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 2024-01-14.

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	23% 16% 6% 10% 8% 4 4 4 4 5% 18%	74554
	Night	21% 18% 8% 12% 9% 4 4 3 3 4 14%	75210
Transparency	Day	70% 5% 9% 12% 4	74251
	Night	75% 5% 7% 9% 3	75048
Seeing	Day	31% 20% 26% 16% 6% 1	16825
	Night	32% 19% 23% 18% 7% 1	23950

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	12% 18% 11% 20% 17% 5% 4 3 3 1 5%	1444
	11th to 20th	Day	13% 19% 11% 19% 15% 8% 6% 2 2 1 4	1465
	21st to end	Day	10% 18% 10% 19% 21% 8% 6% 2 1 1 4	1584
February	1st to 10th	Day	12% 15% 9% 16% 21% 9% 7% 2 2 3 4	1440
	11th to 20th	Day	11% 19% 10% 18% 13% 8% 5% 5% 2 2 7%	1605
	21st to end	Day	9% 17% 8% 16% 13% 6% 8% 6% 3 3 11%	1480
March	1st to 10th	Day	11% 15% 9% 14% 12% 6% 6% 5% 3 4 14%	1796
	11th to 20th	Day	13% 21% 10% 16% 10% 4 5% 3 3 3 13%	1842
	21st to end	Day	14% 20% 10% 13% 11% 5% 3 3 3 3 17%	2376
April	1st to 10th	Day	18% 19% 10% 14% 10% 2 3 3 4 4 12%	2160
	11th to 20th	Day	16% 15% 7% 9% 6% 3 4 5% 4 7% 23%	2209
	21st to end	Day	21% 16% 6% 9% 5% 3 4 3 4 6% 23%	2388
May	1st to 10th	Day	23% 19% 5% 8% 5% 3 3 4 4 6% 21%	2520
	11th to 20th	Day	22% 16% 4 6% 5% 2 4 4 4 5% 28%	2478
	21st to end	Day	26% 17% 4 7% 4 3 4 4 5% 5% 21%	2862
June	1st to 10th	Day	28% 14% 5% 7% 6% 3 5% 5% 4 6% 18%	2700
	11th to 20th	Day	24% 10% 4 6% 6% 3 4 4 5% 6% 27%	2700
	21st to end	Day	28% 11% 3 6% 5% 3 4 4 4 6% 25%	2700
July	1st to 10th	Day	30% 9% 3 6% 5% 3 5% 6% 6% 5% 23%	2700
	11th to 20th	Day	26% 9% 3 6% 5% 3 4 4 6% 6% 29%	2523
	21st to end	Day	29% 9% 4 6% 6% 3 5% 4 5% 6% 23%	2745
August	1st to 10th	Day	24% 10% 4 7% 5% 3 4 5% 5% 7% 27%	2506
	11th to 20th	Day	29% 10% 3 5% 5% 3 3 4 5% 7% 27%	2424
	21st to end	Day	32% 7% 3 5% 5% 3 3 4 5% 7% 26%	2458
September	1st to 10th	Day	29% 9% 3 5% 5% 3 4 4 4 7% 26%	2160
	11th to 20th	Day	36% 12% 3 4 4 2 4 4 4 6% 21%	2066
	21st to end	Day	31% 12% 3 6% 5% 3 3 4 5% 7% 21%	1980
October	1st to 10th	Day	26% 18% 3 5% 5% 2 4 4 4 4 23%	1873
	11th to 20th	Day	29% 22% 4 6% 4 2 4 4 4 5% 16%	1670
	21st to end	Day	28% 26% 7% 6% 4 1 2 2 3 4 16%	1782
November	1st to 10th	Day	27% 30% 10% 8% 4 2 3 2 2 3 8%	1670
	11th to 20th	Day	23% 26% 9% 12% 5% 1 2 3 3 4 12%	1478
	21st to end	Day	19% 27% 11% 17% 7% 2 2 2 3 3 8%	1330
December	1st to 10th	Day	18% 23% 13% 18% 9% 2 3 3 3 2 5%	1330
	11th to 20th	Day	21% 17% 11% 16% 16% 5% 2 2 2 2 5%	1668
	21st to end	Day	14% 24% 11% 16% 14% 4 3 2 2 2 7%	2442
January	1st to 10th	Night	12% 21% 12% 18% 15% 8% 4 2 3 2 4	2716
	11th to 20th	Night	13% 20% 11% 19% 13% 8% 6% 2 2 2 4	2573
	21st to end	Night	11% 16% 10% 20% 20% 7% 6% 2 2 2 4	2772
