Marten River Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Marten River Provincial Park clear sky chart from 2005-11-06 to 2024-11-08.

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 9% 5% 4 4 3 5% 6% 30%	101724
	Night	16% 13% 4 9% 5% 4 4 3 5% 6% 29%	97412
Transparency	Day	55% 3 11% 22% 9% 1	105274
	Night	57% 3 11% 20% 9% 1	101951
Seeing	Day	25% 13% 31% 21% 8% 2	15165
	Night	25% 11% 30% 25% 8% 1	24170

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% 23% 8% 13% 5% 5% 4 3 4 6% 16%	2208
	11th to 20th	Day	11% 17% 9% 16% 8% 6% 4 3 4 6% 17%	2251
	21st to end	Day	17% 21% 10% 12% 5% 5% 4 3 5% 4 14%	3124
February	1st to 10th	Day	9% 20% 6% 12% 9% 8% 5% 4 4 4 20%	1710
	11th to 20th	Day	12% 18% 6% 11% 8% 4 4 3 4 5% 24%	1663
	21st to end	Day	15% 17% 5% 12% 6% 6% 5% 3 4 5% 22%	1422
March	1st to 10th	Day	19% 17% 4 8% 5% 4 4 3 5% 6% 25%	3391
	11th to 20th	Day	11% 17% 5% 14% 7% 5% 4 3 4 5% 25%	3480
	21st to end	Day	11% 14% 5% 12% 6% 5% 4 2 4 4 32%	3815
April	1st to 10th	Day	20% 14% 3 8% 5% 4 4 3 4 7% 27%	2251
	11th to 20th	Day	22% 10% 4 7% 5% 3 4 3 4 5% 32%	2411
	21st to end	Day	22% 12% 3 7% 4 4 3 2 4 4 34%	2470
May	1st to 10th	Day	20% 10% 3 7% 5% 4 4 3 5% 6% 32%	4254
	11th to 20th	Day	16% 8% 3 7% 5% 5% 4 3 6% 7% 36%	4398
	21st to end	Day	20% 6% 2 6% 4 4 4 3 5% 7% 39%	4837
June	1st to 10th	Day	18% 10% 3 7% 5% 4 5% 3 5% 7% 32%	2849
	11th to 20th	Day	15% 6% 2 6% 5% 5% 5% 5% 6% 7% 37%	2850
	21st to end	Day	18% 8% 3 8% 5% 5% 5% 4 6% 7% 31%	2850
July	1st to 10th	Day	17% 8% 3 7% 6% 5% 5% 4 6% 8% 32%	4760
	11th to 20th	Day	14% 6% 3 6% 4 4 5% 4 7% 9% 38%	4760
	21st to end	Day	12% 6% 2 6% 4 4 4 4 5% 8% 45%	4772
August	1st to 10th	Day	12% 8% 3 6% 5% 5% 5% 5% 6% 10% 36%	4104
	11th to 20th	Day	20% 6% 2 5% 4 4 4 4 5% 8% 37%	4044
	21st to end	Day	12% 7% 3 7% 5% 5% 4 4 6% 8% 41%	4450
September	1st to 10th	Day	19% 7% 3 7% 4 4 4 3 5% 7% 37%	2280
	11th to 20th	Day	19% 6% 2 6% 5% 4 4 4 5% 8% 38%	2167
	21st to end	Day	23% 8% 3 7% 4 4 4 3 5% 6% 33%	2055
October	1st to 10th	Day	20% 11% 3 7% 4 5% 5% 3 5% 6% 32%	1900
	11th to 20th	Day	24% 15% 4 8% 5% 4 4 3 4 5% 23%	1900
	21st to end	Day	29% 17% 3 8% 5% 4 4 2 4 6% 19%	2033
November	1st to 10th	Day	21% 15% 4 9% 5% 4 4 3 4 6% 26%	1550
	11th to 20th	Day	18% 17% 5% 11% 6% 5% 5% 3 4 6% 19%	1520
	21st to end	Day	26% 21% 4 11% 6% 4 4 2 4 4 14%	1520
December	1st to 10th	Day	18% 21% 6% 13% 7% 5% 4 3 4 5% 15%	1520
	11th to 20th	Day	17% 19% 6% 12% 5% 3 3 3 5% 4 22%	1724
	21st to end	Day	18% 23% 10% 17% 6% 4 2 2 2 3 15%	2431
January	1st to 10th	Night	15% 19% 7% 14% 7% 5% 4 3 5% 5% 14%	4748
	11th to 20th	Night	12% 16% 6% 13% 7% 7% 7% 4 4 4 19%	4712
	21st to end	Night	13% 23% 9% 13% 7% 6% 5% 3 4 4 14%	4532
February	1st to 10th	Night	11% 16% 6% 13% 8% 6% 6% 3 5% 5% 22%	2470
	11th to 20th	Night	13% 17% 7% 11% 7% 6% 5% 3 4 4 23%	2403
