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 2024-02-20.

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 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	18% 10% 4 7% 7% 4 5% 5% 5% 7% 29%	77825
	Night	18% 13% 5% 9% 8% 4 5% 4 5% 5% 23%	81383
Transparency	Day	38% 37% 8% 12% 5%	77513
	Night	43% 36% 7% 9% 4	81230
Seeing	Day	23% 15% 30% 22% 9% 1	15019
	Night	24% 15% 28% 23% 8% 1	23062

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	15% 16% 8% 15% 14% 13% 4 3 3 4 5%	2207
	11th to 20th	Day	12% 18% 8% 13% 18% 6% 6% 5% 4 3 7%	2307
	21st to end	Day	6% 10% 4 11% 12% 8% 9% 7% 5% 7% 21%	2772
February	1st to 10th	Day	10% 13% 4 11% 10% 7% 8% 6% 6% 6% 20%	1643
	11th to 20th	Day	12% 15% 6% 12% 9% 6% 6% 6% 4 5% 20%	1654
	21st to end	Day	10% 13% 5% 8% 7% 5% 6% 6% 5% 8% 27%	1435
March	1st to 10th	Day	14% 14% 6% 7% 6% 4 6% 6% 4 8% 26%	1829
	11th to 20th	Day	15% 15% 6% 8% 8% 4 6% 4 5% 5% 24%	1980
	21st to end	Day	15% 15% 5% 7% 6% 3 3 4 5% 5% 33%	2178
April	1st to 10th	Day	21% 12% 4 6% 7% 4 4 4 5% 6% 26%	2191
	11th to 20th	Day	17% 10% 4 6% 4 3 4 4 5% 8% 35%	2312
	21st to end	Day	21% 10% 3 7% 4 4 4 4 4 6% 34%	2340
May	1st to 10th	Day	25% 9% 3 6% 5% 2 3 4 4 6% 32%	2358
	11th to 20th	Day	21% 7% 2 5% 4 3 4 5% 5% 7% 36%	2588
	21st to end	Day	24% 6% 2 4 5% 3 3 5% 5% 7% 35%	2919
June	1st to 10th	Day	22% 8% 3 6% 6% 3 4 5% 4 7% 33%	2700
	11th to 20th	Day	19% 6% 2 5% 5% 3 4 5% 5% 8% 37%	2700
	21st to end	Day	21% 7% 3 5% 5% 3 6% 4 6% 8% 31%	2700
July	1st to 10th	Day	15% 7% 3 6% 5% 3 5% 5% 7% 8% 34%	2700
	11th to 20th	Day	15% 5% 3 5% 5% 3 5% 5% 7% 8% 39%	2700
	21st to end	Day	15% 6% 3 6% 5% 4 6% 4 6% 9% 37%	2843
August	1st to 10th	Day	16% 6% 2 6% 5% 4 5% 6% 7% 9% 35%	2388
	11th to 20th	Day	17% 5% 3 5% 4 2 5% 5% 6% 8% 40%	2304
	21st to end	Day	17% 5% 3 5% 5% 4 5% 5% 6% 9% 38%	2574
September	1st to 10th	Day	20% 7% 3 4 4 3 3 4 5% 6% 42%	2193
	11th to 20th	Day	24% 6% 2 5% 3 2 4 3 3 5% 43%	1980
	21st to end	Day	20% 7% 3 5% 4 2 5% 4 4 6% 39%	1980
October	1st to 10th	Day	20% 7% 3 5% 5% 3 5% 4 5% 6% 37%	1854
	11th to 20th	Day	27% 10% 3 5% 5% 2 4 5% 5% 6% 29%	1769
	21st to end	Day	27% 14% 4 5% 5% 3 4 3 5% 7% 24%	1782
November	1st to 10th	Day	21% 13% 5% 8% 6% 3 4 4 4 6% 25%	1557
	11th to 20th	Day	21% 15% 7% 12% 7% 2 4 5% 4 5% 18%	1520
	21st to end	Day	21% 17% 7% 13% 8% 3 5% 5% 4 4 14%	1439
December	1st to 10th	Day	19% 15% 7% 14% 14% 6% 5% 4 4 4 9%	1330
	11th to 20th	Day	17% 14% 6% 14% 14% 7% 7% 4 4 3 10%	1668
	21st to end	Day	15% 16% 6% 12% 11% 5% 5% 5% 4 5% 15%	2431
January	1st to 10th	Night	11% 22% 9% 16% 17% 7% 5% 3 3 2 6%	4748
	11th to 20th	Night	13% 17% 7% 14% 15% 5% 5% 5% 4 4 11%	4655
	21st to end	Night	7% 14% 7% 12% 9% 6% 9% 6% 4 6% 20%	4884
February	1st to 10th	Night	9% 14% 6% 11% 9% 6% 7% 6% 5% 6% 22%	2535
	11th to 20th	Night	13% 17% 7% 10% 8% 5% 6% 5% 4 5% 19%	2397