February	1st to 10th	Night	12% 15% 9% 17% 21% 10% 6% 2 1 1 4	2520
	11th to 20th	Night	12% 16% 10% 17% 16% 7% 6% 4 3 3 6%	2239
	21st to end	Night	8% 16% 7% 16% 16% 7% 6% 5% 3 4 12%	1776
March	1st to 10th	Night	11% 14% 9% 14% 15% 7% 5% 4 4 5% 12%	2151
	11th to 20th	Night	11% 20% 9% 15% 10% 5% 5% 4 4 4 13%	2115
	21st to end	Night	15% 20% 8% 12% 9% 5% 4 3 4 5% 16%	1980
April	1st to 10th	Night	21% 20% 9% 14% 8% 2 3 3 3 4 13%	1800
	11th to 20th	Night	14% 20% 7% 11% 5% 3 3 5% 5% 4 22%	1700
	21st to end	Night	17% 16% 6% 9% 7% 2 4 4 5% 6% 23%	1570
May	1st to 10th	Night	25% 15% 4 8% 4 3 3 4 5% 5% 25%	1440
	11th to 20th	Night	19% 18% 4 8% 5% 3 4 4 4 5% 28%	1416
	21st to end	Night	28% 12% 4 6% 6% 3 5% 4 5% 5% 23%	1408
June	1st to 10th	Night	24% 12% 4 10% 8% 3 6% 4 5% 5% 19%	1260
	11th to 20th	Night	22% 11% 4 6% 5% 3 4 4 5% 6% 29%	1260
	21st to end	Night	29% 10% 3 7% 5% 2 4 4 5% 7% 24%	1260
July	1st to 10th	Night	31% 9% 3 6% 5% 2 4 5% 6% 6% 24%	1260
	11th to 20th	Night	30% 9% 3 5% 5% 3 3 4 4 5% 28%	1433
	21st to end	Night	30% 9% 4 7% 6% 4 5% 4 4 5% 22%	1573
August	1st to 10th	Night	27% 9% 5% 8% 5% 4 4 5% 6% 6% 22%	1433
	11th to 20th	Night	30% 8% 3 5% 6% 3 4 4 5% 5% 27%	1475
	21st to end	Night	32% 8% 2 5% 4 3 4 4 5% 6% 28%	1896
September	1st to 10th	Night	32% 9% 2 6% 6% 3 4 4 4 6% 24%	1800
	11th to 20th	Night	35% 11% 4 6% 4 3 3 3 4 5% 22%	1894
	21st to end	Night	36% 12% 2 6% 4 3 4 3 4 7% 19%	1980
October	1st to 10th	Night	27% 18% 4 6% 5% 3 4 4 5% 5% 20%	2083
	11th to 20th	Night	30% 23% 4 6% 5% 2 3 3 3 4 17%	2290
	21st to end	Night	31% 25% 4 6% 4 2 2 3 3 4 16%	2574
November	1st to 10th	Night	26% 31% 9% 9% 4 2 3 2 3 3 8%	2408
	11th to 20th	Night	24% 26% 11% 13% 4 2 3 2 3 3 10%	2699
	21st to end	Night	19% 27% 12% 16% 6% 2 3 2 3 3 6%	2850
December	1st to 10th	Night	17% 24% 13% 20% 8% 2 3 2 2 3 6%	2850
	11th to 20th	Night	21% 19% 11% 19% 14% 4 1 2 2 2 5%	3531
	21st to end	Night	15% 20% 11% 20% 16% 4 3 2 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	89% 3 3 4 1	1445
	11th to 20th	Day	91% 3 3 3 1	1465
	21st to end	Day	91% 2 2 3 1	1584
February	1st to 10th	Day	88% 3 3 4 2	1440
	11th to 20th	Day	85% 3 3 7% 2	1613
	21st to end	Day	79% 4 4 7% 5% 1	1480
March	1st to 10th	Day	74% 5% 7% 10% 4	1800
	11th to 20th	Day	77% 6% 5% 8% 5%	1842
	21st to end	Day	75% 4 5% 8% 7% 1	2376
April	1st to 10th	Day	78% 4 6% 7% 4	2160
	11th to 20th	Day	63% 6% 7% 16% 7% 1	2209
	21st to end	Day	64% 6% 7% 14% 8% 1	2388
May	1st to 10th	Day	65% 6% 7% 14% 7%	2520
	11th to 20th	Day	59% 7% 8% 18% 7% 1	2482
	21st to end	Day	65% 5% 11% 13% 5%	2862
June	1st to 10th	Day	67% 7% 10% 12% 4	2700
