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 2024-10-24.

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% 10% 3 8% 6% 5% 5% 4 5% 7% 30%	101650
	Night	18% 13% 4 10% 7% 5% 5% 3 5% 6% 24%	97207
Transparency	Day	53% 8% 13% 18% 7% 1	101391
	Night	60% 7% 11% 14% 7%	97087
Seeing	Day	23% 15% 29% 22% 9% 1	16060
	Night	24% 15% 28% 23% 8% 1	23811

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% 17% 8% 17% 12% 14% 3 2 3 4 5%	2207
	11th to 20th	Day	12% 19% 8% 15% 16% 7% 6% 4 4 3 7%	2307
	21st to end	Day	6% 11% 4 13% 11% 10% 7% 5% 5% 7% 21%	2772
February	1st to 10th	Day	10% 14% 3 12% 10% 8% 7% 5% 6% 6% 20%	1643
	11th to 20th	Day	11% 15% 6% 13% 8% 7% 6% 5% 4 5% 20%	1663
	21st to end	Day	10% 14% 4 9% 7% 7% 7% 4 5% 7% 27%	1522
March	1st to 10th	Day	13% 12% 4 8% 6% 7% 6% 4 5% 8% 27%	3176
	11th to 20th	Day	21% 20% 4 8% 5% 4 5% 4 5% 5% 19%	3480
	21st to end	Day	22% 16% 6% 8% 5% 3 3 3 3 4 28%	3816
April	1st to 10th	Day	20% 13% 3 7% 6% 5% 4 3 5% 6% 28%	2313
	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% 24%	1809
November	1st to 10th	Day	21% 14% 4 10% 6% 4 4 3 4 6% 25%	1557
	11th to 20th	Day	21% 16% 7% 13% 6% 3 5% 3 4 5% 18%	1520
	21st to end	Day	20% 18% 7% 14% 6% 5% 4 4 4 4 14%	1439
December	1st to 10th	Day	18% 17% 6% 15% 13% 7% 5% 3 4 4 9%	1330
	11th to 20th	Day	16% 15% 6% 16% 12% 9% 6% 3 4 3 10%	1668
	21st to end	Day	15% 17% 6% 14% 10% 6% 5% 4 4 5% 15%	2431
January	1st to 10th	Night	11% 22% 9% 19% 14% 8% 4 2 3 2 5%	4748
	11th to 20th	Night	13% 17% 7% 16% 13% 6% 5% 4 4 4 11%	4655
	21st to end	Night	7% 15% 6% 13% 8% 9% 8% 4 4 6% 20%	4884
February	1st to 10th	Night	9% 15% 5% 12% 8% 7% 7% 4 5% 6% 22%	2535
	11th to 20th	Night	13% 18% 7% 11% 7% 6% 6% 4 4 5% 19%	2403
	21st to end	Night	11% 16% 4 10% 8% 8% 5% 4 4 6% 25%	1930
March	1st to 10th	Night	12% 12% 4 10% 7% 6% 7% 4 5% 5% 28%	3663
	11th to 20th	Night	23% 22% 5% 10% 6% 4 3 3 4 4 16%	3479
	21st to end	Night	26% 17% 4 6% 7% 3 3 2 3 4 24%	3816
April	1st to 10th	Night	22% 14% 4 11% 5% 4 3 3 3 5% 26%	1864
	11th to 20th	Night	21% 10% 2 6% 4 4 4 4 6% 6% 32%	1688
	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	26% 13% 3 8% 4 4 4 3 5% 6% 25%	2614
November	1st to 10th	Night	23% 15% 5% 9% 4 4 4 3 4 6% 24%	2519
	11th to 20th	Night	22% 19% 6% 11% 4 3 3 4 3 6% 18%	2660
	21st to end	Night	19% 20% 6% 15% 7% 4 3 3 4 5% 14%	2740
December	1st to 10th	Night	20% 20% 7% 17% 9% 5% 3 2 4 3 10%	2850
	11th to 20th	Night	17% 18% 6% 17% 12% 7% 4 2 3 4 10%	3531
	21st to end	Night	15% 19% 5% 13% 8% 6% 4 3 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	85% 5% 6% 3 1	2208
	11th to 20th	Day	81% 5% 7% 5% 2	2307
