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 2025-04-11.

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% 28%	112934
	Night	17% 14% 5% 11% 7% 5% 5% 4 5% 5% 22%	115473
Transparency	Day	55% 7% 13% 17% 7%	116417
	Night	63% 6% 11% 14% 6%	120155
Seeing	Day	23% 15% 29% 22% 9% 1	16544
	Night	25% 15% 28% 23% 8% 1	24558

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	16% 25% 8% 15% 9% 11% 3 2 3 4 4	3157
	11th to 20th	Day	9% 18% 10% 20% 15% 6% 4 3 4 4 8%	3282
	21st to end	Day	4 8% 3 13% 12% 13% 12% 8% 5% 5% 16%	3960
February	1st to 10th	Day	9% 14% 3 12% 10% 8% 7% 5% 5% 6% 19%	1730
	11th to 20th	Day	12% 16% 6% 13% 8% 7% 6% 5% 4 5% 20%	1753
	21st to end	Day	9% 14% 4 9% 8% 7% 7% 4 5% 7% 27%	1600
March	1st to 10th	Day	14% 16% 5% 9% 7% 8% 7% 3 4 6% 19%	4564
	11th to 20th	Day	19% 18% 4 7% 5% 6% 6% 5% 6% 6% 18%	4980
	21st to end	Day	20% 16% 6% 10% 6% 4 4 3 4 4 24%	5466
April	1st to 10th	Day	20% 13% 3 7% 6% 5% 4 3 5% 6% 27%	2435
	11th to 20th	Day	17% 11% 4 6% 4 4 4 3 5% 8% 34%	2442
	21st to end	Day	20% 11% 3 7% 4 4 3 3 4 6% 34%	2470
May	1st to 10th	Day	16% 10% 3 9% 5% 5% 4 4 6% 6% 32%	4138
	11th to 20th	Day	18% 8% 2 6% 4 4 5% 4 6% 8% 33%	4606
	21st to end	Day	22% 9% 3 6% 4 4 4 4 5% 8% 32%	5185
June	1st to 10th	Day	21% 9% 3 7% 5% 4 4 4 4 6% 33%	2850
	11th to 20th	Day	19% 7% 2 6% 4 4 4 4 5% 8% 36%	2850
	21st to end	Day	21% 8% 3 6% 5% 5% 5% 4 6% 8% 31%	2850
July	1st to 10th	Day	15% 9% 2 7% 4 4 5% 4 6% 7% 37%	4760
	11th to 20th	Day	13% 5% 3 7% 5% 4 5% 5% 7% 8% 38%	4760
	21st to end	Day	12% 5% 2 5% 4 4 5% 3 6% 9% 44%	4983
August	1st to 10th	Day	13% 6% 2 6% 4 5% 5% 5% 7% 10% 38%	4208
	11th to 20th	Day	18% 6% 2 7% 4 4 5% 5% 7% 8% 34%	4045
	21st to end	Day	15% 6% 2 5% 4 4 5% 4 6% 9% 41%	4532
September	1st to 10th	Day	20% 7% 2 5% 3 3 3 4 5% 7% 42%	2314
	11th to 20th	Day	22% 6% 2 5% 3 3 4 3 3 5% 44%	2090
	21st to end	Day	20% 8% 3 6% 4 4 4 3 4 7% 38%	2090
October	1st to 10th	Day	20% 8% 3 7% 4 4 5% 3 5% 6% 36%	1957
	11th to 20th	Day	26% 10% 3 6% 4 3 4 4 5% 6% 29%	1867
	21st to end	Day	26% 15% 3 6% 4 4 3 3 5% 7% 25%	1881
November	1st to 10th	Day	21% 14% 4 9% 6% 4 4 3 4 6% 25%	1641
	11th to 20th	Day	23% 17% 6% 12% 6% 3 4 3 4 4 18%	1600
	21st to end	Day	21% 19% 7% 14% 6% 5% 4 3 4 4 14%	1514
December	1st to 10th	Day	14% 22% 7% 19% 12% 5% 4 2 3 3 9%	2280
	11th to 20th	Day	16% 15% 6% 19% 11% 7% 5% 2 4 3 12%	2618
	21st to end	Day	13% 16% 5% 16% 12% 8% 6% 3 4 4 12%	3476
January	1st to 10th	Night	16% 29% 8% 16% 10% 6% 3 2 3 2 5%	6808
	11th to 20th	Night	10% 18% 8% 21% 12% 6% 4 3 4 4 10%	6611
	21st to end	Night	5% 11% 5% 13% 10% 11% 13% 6% 5% 5% 16%	6996
February	1st to 10th	Night	9% 14% 5% 12% 9% 8% 7% 5% 5% 6% 21%	2668
	11th to 20th	Night	13% 19% 7% 11% 7% 6% 6% 4 4 5% 19%	2533
	21st to end	Night	11% 17% 4 10% 8% 7% 5% 4 4 6% 25%	2028