	11th to 20th	Day	58% 8% 13% 18% 3	2700
	21st to end	Day	61% 6% 11% 15% 7% 1	2700
July	1st to 10th	Day	59% 8% 13% 17% 3	2625
	11th to 20th	Day	55% 5% 14% 21% 5%	2446
	21st to end	Day	63% 7% 13% 15% 3	2592
August	1st to 10th	Day	55% 7% 18% 15% 3	2492
	11th to 20th	Day	58% 7% 15% 17% 4	2424
	21st to end	Day	58% 6% 15% 17% 4	2458
September	1st to 10th	Day	57% 8% 11% 17% 6%	2160
	11th to 20th	Day	65% 5% 12% 13% 4 1	2066
	21st to end	Day	63% 6% 12% 13% 5%	1980
October	1st to 10th	Day	64% 5% 9% 16% 5% 1	1873
	11th to 20th	Day	70% 6% 10% 11% 3	1670
	21st to end	Day	75% 4 8% 8% 5% 1	1782
November	1st to 10th	Day	84% 4 6% 6% 1	1670
	11th to 20th	Day	78% 5% 6% 8% 3	1478
	21st to end	Day	85% 4 5% 5% 1	1330
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% 3 3 3 1	2716
	11th to 20th	Night	89% 4 2 4 1	2573
	21st to end	Night	90% 2 2 3 2	2772
February	1st to 10th	Night	90% 3 2 3 1 1	2520
	11th to 20th	Night	85% 5% 4 4 1	2242
	21st to end	Night	79% 5% 4 6% 6%	1776
March	1st to 10th	Night	76% 6% 6% 9% 3	2160
	11th to 20th	Night	76% 5% 4 10% 4 1	2116
	21st to end	Night	73% 4 6% 9% 6% 1	1980
April	1st to 10th	Night	77% 5% 6% 9% 4	1800
	11th to 20th	Night	66% 6% 6% 14% 8%	1700
	21st to end	Night	63% 6% 10% 12% 8%	1570
May	1st to 10th	Night	63% 6% 8% 15% 7% 2	1440
	11th to 20th	Night	59% 6% 9% 18% 8%	1417
	21st to end	Night	62% 6% 10% 16% 5%	1409
June	1st to 10th	Night	67% 7% 8% 13% 4 1	1260
	11th to 20th	Night	55% 7% 13% 20% 5%	1260
	21st to end	Night	61% 6% 13% 15% 5%	1260
July	1st to 10th	Night	59% 7% 14% 16% 4	1226
	11th to 20th	Night	58% 6% 11% 19% 5% 1	1386
	21st to end	Night	62% 6% 14% 16% 2	1486
August	1st to 10th	Night	59% 9% 14% 15% 2	1422
	11th to 20th	Night	60% 7% 12% 16% 5%	1475
	21st to end	Night	58% 6% 15% 17% 5%	1896
September	1st to 10th	Night	63% 6% 10% 17% 3 1	1800
	11th to 20th	Night	66% 5% 11% 13% 4 1	1894
	21st to end	Night	66% 7% 11% 13% 4	1980
October	1st to 10th	Night	65% 6% 10% 12% 5% 1	2083
	11th to 20th	Night	73% 5% 8% 11% 3	2290
	21st to end	Night	73% 4 8% 10% 4 1	2574
November	1st to 10th	Night	83% 5% 4 5% 1	2408
	11th to 20th	Night	82% 4 6% 7% 2	2699
	21st to end	Night	85% 4 4 5% 2	2850
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	24% 29% 27% 13% 4 2	350
	21st to end	Day	26% 32% 27% 13% 3	374
February	1st to 10th	Day	27% 35% 22% 11% 4	340
	11th to 20th	Day	26% 35% 26% 9% 3 1	336
	21st to end	Day	22% 32% 29% 11% 5% 1	280
March	1st to 10th	Day	20% 33% 31% 10% 4 2	340
	11th to 20th	Day	28% 27% 22% 15% 6% 2	346
	21st to end	Day	28% 25% 29% 13% 4 2	462
April	1st to 10th	Day	32% 30% 26% 9% 2	420
	11th to 20th	Day	25% 20% 31% 17% 7% 1	487
