end	Day	29% 26% 25% 15% 5%	339
December	1st to 10th	Day	26% 23% 27% 15% 8% 1	220
	11th to 20th	Day	23% 28% 31% 15% 2	220
	21st to end	Day	21% 24% 29% 22% 4	242
January	1st to 10th	Night	26% 20% 33% 17% 4 1	950
	11th to 20th	Night	23% 22% 30% 18% 6% 1	911
	21st to end	Night	14% 22% 32% 24% 7% 1	924
February	1st to 10th	Night	14% 22% 33% 22% 8% 1	840
	11th to 20th	Night	24% 16% 32% 21% 6% 1	823
	21st to end	Night	18% 15% 36% 23% 8% 1	692
March	1st to 10th	Night	23% 15% 34% 22% 6% 1	840
	11th to 20th	Night	25% 21% 27% 19% 8% 1	840
	21st to end	Night	24% 16% 29% 23% 7% 1	924
April	1st to 10th	Night	29% 17% 29% 19% 6%	755
	11th to 20th	Night	27% 14% 25% 23% 9% 1	624
	21st to end	Night	30% 13% 23% 24% 8% 1	630
May	1st to 10th	Night	28% 11% 25% 27% 8%	630
	11th to 20th	Night	22% 9% 28% 28% 13% 1	509
	21st to end	Night	26% 9% 30% 26% 9%	455
June	1st to 10th	Night	25% 7% 22% 38% 8%	420
	11th to 20th	Night	23% 8% 26% 28% 15% 1	420
	21st to end	Night	23% 6% 28% 30% 12% 2	420
July	1st to 10th	Night	20% 7% 25% 35% 11% 1	410
	11th to 20th	Night	16% 7% 28% 36% 12% 1	408
	21st to end	Night	16% 6% 25% 39% 13% 1	460
August	1st to 10th	Night	17% 6% 21% 34% 20% 1	535
	11th to 20th	Night	17% 5% 21% 38% 18% 2	605
	21st to end	Night	18% 6% 22% 35% 17% 2	660
September	1st to 10th	Night	22% 9% 27% 29% 12% 1	654
	11th to 20th	Night	24% 9% 25% 26% 13% 2	800
	21st to end	Night	22% 11% 29% 26% 11% 1	800
October	1st to 10th	Night	23% 14% 28% 25% 9% 1	800
	11th to 20th	Night	34% 10% 24% 20% 11% 1	800
	21st to end	Night	32% 17% 24% 21% 6% 1	880
November	1st to 10th	Night	31% 19% 29% 16% 4 1	886
	11th to 20th	Night	30% 20% 26% 17% 5% 2	950
	21st to end	Night	29% 21% 27% 17% 6% 1	950
December	1st to 10th	Night	27% 19% 32% 16% 5% 1	950
	11th to 20th	Night	27% 24% 29% 16% 4	950
	21st to end	Night	24% 22% 27% 21% 4 1	1045

Page generated at 2026-08-12 03:37:18. Version ac07

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