	21st to end	Day	59% 9% 10% 15% 6%	2772
February	1st to 10th	Day	63% 8% 10% 13% 5% 1	1643
	11th to 20th	Day	66% 7% 11% 11% 5%	1671
	21st to end	Day	57% 7% 10% 18% 8%	1522
March	1st to 10th	Day	55% 8% 16% 17% 4	3180
	11th to 20th	Day	67% 8% 8% 12% 5%	3480
	21st to end	Day	63% 4 7% 16% 7% 2	3816
April	1st to 10th	Day	57% 6% 11% 14% 10% 1	2313
	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	49% 7% 16% 19% 9% 1	1957
	11th to 20th	Day	56% 8% 13% 16% 6%	1867
	21st to end	Day	61% 7% 11% 14% 6% 1	1809
November	1st to 10th	Day	62% 6% 13% 13% 5%	1557
	11th to 20th	Day	70% 8% 9% 11% 3	1520
	21st to end	Day	73% 7% 10% 6% 3	1439
December	1st to 10th	Day	79% 8% 7% 6% 1	1330
	11th to 20th	Day	79% 6% 4 8% 2	1668
	21st to end	Day	69% 11% 8% 8% 4	2431
January	1st to 10th	Night	84% 7% 5% 4 1	4748
	11th to 20th	Night	75% 6% 8% 7% 4	4655
	21st to end	Night	63% 7% 9% 13% 7% 1	4884
February	1st to 10th	Night	63% 8% 9% 11% 8% 1	2535
	11th to 20th	Night	67% 6% 10% 12% 5%	2406
	21st to end	Night	60% 7% 11% 15% 7%	1930
March	1st to 10th	Night	56% 7% 13% 17% 7%	3672
	11th to 20th	Night	72% 5% 8% 9% 4	3480
	21st to end	Night	66% 4 8% 14% 8% 1	3816
April	1st to 10th	Night	62% 4 9% 11% 13% 1	1864
	11th to 20th	Night	52% 6% 9% 18% 15% 1	1688
	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	48% 5% 14% 22% 10% 1	2223
	11th to 20th	Night	59% 6% 12% 17% 6%	2310
	21st to end	Night	59% 7% 14% 15% 5% 1	2614
November	1st to 10th	Night	61% 6% 15% 12% 5% 1	2519
	11th to 20th	Night	69% 6% 11% 11% 3	2660
	21st to end	Night	74% 7% 9% 6% 3 1	2740
December	1st to 10th	Night	81% 6% 7% 5% 2	2850
	11th to 20th	Night	80% 5% 6% 7% 1	3532
	21st to end	Night	68% 8% 11% 8% 4 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% 23% 40% 14% 4	366
	21st to end	Day	19% 20% 38% 16% 6% 1	359
March	1st to 10th	Day	23% 17% 33% 21% 6% 1	460
	11th to 20th	Day	25% 19% 29% 18% 8% 1	460
	21st to end	Day	26% 20% 30% 16% 7% 1	506
April	1st to 10th	Day	26% 21% 30% 18% 4 1	460
	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% 14% 8% 1	405
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% 34% 20% 6% 1	743
	21st to end	Night	18% 15% 37% 22% 7% 1	628
March	1st to 10th	Night	22% 14% 33% 23% 6% 1	760
	11th to 20th	Night	25% 20% 27% 19% 9% 1	760
	21st to end	Night	25% 16% 29% 22% 7% 1	836
April	1st to 10th	Night	28% 17% 29% 19% 6%	683
	11th to 20th	Night	26% 14% 25% 24% 10% 1	564
	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	33% 18% 24% 20% 6% 1	805
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 2024-10-21 02:20:02. Version ac07

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