Gros Morne National Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Gros Morne National Park clear sky chart from 2005-11-06 to 2024-11-28.

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	22% 16% 6% 11% 6% 5% 4 3 4 5% 19%	101917
	Night	19% 18% 7% 15% 7% 5% 4 3 3 4 15%	97764
Transparency	Day	68% 5% 9% 12% 4	105340
	Night	74% 5% 7% 10% 4 1	102449
Seeing	Day	32% 20% 26% 15% 6% 1	18091
	Night	32% 19% 23% 18% 6% 1	25098

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	7% 19% 10% 20% 17% 10% 3 2 2 2 7%	2406
	11th to 20th	Day	10% 20% 11% 29% 12% 8% 3 1 2 2 3	2530
	21st to end	Day	5% 13% 8% 25% 18% 9% 7% 2 2 2 8%	2783
February	1st to 10th	Day	12% 17% 7% 18% 19% 10% 6% 2 3 3 4	1520
	11th to 20th	Day	10% 22% 9% 20% 11% 9% 4 3 2 2 7%	1697
	21st to end	Day	10% 18% 7% 18% 11% 8% 7% 4 3 3 11%	1570
March	1st to 10th	Day	8% 19% 7% 13% 11% 9% 6% 4 3 4 17%	3114
	11th to 20th	Day	10% 31% 11% 17% 7% 5% 4 2 2 2 8%	3244
	21st to end	Day	21% 16% 9% 15% 6% 4 3 3 3 3 17%	4167
April	1st to 10th	Day	17% 21% 9% 16% 9% 3 3 2 4 4 12%	2280
	11th to 20th	Day	15% 15% 7% 11% 5% 4 4 4 5% 6% 23%	2334
	21st to end	Day	21% 17% 5% 10% 5% 4 3 3 4 5% 24%	2521
May	1st to 10th	Day	20% 20% 5% 9% 5% 4 4 3 5% 6% 19%	4425
	11th to 20th	Day	16% 16% 4 8% 5% 4 5% 4 5% 7% 26%	4398
	21st to end	Day	28% 18% 4 8% 4 3 3 3 4 6% 19%	5078
June	1st to 10th	Day	28% 15% 4 8% 5% 4 4 4 4 6% 17%	2850
	11th to 20th	Day	24% 12% 3 6% 5% 4 5% 3 5% 6% 26%	2850
	21st to end	Day	27% 13% 3 7% 4 4 4 3 5% 5% 26%	2850
July	1st to 10th	Day	30% 11% 3 7% 4 4 4 4 5% 5% 22%	4750
	11th to 20th	Day	28% 11% 3 8% 5% 4 5% 3 5% 4 26%	4443
	21st to end	Day	27% 9% 3 6% 4 4 4 3 5% 7% 28%	4815
August	1st to 10th	Day	28% 10% 3 7% 4 4 4 4 6% 7% 24%	4424
	11th to 20th	Day	25% 10% 3 6% 3 3 3 3 5% 6% 33%	4246
	21st to end	Day	30% 8% 2 6% 4 3 3 3 4 6% 30%	4318
September	1st to 10th	Day	29% 10% 3 6% 4 4 4 4 4 7% 26%	2280
	11th to 20th	Day	36% 12% 2 5% 3 3 4 3 4 6% 22%	2180
	21st to end	Day	30% 13% 4 7% 4 4 3 3 5% 6% 21%	2090
October	1st to 10th	Day	26% 19% 3 6% 5% 3 4 3 4 4 23%	1977
	11th to 20th	Day	29% 24% 3 7% 3 3 4 3 3 5% 16%	1762
	21st to end	Day	27% 27% 7% 8% 3 2 2 1 3 3 15%	1881
November	1st to 10th	Day	26% 31% 10% 10% 3 3 3 2 2 3 8%	1760
	11th to 20th	Day	23% 26% 9% 14% 4 2 2 3 3 3 12%	1555
	21st to end	Day	18% 28% 10% 19% 6% 2 2 2 3 3 8%	1379
December	1st to 10th	Day	18% 25% 12% 21% 6% 3 3 2 3 2 5%	1330
	11th to 20th	Day	21% 19% 10% 20% 12% 6% 1 2 2 2 5%	1668
	21st to end	Day	14% 26% 10% 21% 9% 5% 2 2 2 2 7%	2442
January	1st to 10th	Night	7% 20% 11% 21% 15% 13% 4 2 2 2 3	4544
	11th to 20th	Night	11% 18% 8% 31% 10% 7% 4 2 2 2 5%	4440
	21st to end	Night	6% 11% 8% 28% 14% 8% 6% 5% 3 2 9%	4884
February	1st to 10th	Night	12% 18% 8% 21% 17% 11% 5% 1 1 2 5%	2660