	21st to end	Night	11% 15% 6% 9% 9% 6% 6% 5% 4 6% 24%	1819
March	1st to 10th	Night	14% 14% 7% 8% 7% 4 5% 5% 4 4 27%	2117
	11th to 20th	Night	17% 16% 5% 10% 7% 4 4 4 4 4 25%	1979
	21st to end	Night	18% 14% 5% 7% 6% 4 4 4 3 5% 30%	2178
April	1st to 10th	Night	23% 13% 4 10% 6% 4 3 4 4 6% 24%	1767
	11th to 20th	Night	22% 9% 3 6% 4 3 4 5% 5% 6% 33%	1598
	21st to end	Night	27% 9% 3 5% 4 2 4 3 5% 5% 35%	1620
May	1st to 10th	Night	25% 11% 4 7% 4 3 4 3 5% 6% 27%	1602
	11th to 20th	Night	20% 8% 4 7% 6% 3 5% 5% 4 6% 33%	1320
	21st to end	Night	23% 7% 3 7% 6% 3 5% 6% 7% 6% 27%	1356
June	1st to 10th	Night	23% 8% 4 6% 6% 3 5% 5% 5% 7% 29%	1260
	11th to 20th	Night	21% 7% 2 5% 7% 3 4 5% 7% 7% 33%	1260
	21st to end	Night	21% 11% 3 6% 6% 3 5% 4 6% 5% 30%	1260
July	1st to 10th	Night	19% 6% 4 8% 5% 3 5% 6% 6% 7% 30%	1260
	11th to 20th	Night	15% 6% 3 7% 6% 3 6% 5% 7% 10% 34%	1260
	21st to end	Night	17% 7% 3 5% 6% 4 6% 6% 8% 9% 30%	1471
August	1st to 10th	Night	16% 7% 3 6% 6% 4 6% 6% 7% 9% 31%	1531
	11th to 20th	Night	17% 5% 3 6% 6% 3 6% 5% 7% 9% 33%	1596
	21st to end	Night	18% 6% 2 5% 5% 3 5% 5% 6% 7% 37%	1782
September	1st to 10th	Night	20% 6% 3 6% 6% 3 5% 5% 5% 6% 37%	1764
	11th to 20th	Night	23% 6% 2 5% 5% 3 3 4 4 6% 38%	1980
	21st to end	Night	20% 6% 2 4 5% 2 3 4 4 6% 44%	1980
October	1st to 10th	Night	22% 5% 3 5% 5% 3 4 4 5% 6% 37%	2106
	11th to 20th	Night	28% 11% 3 6% 5% 3 4 4 4 6% 27%	2188
	21st to end	Night	26% 12% 3 7% 5% 3 4 4 5% 6% 25%	2574
November	1st to 10th	Night	23% 14% 5% 8% 5% 3 4 4 4 6% 24%	2519
	11th to 20th	Night	22% 17% 7% 10% 5% 2 4 5% 3 6% 18%	2660
	21st to end	Night	19% 19% 7% 14% 8% 3 4 4 4 4 14%	2740
December	1st to 10th	Night	21% 17% 9% 16% 10% 4 4 3 4 3 10%	2850
	11th to 20th	Night	18% 17% 6% 15% 14% 6% 5% 3 3 4 10%	3531
	21st to end	Night	15% 18% 6% 11% 10% 4 5% 4 5% 6% 15%	5236

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	69% 26% 4 1	2208
	11th to 20th	Day	65% 27% 3 3 2	2307
	21st to end	Day	48% 27% 8% 14% 3	2772
February	1st to 10th	Day	43% 37% 8% 9% 4	1643
	11th to 20th	Day	49% 36% 6% 6% 2	1662
	21st to end	Day	37% 37% 9% 13% 4	1435
March	1st to 10th	Day	41% 38% 8% 10% 2	1833
	11th to 20th	Day	41% 37% 7% 10% 5%	1980
	21st to end	Day	37% 36% 7% 12% 8%	2178
April	1st to 10th	Day	40% 38% 8% 9% 5% 1	2191
	11th to 20th	Day	32% 37% 8% 15% 8% 1	2312
	21st to end	Day	32% 37% 7% 15% 9% 1	2340
May	1st to 10th	Day	36% 37% 6% 11% 7% 1	2358
	11th to 20th	Day	30% 38% 7% 15% 9% 1	2592
	21st to end	Day	32% 38% 7% 14% 8%	2919
June	1st to 10th	Day	34% 39% 7% 11% 7% 2	2700
	11th to 20th	Day	29% 38% 9% 13% 9% 1	2700
	21st to end	Day	38% 39% 8% 10% 5%	2700
July	1st to 10th	Day	29% 39% 12% 15% 5%	2625
	11th to 20th	Day	29% 40% 11% 14% 5%	2619
	21st to end	Day	32% 41% 10% 13% 4	2684
August	1st to 10th	Day	31% 40% 11% 14% 3	2374