	21st to end	Night	14% 19% 5% 10% 7% 6% 4 3 5% 5% 23%	2027
March	1st to 10th	Night	14% 15% 4 9% 5% 4 5% 3 4 6% 30%	3448
	11th to 20th	Night	13% 17% 7% 10% 5% 4 4 3 4 6% 26%	3479
	21st to end	Night	13% 11% 6% 9% 5% 5% 4 3 5% 6% 33%	3817
April	1st to 10th	Night	20% 15% 5% 7% 4 4 3 3 5% 5% 30%	1929
	11th to 20th	Night	20% 10% 3 8% 5% 4 4 4 4 5% 34%	1735
	21st to end	Night	21% 10% 3 7% 5% 4 5% 4 5% 6% 32%	1710
May	1st to 10th	Night	18% 10% 3 9% 5% 4 4 4 5% 5% 34%	2687
	11th to 20th	Night	15% 8% 3 7% 4 4 5% 3 6% 8% 38%	2495
	21st to end	Night	14% 8% 2 6% 5% 4 4 4 6% 7% 39%	2723
June	1st to 10th	Night	16% 9% 3 7% 5% 5% 4 4 5% 6% 37%	1330
	11th to 20th	Night	16% 7% 2 6% 4 4 3 3 5% 8% 42%	1330
	21st to end	Night	15% 7% 3 7% 5% 4 5% 4 5% 8% 36%	1330
July	1st to 10th	Night	16% 6% 2 6% 5% 4 4 4 6% 8% 40%	2210
	11th to 20th	Night	15% 7% 3 6% 4 5% 4 3 6% 8% 41%	2210
	21st to end	Night	12% 6% 2 6% 4 3 3 3 6% 9% 47%	2777
August	1st to 10th	Night	13% 4 2 7% 5% 4 5% 5% 6% 7% 41%	2825
	11th to 20th	Night	14% 8% 3 6% 4 4 4 3 5% 7% 42%	2785
	21st to end	Night	16% 6% 2 6% 3 3 4 3 4 7% 46%	3174
September	1st to 10th	Night	16% 6% 2 5% 3 3 4 3 5% 7% 46%	1900
	11th to 20th	Night	16% 8% 2 5% 2 3 3 3 4 6% 48%	2009
	21st to end	Night	19% 8% 2 6% 4 3 3 3 5% 7% 40%	2124
October	1st to 10th	Night	19% 10% 2 7% 4 4 4 3 5% 5% 35%	2280
	11th to 20th	Night	26% 13% 3 7% 5% 4 4 3 4 6% 26%	2280
	21st to end	Night	25% 16% 4 8% 4 4 4 2 4 5% 23%	2561
November	1st to 10th	Night	21% 11% 3 8% 4 4 5% 3 5% 6% 29%	2687
	11th to 20th	Night	19% 17% 4 10% 6% 5% 3 3 4 6% 21%	2660
	21st to end	Night	22% 19% 4 11% 7% 4 4 3 5% 4 17%	2660
December	1st to 10th	Night	19% 22% 6% 12% 6% 5% 3 3 4 5% 16%	2660
	11th to 20th	Night	18% 20% 5% 10% 5% 5% 4 3 6% 6% 17%	3469
	21st to end	Night	19% 22% 9% 16% 6% 3 3 2 3 3 14%	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	73% 2 13% 10% 2	2209
	11th to 20th	Day	71% 1 9% 13% 5% 1	2251
	21st to end	Day	74% 2 7% 12% 5%	3124
February	1st to 10th	Day	68% 3 8% 14% 7% 1	1710
	11th to 20th	Day	65% 2 8% 14% 10% 1	1672
	21st to end	Day	66% 2 5% 16% 10% 1	1422
March	1st to 10th	Day	61% 2 10% 17% 9% 1	3394
	11th to 20th	Day	64% 2 9% 16% 8% 1	3480
	21st to end	Day	58% 1 8% 19% 12% 2	3815
April	1st to 10th	Day	59% 2 9% 20% 9% 1	2251
	11th to 20th	Day	56% 2 5% 24% 11% 1	2411
	21st to end	Day	55% 2 7% 19% 15% 3	2470
May	1st to 10th	Day	54% 1 7% 24% 13% 1	4266
	11th to 20th	Day	48% 2 11% 29% 9% 1	4402
	21st to end	Day	47% 2 12% 21% 17% 1	4837
June	1st to 10th	Day	53% 3 10% 23% 11% 1	2849
	11th to 20th	Day	45% 4 12% 25% 14% 1	2850
	21st to end	Day	52% 4 12% 21% 10% 1	2850
July	1st to 10th	Day	48% 6% 14% 25% 7%	4686
	11th to 20th	Day	40% 5% 17% 31% 6%	4679
	21st to end	Day	38% 4 15% 32% 10%	4620
August	1st to 10th	Day	43% 5% 14% 31% 7%	4091