	11th to 20th	Night	12% 19% 8% 20% 13% 8% 5% 3 3 3 6%	2367
	21st to end	Night	8% 17% 6% 18% 14% 9% 6% 4 4 3 12%	1884
March	1st to 10th	Night	9% 17% 6% 14% 13% 7% 4 3 4 5% 17%	3726
	11th to 20th	Night	7% 24% 13% 22% 9% 6% 4 2 2 2 8%	3713
	21st to end	Night	18% 17% 9% 15% 7% 5% 4 2 4 5% 14%	3465
April	1st to 10th	Night	19% 21% 9% 16% 6% 3 3 2 3 4 13%	1900
	11th to 20th	Night	14% 20% 7% 12% 5% 4 4 4 5% 4 22%	1795
	21st to end	Night	17% 16% 6% 10% 6% 3 4 3 5% 6% 23%	1657
May	1st to 10th	Night	19% 18% 4 11% 4 4 4 3 6% 6% 20%	2525
	11th to 20th	Night	13% 16% 3 9% 5% 4 5% 4 5% 6% 29%	2506
	21st to end	Night	29% 16% 3 7% 4 4 4 2 5% 5% 21%	2503
June	1st to 10th	Night	24% 13% 3 11% 6% 5% 5% 3 5% 6% 19%	1330
	11th to 20th	Night	22% 11% 5% 7% 5% 4 4 3 6% 6% 28%	1330
	21st to end	Night	28% 11% 3 8% 4 3 4 4 5% 6% 24%	1330
July	1st to 10th	Night	31% 10% 4 8% 4 4 3 3 6% 6% 22%	2220
	11th to 20th	Night	27% 11% 3 7% 5% 4 4 3 5% 6% 25%	2523
	21st to end	Night	24% 9% 4 9% 4 4 3 3 4 6% 31%	2750
August	1st to 10th	Night	26% 12% 4 10% 5% 5% 4 4 5% 6% 19%	2516
	11th to 20th	Night	29% 10% 3 8% 4 4 3 3 5% 4 27%	2590
	21st to end	Night	29% 8% 2 6% 3 4 3 3 5% 6% 30%	3340
September	1st to 10th	Night	31% 9% 2 7% 5% 4 4 3 4 6% 24%	1900
	11th to 20th	Night	34% 12% 4 7% 3 3 3 3 4 5% 21%	2000
	21st to end	Night	35% 13% 2 7% 3 4 4 3 5% 7% 19%	2090
October	1st to 10th	Night	26% 18% 4 7% 4 4 4 3 5% 5% 20%	2199
	11th to 20th	Night	29% 24% 4 6% 4 3 3 2 3 4 17%	2418
	21st to end	Night	30% 25% 5% 7% 3 2 2 2 3 4 15%	2717
November	1st to 10th	Night	25% 32% 10% 10% 4 2 3 2 2 3 8%	2538
	11th to 20th	Night	23% 28% 9% 14% 3 3 2 2 3 3 10%	2842
	21st to end	Night	19% 29% 11% 17% 4 3 3 2 3 3 6%	2956
December	1st to 10th	Night	16% 26% 11% 22% 6% 3 3 1 2 3 6%	2850
	11th to 20th	Night	20% 21% 9% 21% 11% 4 2 2 2 2 5%	3531
	21st to end	Night	15% 22% 11% 25% 11% 5% 2 1 1 2 5%	5225

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% 3 4 6% 1	2407
	11th to 20th	Day	89% 4 3 3 1	2530
	21st to end	Day	85% 2 2 5% 3 3	2783
February	1st to 10th	Day	87% 3 3 4 2	1520
	11th to 20th	Day	86% 2 3 7% 2	1705
	21st to end	Day	79% 4 4 7% 5% 1	1570
March	1st to 10th	Day	70% 6% 6% 9% 9% 2	3118
	11th to 20th	Day	83% 5% 4 5% 3	3244
	21st to end	Day	73% 4 5% 12% 5% 1	4167
April	1st to 10th	Day	77% 5% 6% 8% 4	2280
	11th to 20th	Day	62% 6% 7% 16% 7% 1	2334
	21st to end	Day	64% 6% 7% 14% 8% 1	2521
May	1st to 10th	Day	63% 10% 7% 16% 5%	4440
	11th to 20th	Day	54% 10% 13% 17% 5%	4402
	21st to end	Day	65% 6% 9% 14% 5%	5078
June	1st to 10th	Day	67% 7% 10% 12% 4	2850
	11th to 20th	Day	58% 7% 14% 17% 3	2850
	21st to end	Day	61% 5% 11% 16% 7% 1	2850
July	1st to 10th	Day	63% 5% 11% 17% 4	4675
	11th to 20th	Day	62% 4 15% 16% 4	4366
	21st to end	Day	56% 5% 17% 19% 2	4662