	11th to 20th	Day	27% 39% 14% 16% 3	2304
	21st to end	Day	30% 39% 13% 15% 4	2574
September	1st to 10th	Day	29% 38% 10% 18% 5%	2193
	11th to 20th	Day	29% 38% 9% 18% 7%	1980
	21st to end	Day	33% 38% 8% 17% 4	1980
October	1st to 10th	Day	35% 38% 11% 11% 4	1854
	11th to 20th	Day	38% 39% 9% 10% 4	1769
	21st to end	Day	39% 39% 6% 11% 4 1	1782
November	1st to 10th	Day	36% 41% 10% 10% 4	1557
	11th to 20th	Day	43% 41% 8% 7% 2	1520
	21st to end	Day	47% 41% 5% 5% 2	1439
December	1st to 10th	Day	53% 40% 4 4	1330
	11th to 20th	Day	55% 33% 4 6% 2	1668
	21st to end	Day	52% 30% 7% 10% 1	2431
January	1st to 10th	Night	68% 27% 3 2	4748
	11th to 20th	Night	58% 29% 4 5% 3	4655
	21st to end	Night	50% 27% 7% 10% 6%	4884
February	1st to 10th	Night	43% 36% 9% 7% 5% 1	2535
	11th to 20th	Night	47% 36% 6% 7% 3	2400
	21st to end	Night	42% 37% 7% 11% 3	1819
March	1st to 10th	Night	44% 37% 5% 11% 3	2126
	11th to 20th	Night	41% 37% 6% 11% 5%	1980
	21st to end	Night	40% 36% 6% 11% 7%	2178
April	1st to 10th	Night	43% 36% 6% 6% 7% 1	1767
	11th to 20th	Night	33% 38% 5% 14% 10% 1	1598
	21st to end	Night	31% 36% 6% 14% 10% 2	1620
May	1st to 10th	Night	39% 37% 5% 11% 8% 1	1602
	11th to 20th	Night	31% 38% 7% 15% 9%	1321
	21st to end	Night	37% 39% 5% 11% 6% 1	1357
June	1st to 10th	Night	37% 37% 8% 10% 8% 1	1260
	11th to 20th	Night	32% 38% 8% 12% 8% 1	1260
	21st to end	Night	40% 38% 5% 9% 7%	1260
July	1st to 10th	Night	34% 38% 9% 14% 5%	1225
	11th to 20th	Night	31% 41% 9% 13% 6%	1218
	21st to end	Night	32% 42% 11% 12% 4	1389
August	1st to 10th	Night	33% 40% 10% 14% 4	1521
	11th to 20th	Night	32% 40% 13% 12% 4	1596
	21st to end	Night	32% 39% 7% 17% 4	1782
September	1st to 10th	Night	31% 38% 9% 16% 6%	1764
	11th to 20th	Night	31% 37% 9% 17% 6% 1	1980
	21st to end	Night	29% 38% 9% 15% 8%	1980
October	1st to 10th	Night	33% 38% 10% 13% 5% 1	2106
	11th to 20th	Night	41% 37% 9% 10% 3	2188
	21st to end	Night	38% 39% 8% 10% 4 1	2574
November	1st to 10th	Night	36% 43% 10% 9% 3	2519
	11th to 20th	Night	42% 40% 7% 8% 2	2660
	21st to end	Night	46% 41% 6% 4 1 1	2740
December	1st to 10th	Night	53% 40% 4 2 1	2850
	11th to 20th	Night	56% 33% 4 5% 1	3532
	21st to end	Night	51% 30% 10% 6% 2 1	5236

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	29% 17% 34% 16% 3 1	180
	11th to 20th	Day	24% 26% 28% 14% 7% 1	180
	21st to end	Day	19% 22% 34% 18% 5% 2	198
February	1st to 10th	Day	19% 23% 33% 18% 6% 2	303
	11th to 20th	Day	17% 24% 40% 14% 4	363
	21st to end	Day	19% 19% 39% 16% 7% 1	326
March	1st to 10th	Day	23% 17% 32% 21% 7% 1	420
	11th to 20th	Day	25% 19% 30% 18% 8% 1	420
	21st to end	Day	24% 20% 31% 16% 7% 1	462
April	1st to 10th	Day	26% 21% 30% 17% 4 1	420
	11th to 20th	Day	25% 13% 37% 18% 5% 1	412
	21st to end	Day	27% 18% 29% 18% 6% 2	420
May	1st to 10th	Day	28% 15% 32% 17% 7% 1	441