March	1st to 10th	Night	16% 17% 4 9% 7% 7% 7% 4 4 4 21%	5275
	11th to 20th	Night	20% 19% 5% 11% 7% 5% 5% 3 5% 4 17%	4979
	21st to end	Night	25% 18% 4 7% 7% 4 3 2 3 4 22%	5466
April	1st to 10th	Night	22% 14% 4 11% 5% 4 3 3 3 5% 25%	1962
	11th to 20th	Night	21% 10% 2 6% 4 4 4 4 6% 6% 32%	1695
	21st to end	Night	26% 10% 4 5% 3 4 3 2 5% 5% 35%	1710
May	1st to 10th	Night	21% 10% 3 8% 4 4 4 3 6% 8% 28%	2803
	11th to 20th	Night	18% 8% 3 8% 5% 4 4 4 6% 8% 31%	2326
	21st to end	Night	21% 10% 4 9% 6% 4 5% 4 6% 6% 23%	2401
June	1st to 10th	Night	23% 9% 4 6% 5% 4 4 4 5% 7% 30%	1330
	11th to 20th	Night	20% 7% 2 7% 5% 4 4 4 7% 7% 33%	1330
	21st to end	Night	21% 11% 3 7% 5% 4 4 4 6% 5% 29%	1330
July	1st to 10th	Night	18% 7% 4 8% 5% 4 5% 4 6% 6% 33%	2210
	11th to 20th	Night	14% 7% 3 8% 5% 5% 5% 6% 7% 9% 32%	2210
	21st to end	Night	13% 6% 2 5% 4 4 5% 4 7% 8% 40%	2571
August	1st to 10th	Night	18% 8% 3 8% 6% 6% 6% 5% 7% 9% 25%	2689
	11th to 20th	Night	15% 6% 3 8% 7% 5% 6% 5% 7% 8% 29%	2782
	21st to end	Night	19% 5% 2 5% 3 4 5% 3 6% 6% 42%	3124
September	1st to 10th	Night	20% 6% 2 7% 5% 4 5% 3 5% 6% 37%	1863
	11th to 20th	Night	22% 7% 2 7% 3 3 4 3 4 6% 38%	2090
	21st to end	Night	20% 7% 2 5% 4 3 4 3 4 6% 43%	2090
October	1st to 10th	Night	22% 6% 3 6% 5% 4 4 3 5% 6% 37%	2223
	11th to 20th	Night	28% 11% 3 6% 5% 3 4 3 4 6% 27%	2310
	21st to end	Night	25% 13% 3 8% 4 4 4 3 5% 6% 25%	2717
November	1st to 10th	Night	23% 15% 5% 9% 4 4 4 3 4 6% 25%	2655
	11th to 20th	Night	22% 19% 6% 11% 4 3 3 4 3 5% 19%	2800
	21st to end	Night	20% 21% 6% 15% 7% 4 3 3 4 4 13%	2885
December	1st to 10th	Night	14% 21% 9% 22% 8% 5% 4 2 3 3 9%	4910
	11th to 20th	Night	17% 16% 5% 18% 12% 6% 4 3 3 3 11%	5591
	21st to end	Night	15% 17% 6% 15% 10% 7% 5% 4 5% 5% 12%	7502

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	86% 5% 6% 2 1	3158
	11th to 20th	Day	81% 5% 8% 5% 2	3309
	21st to end	Day	65% 8% 11% 11% 4	3960
February	1st to 10th	Day	64% 8% 10% 12% 5% 1	1730
	11th to 20th	Day	66% 7% 11% 11% 4	1761
	21st to end	Day	57% 7% 10% 19% 7%	1600
March	1st to 10th	Day	65% 6% 12% 12% 4	4568
	11th to 20th	Day	65% 8% 9% 13% 4	4980
	21st to end	Day	65% 4 7% 16% 7% 2	5466
April	1st to 10th	Day	58% 6% 11% 14% 10% 1	2435
	11th to 20th	Day	50% 7% 11% 20% 11% 1	2442
	21st to end	Day	52% 6% 8% 20% 12% 2	2470
May	1st to 10th	Day	51% 9% 10% 20% 8% 1	4152
	11th to 20th	Day	47% 10% 12% 20% 10% 1	4610
	21st to end	Day	49% 7% 11% 22% 10% 1	5185
June	1st to 10th	Day	51% 7% 10% 19% 11% 2	2850
	11th to 20th	Day	46% 8% 12% 19% 13% 1	2850
	21st to end	Day	51% 9% 13% 17% 10% 1	2850
July	1st to 10th	Day	45% 7% 13% 26% 9%	4685
	11th to 20th	Day	41% 8% 21% 23% 6%	4679
	21st to end	Day	36% 8% 19% 28% 9%	4824
August	1st to 10th	Day	40% 9% 20% 25% 5%	4194
	11th to 20th	Day	46% 9% 23% 17% 5%	4084