August	1st to 10th	Day	59% 5% 16% 17% 2	4410
	11th to 20th	Day	53% 5% 13% 17% 9% 3	4288
	21st to end	Day	56% 4 16% 20% 5%	4318
September	1st to 10th	Day	58% 8% 11% 18% 6%	2280
	11th to 20th	Day	64% 5% 13% 13% 4 1	2180
	21st to end	Day	63% 6% 12% 13% 5%	2090
October	1st to 10th	Day	61% 5% 9% 18% 7% 1	3289
	11th to 20th	Day	78% 4 9% 7% 2	2908
	21st to end	Day	78% 4 7% 8% 3	3092
November	1st to 10th	Day	85% 3 6% 6% 1	1760
	11th to 20th	Day	79% 4 6% 8% 3	1555
	21st to end	Day	84% 4 5% 5% 1	1379
December	1st to 10th	Day	88% 3 5% 3 1	1330
	11th to 20th	Day	88% 4 4 3 1	1667
	21st to end	Day	85% 4 4 5% 1	2442
January	1st to 10th	Night	90% 4 3 2 1	4544
	11th to 20th	Night	86% 4 3 5% 2	4440
	21st to end	Night	83% 3 2 4 3 4	4884
February	1st to 10th	Night	89% 3 2 3 2 1	2660
	11th to 20th	Night	86% 5% 4 4 1	2370
	21st to end	Night	79% 5% 4 7% 5%	1884
March	1st to 10th	Night	70% 6% 5% 10% 8% 1	3735
	11th to 20th	Night	85% 4 2 6% 2	3714
	21st to end	Night	73% 5% 8% 10% 4 1	3465
April	1st to 10th	Night	76% 5% 6% 9% 3	1900
	11th to 20th	Night	65% 6% 6% 14% 8%	1795
	21st to end	Night	63% 6% 10% 12% 8% 1	1657
May	1st to 10th	Night	63% 7% 8% 16% 5% 1	2530
	11th to 20th	Night	52% 8% 11% 20% 8% 1	2507
	21st to end	Night	65% 6% 10% 15% 5%	2504
June	1st to 10th	Night	66% 7% 9% 13% 4 1	1330
	11th to 20th	Night	56% 6% 13% 19% 5%	1330
	21st to end	Night	60% 6% 12% 15% 6%	1330
July	1st to 10th	Night	63% 4 10% 16% 6%	2186
	11th to 20th	Night	61% 5% 12% 16% 6% 1	2476
	21st to end	Night	53% 5% 17% 22% 2	2663
August	1st to 10th	Night	65% 6% 14% 14% 1	2505
	11th to 20th	Night	61% 5% 12% 12% 7% 4	2614
	21st to end	Night	56% 3 16% 20% 4	3339
September	1st to 10th	Night	63% 6% 10% 17% 4	1900
	11th to 20th	Night	66% 5% 11% 13% 4 1	2000
	21st to end	Night	65% 6% 11% 13% 4	2090
October	1st to 10th	Night	60% 5% 10% 16% 9%	3667
	11th to 20th	Night	79% 3 7% 9% 2	4019
	21st to end	Night	76% 3 9% 8% 2 1	4467
November	1st to 10th	Night	84% 5% 4 5% 1	2538
	11th to 20th	Night	82% 3 6% 6% 2	2842
	21st to end	Night	85% 4 4 5% 1	2956
December	1st to 10th	Night	88% 3 5% 5% 1	2850
	11th to 20th	Night	88% 5% 3 3 2	3533
	21st to end	Night	88% 5% 2 4 1	5225

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	24% 33% 26% 11% 6% 1	370
	11th to 20th	Day	26% 28% 27% 13% 4 2	370
	21st to end	Day	26% 31% 27% 13% 3	407
February	1st to 10th	Day	27% 33% 23% 11% 6%	370
	11th to 20th	Day	28% 36% 25% 8% 3 1	366
	21st to end	Day	24% 31% 27% 12% 5% 1	307
March	1st to 10th	Day	21% 33% 29% 11% 4 2	370
	11th to 20th	Day	29% 27% 21% 15% 7% 2	377
	21st to end	Day	31% 24% 27% 12% 4 2	506
April	1st to 10th	Day	29% 30% 29% 10% 2	460
	11th to 20th	Day	24% 21% 32% 16% 7% 1	532
	21st to end	Day	30% 20% 25% 19% 5% 1	650
May	1st to 10th	Day	31% 18% 24% 20% 6% 1	653