	11th to 20th	Day	24% 12% 30% 22% 11% 1	624
	21st to end	Day	27% 16% 29% 19% 8% 1	680
June	1st to 10th	Day	24% 12% 30% 27% 7% 1	630
	11th to 20th	Day	22% 12% 32% 24% 10% 1	630
	21st to end	Day	23% 9% 28% 29% 10% 1	630
July	1st to 10th	Day	17% 11% 33% 25% 12% 2	620
	11th to 20th	Day	17% 9% 28% 31% 14% 1	618
	21st to end	Day	19% 6% 27% 33% 14% 2	587
August	1st to 10th	Day	18% 8% 25% 32% 14% 2	446
	11th to 20th	Day	17% 7% 27% 30% 17% 2	439
	21st to end	Day	19% 9% 26% 26% 15% 4	495
September	1st to 10th	Day	24% 12% 24% 25% 12% 3	450
	11th to 20th	Day	26% 12% 31% 20% 10% 2	450
	21st to end	Day	22% 16% 30% 20% 11% 2	450
October	1st to 10th	Day	21% 17% 32% 19% 9% 2	387
	11th to 20th	Day	34% 16% 21% 19% 8% 2	360
	21st to end	Day	33% 20% 23% 14% 8% 1	396
November	1st to 10th	Day	30% 25% 28% 16% 2	365
	11th to 20th	Day	31% 22% 26% 16% 5% 1	370
	21st to end	Day	28% 26% 27% 14% 5%	289
December	1st to 10th	Day	27% 22% 27% 16% 8% 1	180
	11th to 20th	Day	21% 29% 34% 13% 2	180
	21st to end	Day	22% 25% 31% 21% 1	198
January	1st to 10th	Night	24% 21% 34% 17% 4	850
	11th to 20th	Night	25% 23% 30% 18% 4	819
	21st to end	Night	15% 21% 31% 25% 7% 1	836
February	1st to 10th	Night	15% 23% 33% 22% 6% 1	760
	11th to 20th	Night	24% 16% 33% 20% 6% 1	742
	21st to end	Night	18% 15% 36% 23% 7% 1	592
March	1st to 10th	Night	23% 13% 33% 23% 7% 1	720
	11th to 20th	Night	24% 20% 28% 19% 8% 1	720
	21st to end	Night	23% 16% 29% 23% 8% 1	792
April	1st to 10th	Night	29% 17% 29% 18% 6%	648
	11th to 20th	Night	26% 14% 26% 24% 10% 1	534
	21st to end	Night	31% 13% 24% 22% 9% 1	540
May	1st to 10th	Night	29% 11% 24% 28% 8% 1	540
	11th to 20th	Night	22% 8% 29% 28% 13%	436
	21st to end	Night	27% 8% 32% 24% 9% 1	389
June	1st to 10th	Night	26% 8% 22% 37% 7%	360
	11th to 20th	Night	21% 9% 25% 29% 14% 1	360
	21st to end	Night	22% 6% 29% 30% 12% 1	360
July	1st to 10th	Night	21% 7% 26% 34% 10% 2	350
	11th to 20th	Night	17% 6% 28% 36% 12% 2	348
	21st to end	Night	18% 6% 24% 38% 13% 2	394
August	1st to 10th	Night	18% 6% 22% 34% 19% 2	457
	11th to 20th	Night	17% 5% 22% 36% 17% 2	532
	21st to end	Night	18% 6% 23% 35% 15% 2	594
September	1st to 10th	Night	22% 10% 27% 28% 12% 1	588
	11th to 20th	Night	26% 9% 27% 25% 12% 2	720
	21st to end	Night	22% 11% 30% 27% 9% 1	720
October	1st to 10th	Night	24% 14% 29% 23% 8% 1	720
	11th to 20th	Night	34% 11% 24% 20% 11% 1	720
	21st to end	Night	33% 17% 24% 19% 6% 1	792
November	1st to 10th	Night	30% 19% 29% 16% 5% 1	794
	11th to 20th	Night	29% 20% 27% 18% 4 2	850
	21st to end	Night	27% 22% 27% 17% 5% 1	850
December	1st to 10th	Night	30% 20% 29% 16% 5% 1	850
	11th to 20th	Night	28% 24% 28% 16% 4	850
	21st to end	Night	25% 23% 26% 20% 4 1	935

Page generated at 2024-02-17 06:28:39. Version ac07

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