	11th to 20th	Day	46% 4 16% 26% 8% 1	4083
	21st to end	Day	41% 4 12% 33% 9% 1	4450
September	1st to 10th	Day	48% 3 13% 25% 10% 1	2280
	11th to 20th	Day	45% 4 15% 27% 9%	2167
	21st to end	Day	53% 4 12% 24% 7%	2055
October	1st to 10th	Day	49% 4 11% 28% 6%	3160
	11th to 20th	Day	55% 4 11% 21% 8%	3140
	21st to end	Day	67% 4 14% 10% 4	3335
November	1st to 10th	Day	61% 3 13% 17% 6%	1550
	11th to 20th	Day	68% 2 11% 13% 5% 1	1520
	21st to end	Day	76% 2 8% 9% 4	1520
December	1st to 10th	Day	73% 3 8% 11% 4	1520
	11th to 20th	Day	67% 2 9% 17% 5%	1724
	21st to end	Day	78% 1 6% 12% 2	2431
January	1st to 10th	Night	73% 2 11% 10% 4	4748
	11th to 20th	Night	70% 1 10% 14% 4	4712
	21st to end	Night	76% 2 5% 10% 6% 1	4532
February	1st to 10th	Night	65% 3 8% 16% 7% 1	2470
	11th to 20th	Night	66% 2 8% 16% 6% 1	2405
	21st to end	Night	64% 3 7% 16% 9% 1	2027
March	1st to 10th	Night	58% 1 9% 17% 13% 2	3458
	11th to 20th	Night	62% 1 10% 17% 9% 1	3480
	21st to end	Night	54% 2 7% 20% 13% 3	3817
April	1st to 10th	Night	59% 2 8% 17% 12% 2	1929
	11th to 20th	Night	54% 2 5% 22% 15% 2	1735
	21st to end	Night	53% 3 11% 15% 16% 3	1710
May	1st to 10th	Night	53% 1 7% 22% 15% 1	2694
	11th to 20th	Night	46% 2 10% 28% 13% 2	2496
	21st to end	Night	44% 2 12% 23% 15% 4	2724
June	1st to 10th	Night	49% 3 10% 25% 11% 3	1330
	11th to 20th	Night	41% 4 12% 26% 16% 2	1330
	21st to end	Night	47% 5% 13% 21% 14% 1	1330
July	1st to 10th	Night	42% 5% 13% 28% 12% 1	2175
	11th to 20th	Night	41% 6% 16% 29% 8% 1	2168
	21st to end	Night	36% 3 14% 30% 17%	2689
August	1st to 10th	Night	40% 6% 15% 29% 9%	2814
	11th to 20th	Night	42% 6% 17% 29% 7%	2812
	21st to end	Night	38% 5% 16% 29% 12% 1	3174
September	1st to 10th	Night	38% 4 16% 29% 11% 2	1900
	11th to 20th	Night	39% 3 15% 32% 11%	2009
	21st to end	Night	45% 3 15% 28% 9%	2124
October	1st to 10th	Night	47% 5% 12% 26% 10%	3800
	11th to 20th	Night	53% 4 13% 26% 5%	3779
	21st to end	Night	58% 6% 18% 13% 5%	4209
November	1st to 10th	Night	57% 3 15% 20% 6%	2687
	11th to 20th	Night	66% 3 10% 15% 6% 1	2660
	21st to end	Night	71% 3 11% 11% 4	2660
December	1st to 10th	Night	74% 2 8% 13% 3	2660
	11th to 20th	Night	69% 2 8% 15% 6%	3468
	21st to end	Night	78% 1 5% 12% 4	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	28% 16% 34% 17% 4 1	180
	11th to 20th	Day	23% 12% 41% 16% 8%	189
	21st to end	Day	27% 8% 36% 21% 6% 1	297
February	1st to 10th	Day	32% 24% 30% 10% 4	270
	11th to 20th	Day	25% 21% 39% 14% 1	270
	21st to end	Day	35% 22% 35% 8%	225
March	1st to 10th	Day	23% 20% 35% 18% 4	430
	11th to 20th	Day	22% 18% 38% 19% 3 1	460
	21st to end	Day	27% 18% 33% 16% 4 1	506
April	1st to 10th	Day	27% 19% 28% 18% 7% 1	460
	11th to 20th	Day	37% 15% 24% 15% 6% 2	452
	21st to end	Day	33% 16% 31% 12% 5% 2	460
May	1st to 10th	Day	26% 11% 30% 20% 12% 1	463