	21st to end	Day	40% 8% 20% 23% 10%	4532
September	1st to 10th	Day	42% 7% 17% 25% 9%	2314
	11th to 20th	Day	43% 7% 15% 26% 9%	2090
	21st to end	Day	47% 6% 14% 24% 8%	2090
October	1st to 10th	Day	52% 7% 15% 19% 6%	3256
	11th to 20th	Day	55% 6% 13% 23% 3	3083
	21st to end	Day	54% 6% 17% 16% 6%	3081
November	1st to 10th	Day	62% 6% 13% 14% 5%	1641
	11th to 20th	Day	70% 7% 9% 11% 3	1600
	21st to end	Day	74% 7% 10% 6% 3	1514
December	1st to 10th	Day	80% 5% 8% 6%	2280
	11th to 20th	Day	77% 6% 6% 9% 2	2618
	21st to end	Day	72% 10% 8% 8% 3	3476
January	1st to 10th	Night	86% 5% 4 3	6808
	11th to 20th	Night	77% 5% 9% 6% 3	6659
	21st to end	Night	68% 7% 9% 10% 5%	6996
February	1st to 10th	Night	64% 8% 9% 11% 7% 1	2668
	11th to 20th	Night	67% 6% 10% 12% 5%	2536
	21st to end	Night	60% 7% 11% 15% 7%	2028
March	1st to 10th	Night	64% 5% 11% 13% 7%	5284
	11th to 20th	Night	68% 6% 10% 10% 5%	4980
	21st to end	Night	67% 3 7% 14% 8% 1	5466
April	1st to 10th	Night	63% 4 9% 11% 12% 1	1962
	11th to 20th	Night	52% 6% 9% 18% 14% 1	1695
	21st to end	Night	52% 5% 7% 20% 14% 2	1710
May	1st to 10th	Night	51% 9% 15% 14% 11% 1	2809
	11th to 20th	Night	48% 7% 13% 20% 11% 1	2327
	21st to end	Night	55% 8% 10% 18% 7% 1	2402
June	1st to 10th	Night	53% 7% 9% 18% 11% 1	1330
	11th to 20th	Night	48% 5% 14% 19% 12% 2	1330
	21st to end	Night	56% 7% 9% 17% 11%	1330
July	1st to 10th	Night	49% 7% 13% 25% 7%	2175
	11th to 20th	Night	44% 9% 19% 22% 5%	2168
	21st to end	Night	38% 9% 20% 21% 11%	2489
August	1st to 10th	Night	52% 10% 17% 18% 4	2679
	11th to 20th	Night	48% 10% 23% 14% 5%	2809
	21st to end	Night	42% 8% 14% 23% 13%	3124
September	1st to 10th	Night	46% 6% 13% 24% 10% 1	1863
	11th to 20th	Night	48% 6% 14% 23% 9% 1	2090
	21st to end	Night	43% 6% 13% 24% 13%	2090
October	1st to 10th	Night	49% 6% 12% 26% 7% 1	3704
	11th to 20th	Night	55% 5% 13% 23% 4	3833
	21st to end	Night	57% 6% 14% 18% 4	4467
November	1st to 10th	Night	61% 6% 15% 13% 5% 1	2655
	11th to 20th	Night	69% 6% 11% 11% 4	2800
	21st to end	Night	75% 7% 8% 6% 3 1	2885
December	1st to 10th	Night	79% 6% 9% 5% 1	4910
	11th to 20th	Night	78% 5% 7% 8% 2	5592
	21st to end	Night	70% 9% 10% 8% 3	7502

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	30% 19% 32% 16% 3 1	200
	11th to 20th	Day	23% 25% 27% 13% 12% 2	200
	21st to end	Day	17% 23% 35% 17% 6% 1	220
February	1st to 10th	Day	18% 24% 34% 18% 5% 2	330
	11th to 20th	Day	18% 23% 39% 14% 5%	396
	21st to end	Day	18% 21% 37% 17% 6% 1	389
March	1st to 10th	Day	24% 16% 33% 21% 6% 1	500
	11th to 20th	Day	24% 19% 31% 17% 8% 1	500
	21st to end	Day	27% 20% 30% 16% 7% 1	550
April	1st to 10th	Day	27% 22% 29% 17% 4 1	500
	11th to 20th	Day	24% 14% 37% 18% 5% 1	452
	21st to end	Day	28% 19% 28% 17% 6% 2	460
May	1st to 10th	Day	27% 16% 30% 18% 7% 1	482