	11th to 20th	Day	23% 18% 26% 22% 9% 2	674
	21st to end	Day	33% 16% 27% 16% 6% 1	735
June	1st to 10th	Day	34% 15% 24% 17% 7% 1	680
	11th to 20th	Day	32% 13% 27% 19% 7% 2	680
	21st to end	Day	34% 14% 23% 18% 8% 3	680
July	1st to 10th	Day	35% 11% 26% 17% 9% 2	670
	11th to 20th	Day	29% 13% 28% 20% 9% 1	668
	21st to end	Day	32% 13% 25% 21% 7% 1	740
August	1st to 10th	Day	31% 11% 27% 20% 9% 2	675
	11th to 20th	Day	28% 13% 28% 20% 9% 2	667
	21st to end	Day	31% 14% 30% 16% 7% 2	625
September	1st to 10th	Day	35% 18% 26% 16% 5% 1	490
	11th to 20th	Day	41% 18% 25% 13% 3	437
	21st to end	Day	39% 19% 27% 11% 2 1	390
October	1st to 10th	Day	35% 25% 25% 10% 5% 2	390
	11th to 20th	Day	46% 15% 19% 13% 5% 1	390
	21st to end	Day	44% 18% 21% 10% 6% 1	429
November	1st to 10th	Day	44% 27% 20% 7% 3	395
	11th to 20th	Day	39% 23% 22% 11% 4 2	400
	21st to end	Day	37% 27% 26% 8% 2	391
December	1st to 10th	Day	31% 24% 26% 12% 5% 1	370
	11th to 20th	Day	30% 34% 22% 9% 4 1	370
	21st to end	Day	27% 31% 25% 11% 5% 2	407
January	1st to 10th	Night	26% 32% 22% 14% 5% 1	850
	11th to 20th	Night	26% 30% 27% 13% 4 1	850
	21st to end	Night	22% 28% 32% 13% 4 1	935
February	1st to 10th	Night	23% 33% 24% 15% 4	850
	11th to 20th	Night	24% 29% 30% 14% 3 1	752
	21st to end	Night	21% 23% 31% 16% 8% 2	628
March	1st to 10th	Night	22% 28% 29% 16% 3 1	760
	11th to 20th	Night	24% 21% 26% 21% 7%	727
	21st to end	Night	27% 21% 29% 16% 6% 1	627
April	1st to 10th	Night	33% 19% 24% 19% 4 1	570
	11th to 20th	Night	24% 17% 29% 22% 7% 1	564
	21st to end	Night	28% 14% 28% 22% 6% 2	570
May	1st to 10th	Night	31% 11% 20% 25% 10% 2	570
	11th to 20th	Night	30% 14% 20% 25% 11% 1	562
	21st to end	Night	35% 9% 22% 26% 7% 1	616
June	1st to 10th	Night	31% 12% 19% 28% 9% 1	570
	11th to 20th	Night	25% 12% 24% 27% 10% 1	570
	21st to end	Night	31% 9% 25% 25% 9% 1	570
July	1st to 10th	Night	35% 7% 23% 21% 13% 1	556
	11th to 20th	Night	35% 8% 19% 25% 12% 1	552
	21st to end	Night	30% 8% 22% 29% 10%	623
August	1st to 10th	Night	30% 8% 18% 30% 13% 1	568
	11th to 20th	Night	33% 8% 22% 24% 12% 1	562
	21st to end	Night	33% 8% 20% 22% 15% 1	627
September	1st to 10th	Night	37% 13% 22% 22% 6%	570
	11th to 20th	Night	43% 9% 22% 21% 4	570
	21st to end	Night	42% 15% 22% 14% 5% 1	570
October	1st to 10th	Night	39% 16% 25% 15% 4 1	679
	11th to 20th	Night	46% 14% 16% 16% 8% 1	833
	21st to end	Night	46% 16% 16% 16% 5%	946
November	1st to 10th	Night	44% 24% 17% 12% 3	880
	11th to 20th	Night	39% 25% 18% 11% 6% 1	900
	21st to end	Night	37% 27% 22% 11% 2	886
December	1st to 10th	Night	31% 24% 24% 16% 4	850
	11th to 20th	Night	33% 29% 23% 12% 3	850
	21st to end	Night	26% 28% 25% 14% 6% 1	935

Page generated at 2024-11-25 01:22:16. Version ac07

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