	11th to 20th	Day	23% 14% 30% 22% 9% 2	487
	21st to end	Day	23% 12% 33% 22% 8% 2	529
June	1st to 10th	Day	21% 15% 35% 22% 6% 2	679
	11th to 20th	Day	17% 16% 33% 24% 8% 2	680
	21st to end	Day	22% 11% 32% 24% 10% 2	680
July	1st to 10th	Day	14% 11% 33% 30% 10% 2	671
	11th to 20th	Day	17% 9% 31% 27% 14% 3	668
	21st to end	Day	15% 7% 30% 31% 12% 4	558
August	1st to 10th	Day	20% 7% 27% 27% 14% 4	486
	11th to 20th	Day	19% 4 26% 26% 16% 9%	479
	21st to end	Day	20% 9% 28% 23% 15% 5%	539
September	1st to 10th	Day	25% 11% 29% 22% 10% 3	490
	11th to 20th	Day	19% 6% 30% 29% 10% 6%	490
	21st to end	Day	29% 9% 24% 22% 12% 3	490
October	1st to 10th	Day	28% 14% 25% 19% 11% 2	490
	11th to 20th	Day	31% 18% 34% 13% 3 1	490
	21st to end	Day	34% 15% 35% 13% 2	482
November	1st to 10th	Day	38% 13% 35% 12% 1 1	197
	11th to 20th	Day	27% 21% 33% 15% 3 2	180
	21st to end	Day	41% 15% 27% 15% 2 1	180
December	1st to 10th	Day	32% 13% 34% 19% 2	180
	11th to 20th	Day	31% 17% 36% 12% 4 1	180
	21st to end	Day	33% 16% 34% 13% 4 1	198
January	1st to 10th	Night	27% 13% 33% 21% 6%	950
	11th to 20th	Night	30% 13% 29% 21% 5%	938
	21st to end	Night	22% 11% 32% 24% 9% 1	836
February	1st to 10th	Night	19% 17% 37% 21% 4 1	760
	11th to 20th	Night	23% 15% 38% 19% 5%	743
	21st to end	Night	24% 18% 34% 20% 4	628
March	1st to 10th	Night	21% 19% 34% 21% 5%	760
	11th to 20th	Night	24% 15% 35% 18% 6% 1	760
	21st to end	Night	20% 14% 35% 24% 6% 1	836
April	1st to 10th	Night	28% 13% 30% 23% 5%	760
	11th to 20th	Night	27% 15% 29% 21% 7% 1	611
	21st to end	Night	28% 11% 28% 23% 9% 1	570
May	1st to 10th	Night	21% 9% 30% 31% 9% 1	489
	11th to 20th	Night	22% 8% 32% 26% 11% 1	374
	21st to end	Night	19% 9% 34% 32% 6%	411
June	1st to 10th	Night	21% 6% 30% 33% 10%	380
	11th to 20th	Night	20% 9% 28% 32% 11% 1	380
	21st to end	Night	21% 8% 25% 30% 15% 1	380
July	1st to 10th	Night	12% 6% 31% 40% 10% 1	370
	11th to 20th	Night	13% 7% 26% 38% 15% 1	368
	21st to end	Night	12% 4 27% 39% 16% 1	459
August	1st to 10th	Night	16% 3 26% 37% 17% 1	567
	11th to 20th	Night	17% 4 23% 32% 21% 3	564
	21st to end	Night	21% 6% 25% 30% 15% 2	651
September	1st to 10th	Night	20% 6% 28% 29% 17% 1	760
	11th to 20th	Night	20% 8% 25% 28% 17% 3	760
	21st to end	Night	24% 5% 26% 29% 14% 2	760
October	1st to 10th	Night	25% 11% 26% 28% 8% 1	760
	11th to 20th	Night	35% 10% 27% 21% 7% 1	760
	21st to end	Night	36% 12% 26% 22% 4 1	836
November	1st to 10th	Night	30% 11% 32% 22% 5% 1	771
	11th to 20th	Night	30% 14% 29% 20% 7%	760
	21st to end	Night	33% 13% 28% 19% 5% 1	760
December	1st to 10th	Night	34% 13% 31% 16% 5% 1	760
	11th to 20th	Night	29% 14% 33% 17% 5% 1	893
	21st to end	Night	31% 14% 29% 20% 5% 1	1045

Page generated at 2024-11-05 08:15:49. Version ac07

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