	11th to 20th	Day	23% 12% 29% 23% 12% 2	674
	21st to end	Day	27% 16% 28% 21% 8% 1	735
June	1st to 10th	Day	23% 12% 29% 27% 8% 1	680
	11th to 20th	Day	21% 12% 31% 24% 10% 1	680
	21st to end	Day	23% 9% 29% 29% 9% 1	680
July	1st to 10th	Day	17% 11% 32% 27% 12% 2	670
	11th to 20th	Day	16% 9% 28% 32% 13% 1	668
	21st to end	Day	18% 6% 26% 34% 14% 2	636
August	1st to 10th	Day	18% 7% 25% 33% 13% 2	486
	11th to 20th	Day	18% 7% 27% 30% 17% 2	479
	21st to end	Day	19% 9% 25% 27% 15% 4	539
September	1st to 10th	Day	22% 13% 25% 25% 12% 3	490
	11th to 20th	Day	24% 11% 30% 21% 12% 2	490
	21st to end	Day	22% 15% 29% 20% 12% 3	490
October	1st to 10th	Day	21% 16% 31% 20% 9% 2	420
	11th to 20th	Day	34% 17% 21% 18% 8% 2	390
	21st to end	Day	33% 20% 23% 15% 8% 1	429
November	1st to 10th	Day	30% 25% 28% 16% 2	395
	11th to 20th	Day	34% 21% 25% 16% 5% 1	400
	21st to end	Day	30% 26% 25% 15% 4	314
December	1st to 10th	Day	29% 22% 27% 15% 8% 1	200
	11th to 20th	Day	22% 30% 33% 14% 3	200
	21st to end	Day	22% 24% 29% 23% 3	220
January	1st to 10th	Night	26% 20% 33% 16% 4	900
	11th to 20th	Night	23% 23% 29% 18% 6% 1	865
	21st to end	Night	15% 22% 32% 24% 7% 1	880
February	1st to 10th	Night	15% 23% 34% 22% 6% 1	800
	11th to 20th	Night	25% 16% 33% 21% 5% 1	783
	21st to end	Night	18% 15% 36% 22% 7% 1	660
March	1st to 10th	Night	23% 14% 33% 23% 6% 1	800
	11th to 20th	Night	24% 20% 27% 19% 8% 1	800
	21st to end	Night	25% 16% 29% 22% 7% 1	880
April	1st to 10th	Night	29% 18% 28% 19% 6%	719
	11th to 20th	Night	26% 14% 25% 24% 10% 1	567
	21st to end	Night	31% 14% 24% 22% 8% 1	570
May	1st to 10th	Night	28% 11% 25% 28% 8% 1	570
	11th to 20th	Night	21% 8% 28% 29% 14% 1	460
	21st to end	Night	26% 9% 31% 25% 9%	411
June	1st to 10th	Night	26% 8% 22% 37% 8%	380
	11th to 20th	Night	20% 8% 27% 29% 14% 1	380
	21st to end	Night	22% 6% 29% 31% 11% 1	380
July	1st to 10th	Night	21% 7% 25% 35% 10% 2	370
	11th to 20th	Night	17% 6% 28% 36% 12% 2	368
	21st to end	Night	17% 6% 24% 39% 13% 1	416
August	1st to 10th	Night	18% 6% 23% 33% 18% 1	483
	11th to 20th	Night	17% 5% 22% 38% 17% 2	562
	21st to end	Night	18% 6% 22% 35% 17% 2	627
September	1st to 10th	Night	23% 9% 28% 28% 11% 1	621
	11th to 20th	Night	25% 9% 26% 26% 13% 2	760
	21st to end	Night	22% 11% 29% 26% 11% 1	760
October	1st to 10th	Night	24% 14% 29% 23% 9% 1	760
	11th to 20th	Night	34% 11% 24% 20% 10% 1	760
	21st to end	Night	32% 18% 24% 20% 6% 1	836
November	1st to 10th	Night	31% 19% 29% 16% 4 1	840
	11th to 20th	Night	30% 20% 27% 18% 4 1	900
	21st to end	Night	29% 22% 27% 17% 5% 1	900
December	1st to 10th	Night	29% 19% 30% 16% 5% 1	900
	11th to 20th	Night	28% 24% 28% 16% 4	900
	21st to end	Night	25% 23% 26% 20% 4 1	990

Page generated at 2025-04-08 09:17:24. Version ac07

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