	21st to end	Day	30% 20% 25% 19% 5% 2	600
May	1st to 10th	Day	32% 18% 24% 19% 6% 1	603
	11th to 20th	Day	24% 17% 26% 20% 9% 2	624
	21st to end	Day	34% 15% 26% 17% 7% 1	680
June	1st to 10th	Day	35% 14% 24% 18% 7% 2	630
	11th to 20th	Day	30% 13% 28% 20% 7% 2	630
	21st to end	Day	34% 13% 23% 18% 9% 3	630
July	1st to 10th	Day	34% 11% 25% 18% 9% 2	620
	11th to 20th	Day	28% 13% 28% 21% 9% 1	618
	21st to end	Day	32% 12% 25% 23% 8% 2	685
August	1st to 10th	Day	29% 11% 27% 22% 10% 2	625
	11th to 20th	Day	28% 12% 27% 21% 9% 2	617
	21st to end	Day	30% 14% 29% 17% 8% 2	577
September	1st to 10th	Day	34% 18% 26% 17% 5% 1	450
	11th to 20th	Day	41% 17% 25% 14% 3	403
	21st to end	Day	40% 20% 26% 11% 2 1	360
October	1st to 10th	Day	34% 26% 24% 9% 5% 2	360
	11th to 20th	Day	44% 15% 20% 14% 6% 1	360
	21st to end	Day	42% 18% 21% 11% 7% 1	396
November	1st to 10th	Day	42% 27% 21% 7% 3	365
	11th to 20th	Day	38% 23% 22% 12% 5% 2	370
	21st to end	Day	36% 26% 27% 9% 2	370
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	819
	21st to end	Night	23% 28% 32% 14% 3 1	880
February	1st to 10th	Night	23% 34% 25% 15% 3	800
	11th to 20th	Night	24% 28% 29% 14% 4 1	711
	21st to end	Night	20% 22% 31% 16% 8% 2	592
March	1st to 10th	Night	21% 29% 29% 17% 4 1	720
	11th to 20th	Night	24% 21% 27% 22% 6%	689
	21st to end	Night	26% 21% 29% 16% 6% 1	594
April	1st to 10th	Night	35% 19% 22% 19% 5% 1	540
	11th to 20th	Night	24% 17% 28% 22% 7% 1	534
	21st to end	Night	27% 14% 28% 22% 6% 2	540
May	1st to 10th	Night	32% 11% 21% 24% 10% 3	540
	11th to 20th	Night	30% 13% 20% 24% 11% 1	532
	21st to end	Night	34% 9% 22% 26% 7% 1	583
June	1st to 10th	Night	32% 11% 18% 29% 10% 1	540
	11th to 20th	Night	25% 12% 24% 28% 11% 1	540
	21st to end	Night	31% 8% 25% 25% 10% 1	540
July	1st to 10th	Night	35% 7% 23% 21% 13% 1	526
	11th to 20th	Night	34% 8% 18% 26% 13% 1	522
	21st to end	Night	30% 8% 21% 30% 11%	590
August	1st to 10th	Night	29% 7% 18% 31% 14% 1	538
	11th to 20th	Night	32% 8% 21% 24% 13% 2	532
	21st to end	Night	33% 8% 20% 23% 15% 2	594
September	1st to 10th	Night	37% 13% 21% 22% 7%	540
	11th to 20th	Night	42% 10% 22% 21% 4	540
	21st to end	Night	44% 16% 22% 14% 4 1	540
October	1st to 10th	Night	40% 16% 25% 14% 4 1	643
	11th to 20th	Night	45% 14% 16% 16% 8% 1	785
	21st to end	Night	45% 16% 16% 16% 6%	891
November	1st to 10th	Night	44% 24% 17% 12% 3	830
	11th to 20th	Night	38% 25% 19% 12% 6% 1	850
	21st to end	Night	36% 28% 22% 11% 2	850
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 2024-01-11 14:32:00. Version ac07

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